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Wednesday 17 September 2014

Java Awt Quick Guide 9

AWT FlowLayout Class

Introduction

The class FlowLayout components in a left-to-right flow.

Class declaration

Following is the declaration for java.awt.FlowLayout class:
public class FlowLayout
   extends Object
      implements LayoutManager, Serializable

Field

Following are the fields for java.awt.BorderLayout class:
  • static int CENTER -- This value indicates that each row of components should be centered.
  • static int LEADING -- This value indicates that each row of components should be justified to the leading edge of the container's orientation, for example, to the left in left-to-right orientations.
  • static int LEFT -- This value indicates that each row of components should be left-justified.
  • static int RIGHT -- This value indicates that each row of components should be right-justified.
  • static int TRAILING -- This value indicates that each row of components should be justified to the trailing edge of the container's orientation, for example, to the right in left-to-right orientations.

Class constructors

S.N.Constructor & Description
1FlowLayout()
Constructs a new FlowLayout with a centered alignment and a default 5-unit horizontal and vertical gap.
2FlowLayout(int align)
Constructs a new FlowLayout with the specified alignment and a default 5-unit horizontal and vertical gap.
3FlowLayout(int align, int hgap, int vgap)
Creates a new flow layout manager with the indicated alignment and the indicated horizontal and vertical gaps.

Class methods

S.N.Method & Description
1void addLayoutComponent(String name, Component comp)
Adds the specified component to the layout.
2int getAlignment()
Gets the alignment for this layout.
3int getHgap()
Gets the horizontal gap between components.
4int getVgap()
Gets the vertical gap between components.
5void layoutContainer(Container target)
Lays out the container.
6Dimension minimumLayoutSize(Container target)
Returns the minimum dimensions needed to layout the visible components contained in the specified target container.
7Dimension preferredLayoutSize(Container target)
Returns the preferred dimensions for this layout given the visible components in the specified target container.
8void removeLayoutComponent(Component comp)
Removes the specified component from the layout.
9void setAlignment(int align)
Sets the alignment for this layout.
10void setHgap(int hgap)
Sets the horizontal gap between components.
11void setVgap(int vgap)
Sets the vertical gap between components.
12String toString()
Returns a string representation of this FlowLayout object and its values.

Methods inherited

This class inherits methods from the following classes:
  • java.lang.Object

FlowLayout Example

Create the following java program using any editor of your choice in say D:/ > AWT > com > tutorialspoint > gui >
AwtLayoutDemo.java 
package com.tutorialspoint.gui;

import java.awt.*;
import java.awt.event.*;

public class AwtLayoutDemo {
   private Frame mainFrame;
   private Label headerLabel;
   private Label statusLabel;
   private Panel controlPanel;
   private Label msglabel;

   public AwtLayoutDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      AwtLayoutDemo  awtLayoutDemo = new AwtLayoutDemo();  
      awtLayoutDemo.showFlowLayoutDemo();       
   }
      
   private void prepareGUI(){
      mainFrame = new Frame("Java AWT Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new Label();
      headerLabel.setAlignment(Label.CENTER);
      statusLabel = new Label();        
      statusLabel.setAlignment(Label.CENTER);
      statusLabel.setSize(350,100);

      msglabel = new Label();
      msglabel.setAlignment(Label.CENTER);
      msglabel.setText("Welcome to TutorialsPoint AWT Tutorial.");

      controlPanel = new Panel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }

   private void showFlowLayoutDemo(){
      headerLabel.setText("Layout in action: FlowLayout");      

      Panel panel = new Panel();
      panel.setBackground(Color.darkGray);
      panel.setSize(200,200);
      FlowLayout layout = new FlowLayout();
      layout.setHgap(10);              
      layout.setVgap(10);
      panel.setLayout(layout);        
      panel.add(new Button("OK"));
      panel.add(new Button("Cancel"));       

      controlPanel.add(panel);

      mainFrame.setVisible(true);  
   }
}
Compile the program using command prompt. Go to D:/ > AWT and type the following command.
D:\AWT>javac com\tutorialspoint\gui\AwtlayoutDemo.java
If no error comes that means compilation is successful. Run the program using following command.
D:\AWT>java com.tutorialspoint.gui.AwtlayoutDemo
Verify the following output
AWT FlowLayout

AWT GridLayout Class

Introduction

The class GridLayout arranges components in a rectangular grid.

Class declaration

Following is the declaration for java.awt.GridLayout class:
public class GridLayout
   extends Object
      implements LayoutManager, Serializable

Class constructors

S.N.Constructor & Description
1GridLayout()
Creates a grid layout with a default of one column per component, in a single row.
2GridLayout(int rows, int cols)
Creates a grid layout with the specified number of rows and columns.
3GridLayout(int rows, int cols, int hgap, int vgap)
Creates a grid layout with the specified number of rows and columns.

Class methods

S.N.Method & Description
1void addLayoutComponent(String name, Component comp)
Adds the specified component with the specified name to the layout.
2int getColumns()
Gets the number of columns in this layout.
3int getHgap()
Gets the horizontal gap between components.
4int getRows()
Gets the number of rows in this layout.
5int getVgap()
Gets the vertical gap between components.
6void layoutContainer(Container parent)
Lays out the specified container using this layout.
7Dimension minimumLayoutSize(Container parent)
Determines the minimum size of the container argument using this grid layout.
8Dimension preferredLayoutSize(Container parent)
Determines the preferred size of the container argument using this grid layout.
9void removeLayoutComponent(Component comp)
Removes the specified component from the layout.
10void setColumns(int cols)
Sets the number of columns in this layout to the specified value.
11void setHgap(int hgap)
Sets the horizontal gap between components to the specified value.
12void setRows(int rows)
Sets the number of rows in this layout to the specified value.
13void setVgap(int vgap)
Sets the vertical gap between components to the specified value.
14String toString()
Returns the string representation of this grid layout's values.

Methods inherited

This class inherits methods from the following classes:
  • java.lang.Object

GridLayout Example

Create the following java program using any editor of your choice in say D:/ > AWT > com > tutorialspoint > gui >
AwtLayoutDemo.java 
package com.tutorialspoint.gui;

import java.awt.*;
import java.awt.event.*;

public class AwtLayoutDemo {
   private Frame mainFrame;
   private Label headerLabel;
   private Label statusLabel;
   private Panel controlPanel;
   private Label msglabel;

   public AwtLayoutDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      AwtLayoutDemo  awtLayoutDemo = new AwtLayoutDemo();  
      awtLayoutDemo.showGridLayoutDemo();       
   }
      
   private void prepareGUI(){
      mainFrame = new Frame("Java AWT Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new Label();
      headerLabel.setAlignment(Label.CENTER);
      statusLabel = new Label();        
      statusLabel.setAlignment(Label.CENTER);
      statusLabel.setSize(350,100);

      msglabel = new Label();
      msglabel.setAlignment(Label.CENTER);
      msglabel.setText("Welcome to TutorialsPoint AWT Tutorial.");

      controlPanel = new Panel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }

   private void showGridLayoutDemo(){
      headerLabel.setText("Layout in action: GridLayout");      

      Panel panel = new Panel();
      panel.setBackground(Color.darkGray);
      panel.setSize(300,300);
      GridLayout layout = new GridLayout(0,3);
      layout.setHgap(10);
      layout.setVgap(10);
      
      panel.setLayout(layout);        
      panel.add(new Button("Button 1"));
      panel.add(new Button("Button 2")); 
      panel.add(new Button("Button 3")); 
      panel.add(new Button("Button 4")); 
      panel.add(new Button("Button 5")); 
      controlPanel.add(panel);
      mainFrame.setVisible(true);  
   }
}
Compile the program using command prompt. Go to D:/ > AWT and type the following command.
D:\AWT>javac com\tutorialspoint\gui\AwtlayoutDemo.java
If no error comes that means compilation is successful. Run the program using following command.
D:\AWT>java com.tutorialspoint.gui.AwtlayoutDemo
Verify the following output
AWT GridLayout

AWT GridBagLayout Class

Introduction

The class GridBagLayout arranges components in a horizontal and vertical manner.

Class declaration

Following is the declaration for java.awt.GridBagLayout class:
public class GridBagLayout
   extends Object
      implements LayoutManager2, Serializable

Field

Following are the fields for java.awt.BorderLayout class:
  • double[] columnWeights -- This field holds the overrides to the column weights.
  • int[] columnWidths -- This field holds the overrides to the column minimum width.
  • protected Hashtable comptable -- This hashtable maintains the association between a component and its gridbag constraints.
  • protected GridBagConstraints defaultConstraints -- This field holds a gridbag constraints instance containing the default values, so if a component does not have gridbag constraints associated with it, then the component will be assigned a copy of the defaultConstraints.
  • protected java.awt.GridBagLayoutInfo layoutInfo -- This field holds the layout information for the gridbag.
  • protected static int MAXGRIDSIZE -- The maximum number of grid positions (both horizontally and vertically) that can be laid out by the grid bag layout.
  • protected static int MINSIZE -- The smallest grid that can be laid out by the grid bag layout.
  • protected static int PREFERREDSIZE -- The preferred grid size that can be laid out by the grid bag layout.
  • int[] rowHeights -- This field holds the overrides to the row minimum heights.
  • double[] rowWeights -- This field holds the overrides to the row weights.

Class constructors

S.N.Constructor & Description
1GridBagLayout()
Creates a grid bag layout manager.

Class methods

S.N.Method & Description
1void addLayoutComponent(Component comp, Object constraints)
Adds the specified component to the layout, using the specified constraints object.
2void addLayoutComponent(String name, Component comp)
Adds the specified component with the specified name to the layout.
3protected void adjustForGravity(GridBagConstraints constraints, Rectangle r)
Adjusts the x, y, width, and height fields to the correct values depending on the constraint geometry and pads.
4protected void AdjustForGravity(GridBagConstraints constraints, Rectangle r)
This method is obsolete and supplied for backwards compatability only; new code should call adjustForGravity instead.
5protected void arrangeGrid(Container parent)
Lays out the grid.
6protected void ArrangeGrid(Container parent)
This method is obsolete and supplied for backwards compatability only; new code should call arrangeGrid instead.
7GridBagConstraints getConstraints(Component comp)
Gets the constraints for the specified component.
8float getLayoutAlignmentX(Container parent)
Returns the alignment along the x axis.
9float getLayoutAlignmentY(Container parent)
Returns the alignment along the y axis.
10int[][] getLayoutDimensions()
Determines column widths and row heights for the layout grid.
11protected java.awt.GridBagLayoutInfo getLayoutInfo(Container parent, int sizeflag)
Fills in an instance of GridBagLayoutInfo for the current set of managed children.
12protected java.awt.GridBagLayoutInfo GetLayoutInfo(Container parent, int sizeflag)
This method is obsolete and supplied for backwards compatability only; new code should call getLayoutInfo instead.
13Point getLayoutOrigin()
Determines the origin of the layout area, in the graphics coordinate space of the target container.
14double[][] getLayoutWeights()
Determines the weights of the layout grid's columns and rows.
15protected Dimension getMinSize(Container parent, java.awt.GridBagLayoutInfo info)
Figures out the minimum size of the master based on the information from getLayoutInfo().
16protected Dimension GetMinSize(Container parent, java.awt.GridBagLayoutInfo info)
This method is obsolete and supplied for backwards compatability only; new code should call getMinSize instead.
17void invalidateLayout(Container target)
Invalidates the layout, indicating that if the layout manager has cached information it should be discarded.
18void layoutContainer(Container parent)
Lays out the specified container using this grid bag layout.
19Point location(int x, int y)
Determines which cell in the layout grid contains the point specified by (x, y).
20protected GridBagConstraints lookupConstraints(Component comp)
Retrieves the constraints for the specified component.
21Dimension maximumLayoutSize(Container target)
Returns the maximum dimensions for this layout given the components in the specified target container.
22Dimension minimumLayoutSize(Container parent)
Determines the minimum size of the parent container using this grid bag layout.
23Dimension preferredLayoutSize(Container parent)
Determines the preferred size of the parent container using this grid bag layout.
24void removeLayoutComponent(Component comp)
Removes the specified component from this layout.
25void setConstraints(Component comp, GridBagConstraints constraints)
Sets the constraints for the specified component in this layout.
26String toString()
Returns a string representation of this grid bag layout's values.

Methods inherited

This class inherits methods from the following classes:
  • java.lang.Object

GridBagLayout Example

Create the following java program using any editor of your choice in say D:/ > AWT > com > tutorialspoint > gui >
AwtLayoutDemo.java 
package com.tutorialspoint.gui;

import java.awt.*;
import java.awt.event.*;

public class AwtLayoutDemo {
   private Frame mainFrame;
   private Label headerLabel;
   private Label statusLabel;
   private Panel controlPanel;
   private Label msglabel;

   public AwtLayoutDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      AwtLayoutDemo  awtLayoutDemo = new AwtLayoutDemo();  
      awtLayoutDemo.showGridBagLayoutDemo();       
   }
      
   private void prepareGUI(){
      mainFrame = new Frame("Java AWT Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new Label();
      headerLabel.setAlignment(Label.CENTER);
      statusLabel = new Label();        
      statusLabel.setAlignment(Label.CENTER);
      statusLabel.setSize(350,100);

      msglabel = new Label();
      msglabel.setAlignment(Label.CENTER);
      msglabel.setText("Welcome to TutorialsPoint AWT Tutorial.");

      controlPanel = new Panel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }

   private void showGridBagLayoutDemo(){
      headerLabel.setText("Layout in action: GridBagLayout");      

      Panel panel = new Panel();
      panel.setBackground(Color.darkGray);
      panel.setSize(300,300);
      GridBagLayout layout = new GridBagLayout();

      panel.setLayout(layout);        
      GridBagConstraints gbc = new GridBagConstraints();

      gbc.fill = GridBagConstraints.HORIZONTAL;
      gbc.gridx = 0;
      gbc.gridy = 0;
      panel.add(new Button("Button 1"),gbc);

      gbc.gridx = 1;
      gbc.gridy = 0;
      panel.add(new Button("Button 2"),gbc); 

      gbc.fill = GridBagConstraints.HORIZONTAL;
      gbc.ipady = 20;   
      gbc.gridx = 0;
      gbc.gridy = 1;
      panel.add(new Button("Button 3"),gbc); 

      gbc.gridx = 1;
      gbc.gridy = 1;       
      panel.add(new Button("Button 4"),gbc);  

      gbc.gridx = 0;
      gbc.gridy = 2;      
      gbc.fill = GridBagConstraints.HORIZONTAL;
      gbc.gridwidth = 2;
      panel.add(new Button("Button 5"),gbc);  

      controlPanel.add(panel);

      mainFrame.setVisible(true);  
   }
}
Compile the program using command prompt. Go to D:/ > AWT and type the following command.
D:\AWT>javac com\tutorialspoint\gui\AwtlayoutDemo.java
If no error comes that means compilation is successful. Run the program using following command.
D:\AWT>java com.tutorialspoint.gui.AwtlayoutDemo
Verify the following output
AWT GridBagLayout

AWT Containers

Containers are integral part of AWT GUI components. A container provides a space where a component can be located. A Container in AWT is a component itself and it adds the capability to add component to itself. Following are noticable points to be considered.
  • Sub classes of Container are called as Containter. For example Panel, Frame and Window.
  • Container can add only Component to itself.
  • A default layout is present in each container which can be overridden using setLayout method.

AWT Container Class

Introduction

The class Container is the super class for the containers of AWT. Container object can contain other AWT components.

Class declaration

Following is the declaration for java.awt.Container class:
public class Container
   extends Component

Class constructors

S.N.Constructor & Description
1Container()
This creates a new Container.

Class methods

S.N.Method & Description
1Component add(Component comp)
Appends the specified component to the end of this container.
2Component add(Component comp, int index)
Adds the specified component to this container at the given position.
3void add(Component comp, Object constraints)
Adds the specified component to the end of this container.
4void add(Component comp, Object constraints, int index)
Adds the specified component to this container with the specified constraints at the specified index.
5Component add(String name, Component comp)
Adds the specified component to this container.
6void addContainerListener(ContainerListener l)
Adds the specified container listener to receive container events from this container.
7protected void addImpl(Component comp, Object constraints, int index)
Adds the specified component to this container at the specified index.
8void addNotify()
Makes this Container displayable by connecting it to a native screen resource.
9void addPropertyChangeListener(PropertyChangeListener listener)
Adds a PropertyChangeListener to the listener list.
10void addPropertyChangeListener(String propertyName, PropertyChangeListener listener)
Adds a PropertyChangeListener to the listener list for a specific property.
11void applyComponentOrientation(ComponentOrientation o)
Sets the ComponentOrientation property of this container and all components contained within it.
12boolean areFocusTraversalKeysSet(int id)
Returns whether the Set of focus traversal keys for the given focus traversal operation has been explicitly defined for this Container.
13int countComponents()
Deprecated. As of JDK version 1.1, replaced by getComponentCount().
14void deliverEvent(Event e)
Deprecated. As of JDK version 1.1, replaced by dispatchEvent(AWTEvent e)
15void doLayout()
Causes this container to lay out its components.
16Component findComponentAt(int x, int y)
Locates the visible child component that contains the specified position.
17Component findComponentAt(Point p)
Locates the visible child component that contains the specified point.
18float getAlignmentX()
Returns the alignment along the x axis.
19float getAlignmentY()
Returns the alignment along the y axis.
20Component getComponent(int n)
Gets the nth component in this container.
21Component getComponentAt(int x, int y)
Locates the component that contains the x,y position.
22Component getComponentAt(Point p)
Gets the component that contains the specified point.
23int getComponentCount()
Gets the number of components in this panel.
24Component[] getComponents()
Gets all the components in this container.
25int getComponentZOrder(Component comp)
Returns the z-order index of the component inside the container.
26ContainerListener[] getContainerListeners()
Returns an array of all the container listeners registered on this container.
27Set<AWTKeyStroke> getFocusTraversalKeys(int id)
Returns the Set of focus traversal keys for a given traversal operation for this Container.
28FocusTraversalPolicy getFocusTraversalPolicy()
Returns the focus traversal policy that will manage keyboard traversal of this Container's children, or null if this Container is not a focus cycle root.
29Insets getInsets()
Determines the insets of this container, which indicate the size of the container's border.
30LayoutManager getLayout()
Gets the layout manager for this container.
31<T extends EventListener> T[] getListeners(Class<T> listenerType)
Returns an array of all the objects currently registered as FooListeners upon this Container.
32Dimension getMaximumSize()
Returns the maximum size of this container.
33Dimension getMinimumSize()
Returns the minimum size of this container.
34Point getMousePosition(boolean allowChildren)
Returns the position of the mouse pointer in this Container's coordinate space if the Container is under the mouse pointer, otherwise returns null.
35Dimension getPreferredSize()
Returns the preferred size of this container.
36Insets insets()
Deprecated. As of JDK version 1.1, replaced by getInsets().
37void invalidate()
Invalidates the container.
38boolean isAncestorOf(Component c)
Checks if the component is contained in the component hierarchy of this container.
39boolean isFocusCycleRoot()
Returns whether this Container is the root of a focus traversal cycle.
40boolean isFocusCycleRoot(Container container)
Returns whether the specified Container is the focus cycle root of this Container's focus traversal cycle.
41boolean isFocusTraversalPolicyProvider()
Returns whether this container provides focus traversal policy.
42boolean isFocusTraversalPolicySet()
Returns whether the focus traversal policy has been explicitly set for this Container.
43void layout()
Deprecated. As of JDK version 1.1, replaced by doLayout().
44void list(PrintStream out, int indent)
Prints a listing of this container to the specified output stream.
45void list(PrintWriter out, int indent)
Prints out a list, starting at the specified indentation, to the specified print writer.
46Component locate(int x, int y)
Deprecated. As of JDK version 1.1, replaced by getComponentAt(int, int).
47Dimension minimumSize()
Deprecated. As of JDK version 1.1, replaced by getMinimumSize().
48void paint(Graphics g)
Paints the container.
49void paintComponents(Graphics g)
Paints each of the components in this container.
50protected String paramString()
Returns a string representing the state of this Container.
51Dimension preferredSize()
Deprecated. As of JDK version 1.1, replaced by getPreferredSize().
52void print(Graphics g)
Prints the container.
53void printComponents(Graphics g)
Prints each of the components in this container.
54protected void processContainerEvent(ContainerEvent e)
Processes container events occurring on this container by dispatching them to any registered ContainerListener objects.
55protected void processEvent(AWTEvent e)
Processes events on this container.
56void remove(Component comp)
Removes the specified component from this container.
57void remove(int index)
Removes the component, specified by index, from this container.
58void removeAll()
Removes all the components from this container.
59void removeContainerListener(ContainerListener l)
Removes the specified container listener so it no longer receives container events from this container.
60void removeNotify()
Makes this Container undisplayable by removing its connection to its native screen resource.
61void setComponentZOrder(Component comp, int index)
Moves the specified component to the specified z-order index in the container.
62void setFocusCycleRoot(boolean focusCycleRoot)
Sets whether this Container is the root of a focus traversal cycle.
63void setFocusTraversalKeys(int id, Set<? extends AWTKeyStroke> keystrokes)
Sets the focus traversal keys for a given traversal operation for this Container.
64void setFocusTraversalPolicy(FocusTraversalPolicy policy)
Sets the focus traversal policy that will manage keyboard traversal of this Container's children, if this Container is a focus cycle root.
65void setFocusTraversalPolicyProvider(boolean provider)
Sets whether this container will be used to provide focus traversal policy.
66void setFont(Font f)
Sets the font of this container.
67void setLayout(LayoutManager mgr)
Sets the layout manager for this container.
68void transferFocusBackward()
Transfers the focus to the previous component, as though this Component were the focus owner.
69void transferFocusDownCycle()
Transfers the focus down one focus traversal cycle.
70void update(Graphics g)
Updates the container.
71void validate()
Validates this container and all of its subcomponents.
72protected void validateTree()
Recursively descends the container tree and recomputes the layout for any subtrees marked as needing it (those marked as invalid).

Methods inherited

This class inherits methods from the following classes:
  • java.awt.Component
  • java.lang.Object

AWT Panel Class

Introduction

The class Panel is the simplest container class. It provides space in which an application can attach any other component, including other panels. It uses FlowLayout as default layout manager.

Class declaration

Following is the declaration for java.awt.Panel class:
public class Panel
   extends Container
      implements Accessible

Class constructors

S.N.Constructor & Description
1Panel()
Creates a new panel using the default layout manager.
2Panel(LayoutManager layout)
Creates a new panel with the specified layout manager.

Class methods

S.N.Method & Description
1void addNotify()
Creates the Panel's peer.
2AccessibleContext getAccessibleContext()
Gets the AccessibleContext associated with this Panel.

Methods inherited

This class inherits methods from the following classes:
  • java.awt.Container
  • java.awt.Component
  • java.lang.Object

Panel Example

Create the following java program using any editor of your choice in say D:/ > AWT > com > tutorialspoint > gui >
AwtContainerDemo.java 
package com.tutorialspoint.gui;

import java.awt.*;
import java.awt.event.*;

public class AwtContainerDemo {
   private Frame mainFrame;
   private Label headerLabel;
   private Label statusLabel;
   private Panel controlPanel;
   private Label msglabel;

   public AwtContainerDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      AwtContainerDemo  awtContainerDemo = new AwtContainerDemo();          
      awtContainerDemo.showPanelDemo();
   }

   private void prepareGUI(){
      mainFrame = new Frame("Java AWT Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new Label();
      headerLabel.setAlignment(Label.CENTER);
      statusLabel = new Label();        
      statusLabel.setAlignment(Label.CENTER);
      statusLabel.setSize(350,100);
   
      msglabel = new Label();
      msglabel.setAlignment(Label.CENTER);
      msglabel.setText("Welcome to TutorialsPoint AWT Tutorial.");

      controlPanel = new Panel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }

   private void showPanelDemo(){
      headerLabel.setText("Container in action: Panel");      

      Panel panel = new Panel();
      panel.setBackground(Color.magenta);
      panel.setLayout(new FlowLayout());        
      panel.add(msglabel);

      controlPanel.add(panel);

      mainFrame.setVisible(true);  
   }
}
Compile the program using command prompt. Go to D:/ > AWT and type the following command.
D:\AWT>javac com\tutorialspoint\gui\AwtContainerDemo.java
If no error comes that means compilation is successful. Run the program using following command.
D:\AWT>java com.tutorialspoint.gui.AwtContainerDemo
Verify the following output
AWT Panel

AWT Frame Class

Introduction

The class Frame is a top level window with border and title. It uses BorderLayout as default layout manager.

Class declaration

Following is the declaration for java.awt.Frame class:
public class Frame
   extends Window
      implements MenuContainer

Field

Following are the fields for java.awt.Frame class:
  • static float BOTTOM_ALIGNMENT -- Ease-of-use constant for getAlignmentY.
  • static int CROSSHAIR_CURSOR -- Deprecated. replaced by Cursor.CROSSHAIR_CURSOR.
  • static int DEFAULT_CURSOR -- Deprecated. replaced by Cursor.DEFAULT_CURSOR.
  • static int E_RESIZE_CURSOR -- Deprecated. replaced by Cursor.E_RESIZE_CURSOR.
  • static int HAND_CURSOR -- Deprecated. replaced by Cursor.HAND_CURSOR.
  • static int ICONIFIED -- This state bit indicates that frame is iconified.
  • static int MAXIMIZED_BOTH -- This state bit mask indicates that frame is fully maximized (that is both horizontally and vertically).
  • static int MAXIMIZED_HORIZ -- This state bit indicates that frame is maximized in the horizontal direction.
  • static int MAXIMIZED_VERT -- This state bit indicates that frame is maximized in the vertical direction.
  • static int MOVE_CURSOR -- Deprecated. replaced by Cursor.MOVE_CURSOR.
  • static int N_RESIZE_CURSOR -- Deprecated. replaced by Cursor.N_RESIZE_CURSOR.
  • static int NE_RESIZE_CURSOR -- Deprecated. replaced by Cursor.NE_RESIZE_CURSOR.
  • static int NORMAL -- Frame is in the "normal" state.
  • static int NW_RESIZE_CURSOR -- Deprecated. replaced by Cursor.NW_RESIZE_CURSOR.
  • static int S_RESIZE_CURSOR -- Deprecated. replaced by Cursor.S_RESIZE_CURSOR.
  • static int SE_RESIZE_CURSOR -- Deprecated. replaced by Cursor.SE_RESIZE_CURSOR.
  • static int SW_RESIZE_CURSOR -- Deprecated. replaced by Cursor.SW_RESIZE_CURSOR.
  • static int TEXT_CURSOR -- Deprecated. replaced by Cursor.TEXT_CURSOR.
  • static int W_RESIZE_CURSOR -- Deprecated. replaced by Cursor.W_RESIZE_CURSOR.
  • static int WAIT_CURSOR -- Deprecated. replaced by Cursor.WAIT_CURSOR.

Class constructors

S.N.Constructor & Description
1Frame()
Constructs a new instance of Frame that is initially invisible.
2Frame(GraphicsConfiguration gc)
Constructs a new, initially invisible Frame with the specified GraphicsConfiguration.
3Frame(String title)
Constructs a new, initially invisible Frame object with the specified title.
4Frame(String title, GraphicsConfiguration gc)
Constructs a new, initially invisible Frame object with the specified title and a GraphicsConfiguration.

Class methods

S.N.Method & Description
1void addNotify()
Makes this Frame displayable by connecting it to a native screen resource.
2AccessibleContext getAccessibleContext()
Gets the AccessibleContext associated with this Frame.
3int getCursorType()
Deprecated. As of JDK version 1.1, replaced by Component.getCursor().
4int getExtendedState()
Gets the state of this frame.
5static Frame[] getFrames()
Returns an array of all Frames created by this application.
6Image getIconImage()
Returns the image to be displayed as the icon for this frame.
7Rectangle getMaximizedBounds()
Gets maximized bounds for this frame.
8MenuBar getMenuBar()
Gets the menu bar for this frame.
9int getState()
Gets the state of this frame (obsolete).
10String getTitle()
Gets the title of the frame.
11boolean isResizable()
Indicates whether this frame is resizable by the user.
12boolean isUndecorated()
Indicates whether this frame is undecorated.
13protected String paramString()
Returns a string representing the state of this Frame.
14void remove(MenuComponent m)
Removes the specified menu bar from this frame.
15void removeNotify()
Makes this Frame undisplayable by removing its connection to its native screen resource.
16void setCursor(int cursorType)
Deprecated. As of JDK version 1.1, replaced by Component.setCursor(Cursor).
17void setExtendedState(int state)
Sets the state of this frame.
18void setIconImage(Image image)
Sets the image to be displayed as the icon for this window.
19void setMaximizedBounds(Rectangle bounds)
Sets the maximized bounds for this frame.
20void setMenuBar(MenuBar mb)
Sets the menu bar for this frame to the specified menu bar.
21void setResizable(boolean resizable)
Sets whether this frame is resizable by the user.
22void setState(int state)
Sets the state of this frame (obsolete).
23void setTitle(String title)
Sets the title for this frame to the specified string.
24void setUndecorated(boolean undecorated)
Disables or enables decorations for this frame.

Methods inherited

This class inherits methods from the following classes:
  • java.awt.Window
  • java.awt.Container
  • java.awt.Component
  • java.lang.Object

Frame Example

Create the following java program using any editor of your choice in say D:/ > AWT > com > tutorialspoint > gui >
AwtContainerDemo.java 
package com.tutorialspoint.gui;

import java.awt.*;
import java.awt.event.*;

public class AwtContainerDemo {
   private Frame mainFrame;
   private Label headerLabel;
   private Label statusLabel;
   private Panel controlPanel;
   private Label msglabel;

   public AwtContainerDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      AwtContainerDemo  awtContainerDemo = new AwtContainerDemo();          
      awtContainerDemo.showFrameDemo();
   }

   private void prepareGUI(){
      mainFrame = new Frame("Java AWT Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new Label();
      headerLabel.setAlignment(Label.CENTER);
      statusLabel = new Label();        
      statusLabel.setAlignment(Label.CENTER);
      statusLabel.setSize(350,100);
   
      msglabel = new Label();
      msglabel.setAlignment(Label.CENTER);
      msglabel.setText("Welcome to TutorialsPoint AWT Tutorial.");

      controlPanel = new Panel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }
   
   private void showFrameDemo(){
      headerLabel.setText("Container in action: Frame");   

      final Frame frame = new Frame();
      frame.setSize(300, 300);
      frame.setLayout(new FlowLayout());       
      frame.add(msglabel);
      frame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            frame.dispose();
         }        
      });    
      Button okButton = new Button("Open a Frame");

      okButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            statusLabel.setText("A Frame shown to the user.");
            frame.setVisible(true);
         }
      });
      controlPanel.add(okButton);

      mainFrame.setVisible(true);  
   }
}
Compile the program using command prompt. Go to D:/ > AWT and type the following command.
D:\AWT>javac com\tutorialspoint\gui\AwtContainerDemo.java
If no error comes that means compilation is successful. Run the program using following command.
D:\AWT>java com.tutorialspoint.gui.AwtContainerDemo
Verify the following output
AWT Frame

AWT Window Class

Introduction

The class Window is a top level window with no border and no menubar. It uses BorderLayout as default layout manager.

Class declaration

Following is the declaration for java.awt.Window class:
public class Window
   extends Container
      implements Accessible

Class constructors

S.N.Constructor & Description
1Window(Frame owner)
Constructs a new, initially invisible window with the specified Frame as its owner.
2Window(Window owner)
Constructs a new, initially invisible window with the specified Window as its owner.
3Window(Window owner, GraphicsConfiguration gc)
Constructs a new, initially invisible window with the specified owner Window and a GraphicsConfiguration of a screen device.

Class methods

S.N.Method & Description
1void addNotify()
Makes this Window displayable by creating the connection to its native screen resource.
2void addPropertyChangeListener(PropertyChangeListener listener)
Adds a PropertyChangeListener to the listener list.
3void addPropertyChangeListener(String propertyName, PropertyChangeListener listener)
Adds a PropertyChangeListener to the listener list for a specific property.
4void addWindowFocusListener(WindowFocusListener l)
Adds the specified window focus listener to receive window events from this window.
5void addWindowListener(WindowListener l)
Adds the specified window listener to receive window events from this window.
6void addWindowStateListener(WindowStateListener l)
Adds the specified window state listener to receive window events from this window.
7void applyResourceBundle(ResourceBundle rb)
Deprecated. As of J2SE 1.4, replaced by Component.applyComponentOrientation.
8void applyResourceBundle(String rbName)
Deprecated. As of J2SE 1.4, replaced by Component.applyComponentOrientation.
9void createBufferStrategy(int numBuffers)
Creates a new strategy for multi-buffering on this component.
10void createBufferStrategy(int numBuffers, BufferCapabilities caps)
Creates a new strategy for multi-buffering on this component with the required buffer capabilities.
11void dispose()
Releases all of the native screen resources used by this Window, its subcomponents, and all of its owned children.
12AccessibleContext getAccessibleContext()
Gets the AccessibleContext associated with this Window.
13BufferStrategy getBufferStrategy()
Returns the BufferStrategy used by this component.
14boolean getFocusableWindowState()
Returns whether this Window can become the focused Window if it meets the other requirements outlined in isFocusableWindow.
15Container getFocusCycleRootAncestor()
Always returns null because Windows have no ancestors; they represent the top of the Component hierarchy.
16Component getFocusOwner()
Returns the child Component of this Window that has focus if this Window is focused; returns null otherwise.
17Set<AWTKeyStroke> getFocusTraversalKeys(int id)
Gets a focus traversal key for this Window.
18GraphicsConfiguration getGraphicsConfiguration()
This method returns the GraphicsConfiguration used by this Window.
19List<Image> getIconImages()
Returns the sequence of images to be displayed as the icon for this window.
20InputContext getInputContext()
Gets the input context for this window.
21<T extends EventListener> T[] getListeners(Class<T> listenerType)
Returns an array of all the objects currently registered as FooListeners upon this Window.
22Locale getLocale()
Gets the Locale object that is associated with this window, if the locale has been set.
23Dialog.ModalExclusionType getModalExclusionType()
Returns the modal exclusion type of this window.
24Component getMostRecentFocusOwner()
Returns the child Component of this Window that will receive the focus when this Window is focused.
25Window[] getOwnedWindows()
Return an array containing all the windows this window currently owns.
26Window getOwner()
Returns the owner of this window.
27static Window[] getOwnerlessWindows()
Returns an array of all Windows created by this application that have no owner.
28Toolkit getToolkit()
Returns the toolkit of this frame.
29String getWarningString()
Gets the warning string that is displayed with this window.
30WindowFocusListener[] getWindowFocusListeners()
Returns an array of all the window focus listeners registered on this window.
31WindowListener[] getWindowListeners()
Returns an array of all the window listeners registered on this window.
32static Window[] getWindows()
Returns an array of all Windows, both owned and ownerless, created by this application.
33WindowStateListener[] getWindowStateListeners()
Returns an array of all the window state listeners registered on this window.
34void hide()
Deprecated. As of JDK version 1.5, replaced by setVisible(boolean).
35boolean isActive()
Returns whether this Window is active.
36boolean isAlwaysOnTop()
Returns whether this window is an always-on-top window.
37boolean isAlwaysOnTopSupported()
Returns whether the always-on-top mode is supported for this window.
38boolean isFocusableWindow()
Returns whether this Window can become the focused Window, that is, whether this Window or any of its subcomponents can become the focus owner.
39boolean isFocusCycleRoot()
Always returns true because all Windows must be roots of a focus traversal cycle.
40boolean isFocused()
Returns whether this Window is focused.
41boolean isLocationByPlatform()
Returns true if this Window will appear at the default location for the native windowing system the next time this Window is made visible.
42boolean isShowing()
Checks if this Window is showing on screen.
43void pack()
Causes this Window to be sized to fit the preferred size and layouts of its subcomponents.
44void paint(Graphics g)
Paints the container.
45boolean postEvent(Event e)
Deprecated. As of JDK version 1.1 replaced by dispatchEvent(AWTEvent).
46protected void processEvent(AWTEvent e)
Processes events on this window.
47protected void processWindowEvent(WindowEvent e)
Processes window events occurring on this window by dispatching them to any registered WindowListener objects.
48protected void processWindowFocusEvent(WindowEvent e)
Processes window focus event occuring on this window by dispatching them to any registered WindowFocusListener objects.
49protected void processWindowStateEvent(WindowEvent e)
Processes window state event occuring on this window by dispatching them to any registered WindowStateListener objects.
50void removeNotify()
Makes this Container undisplayable by removing its connection to its native screen resource.
51void removeWindowFocusListener(WindowFocusListener l)
Removes the specified window focus listener so that it no longer receives window events from this window.
52void removeWindowListener(WindowListener l)
Removes the specified window listener so that it no longer receives window events from this window.
53void removeWindowStateListener(WindowStateListener l)
Removes the specified window state listener so that it no longer receives window events from this window.
54void reshape(int x, int y, int width, int height)
Deprecated. As of JDK version 1.1, replaced by setBounds(int, int, int, int).
55void setAlwaysOnTop(boolean alwaysOnTop)
Sets whether this window should always be above other windows.
56void setBounds(int x, int y, int width, int height)
Moves and resizes this component.
57void setBounds(Rectangle r)
Moves and resizes this component to conform to the new bounding rectangle r.
58void setCursor(Cursor cursor)
Set the cursor image to a specified cursor.
59void setFocusableWindowState(boolean focusableWindowState)
Sets whether this Window can become the focused Window if it meets the other requirements outlined in isFocusableWindow.
60void setFocusCycleRoot(boolean focusCycleRoot)
Does nothing because Windows must always be roots of a focus traversal cycle.
61void setIconImage(Image image)
Sets the image to be displayed as the icon for this window.
62void setIconImages(List<? extends Image> icons)
Sets the sequence of images to be displayed as the icon for this window.
63void setLocationByPlatform(boolean locationByPlatform)
Sets whether this Window should appear at the default location for the native windowing system or at the current location (returned by getLocation) the next time the Window is made visible.
64void setLocationRelativeTo(Component c)
Sets the location of the window relative to the specified component.
65void setMinimumSize(Dimension minimumSize)
Sets the minimum size of this window to a constant value.
66void setModalExclusionType(Dialog.ModalExclusionType exclusionType)
Specifies the modal exclusion type for this window.
67void setSize(Dimension d)
Resizes this component so that it has width d.width and height d.height.
68void setSize(int width, int height)
Resizes this component so that it has width width and height height.
69void setVisible(boolean b)
Shows or hides this Window depending on the value of parameter b.
70void show()
Deprecated. As of JDK version 1.5, replaced by setVisible(boolean).
71void toBack()
If this Window is visible, sends this Window to the back and may cause it to lose focus or activation if it is the focused or active Window.
72void toFront()
If this Window is visible, brings this Window to the front and may make it the focused Window.

Methods inherited

This class inherits methods from the following classes:
  • java.awt.Window
  • java.awt.Container
  • java.awt.Component
  • java.lang.Object

Window Example

Create the following java program using any editor of your choice in say D:/ > AWT > com > tutorialspoint > gui >
AwtContainerDemo.java 
package com.tutorialspoint.gui;

import java.awt.*;
import java.awt.event.*;

public class AwtContainerDemo {
   private Frame mainFrame;
   private Label headerLabel;
   private Label statusLabel;
   private Panel controlPanel;
   private Label msglabel;

   public AwtContainerDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      AwtContainerDemo  awtContainerDemo = new AwtContainerDemo();          
      awtContainerDemo.showFrameDemo();
   }

   private void prepareGUI(){
      mainFrame = new Frame("Java AWT Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new Label();
      headerLabel.setAlignment(Label.CENTER);
      statusLabel = new Label();        
      statusLabel.setAlignment(Label.CENTER);
      statusLabel.setSize(350,100);
   
      msglabel = new Label();
      msglabel.setAlignment(Label.CENTER);
      msglabel.setText("Welcome to TutorialsPoint AWT Tutorial.");

      controlPanel = new Panel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }
   
   private void showWindowDemo(){
      headerLabel.setText("Container in action: Window");   
      final MessageWindow window = 
         new MessageWindow(mainFrame,
         "Welcome to TutorialsPoint AWT Tutorial.");

      Button okButton = new Button("Open a Window");
      okButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            window.setVisible(true);
            statusLabel.setText("A Window shown to the user.");                
         }
      });
      controlPanel.add(okButton);
      mainFrame.setVisible(true);  
   }

   class MessageWindow extends Window{
      private String message; 

      public MessageWindow(Frame parent, String message) { 
         super(parent);               
         this.message = message; 
         setSize(300, 300);       
         setLocationRelativeTo(parent);
         setBackground(Color.gray);
      }

      public void paint(Graphics g) { 
         super.paint(g);
         g.drawRect(0,0,getSize().width - 1,getSize().height - 1); 
         g.drawString(message,50,150); 
      } 
   }
}
Compile the program using command prompt. Go to D:/ > AWT and type the following command.
D:\AWT>javac com\tutorialspoint\gui\AwtContainerDemo.java
If no error comes that means compilation is successful. Run the program using following command.
D:\AWT>java com.tutorialspoint.gui.AwtContainerDemo
Verify the following output
AWT Window
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