What actionlistener in java

Drag and Drop is a direct manipulation gesture found in many Graphical User Interface systems that provides a mechanism to transfer information between two entities logically associated with presentation elements in the GUI.

Provides a set of «lightweight» (all-Java language) components that, to the maximum degree possible, work the same on all platforms.

Provides user interface objects built according to the Java look and feel (once codenamed Metal), which is the default look and feel.

Uses of ActionListener in java.awt

AWTEventMulticaster implements efficient and thread-safe multi-cast event dispatching for the AWT events defined in the java.awt.event package.

Removes the specified action listener so that it no longer receives action events from this text field.

Uses of ActionListener in java.awt.dnd

Uses of ActionListener in javax.swing

The Action interface provides a useful extension to the ActionListener interface in cases where the same functionality may be accessed by several controls.

Creates and returns a new dialog containing the specified ColorChooser pane along with «OK», «Cancel», and «Reset» buttons.

This method is now obsolete, please use a combination of getActionMap() and getInputMap() for similar behavior.

Removes the specified action listener so that it no longer receives action events from this textfield.

Creates a Timer and initializes both the initial delay and between-event delay to delay milliseconds.

Uses of ActionListener in javax.swing.plaf.basic

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How to Write an Action Listener

Action listeners are probably the easiest — and most common — event handlers to implement. You implement an action listener to define what should be done when an user performs certain operation.

An action event occurs, whenever an action is performed by the user. Examples: When the user clicks a button, chooses a menu item, presses Enter in a text field. The result is that an actionPerformed message is sent to all action listeners that are registered on the relevant component.

To write an Action Listener, follow the steps given below:

public class MyClass implements ActionListener 
someComponent.addActionListener(instanceOfMyClass);
 public void actionPerformed(ActionEvent e) < . //code that reacts to the action. >
 In general, to detect when the user clicks an onscreen button (or does the keyboard equivalent), a program must have an object that implements the ActionListener interface. The program must register this object as an action listener on the button (the event source), using the addActionListener method. When the user clicks the onscreen button, the button fires an action event. This results in the invocation of the action listener's actionPerformed method (the only method in the ActionListener interface). The single argument to the method is an ActionEvent object that gives information about the event and its source.
 Let us write a simple program which displays how many number of times a button is clicked by the user. First, here is the code that sets up the TextField , button and numClicks variable:
 public class AL extends Frame implements WindowListener,ActionListener < TextField text = new TextField(20); Button b; private int numClicks = 0;
 In the above example, the event handler class is AL which implements ActionListener.
 We would like to handle the button-click event, so we add an action listener to the button b as below:
 b = new Button("Click me"); b.addActionListener(this);
 In the above code, Button b is a component upon which an instance of event handler class AL is registered.
 Now, we want to display the text as to how many number of times a user clicked button. We can do this by writing the code as below:
 public void actionPerformed(ActionEvent e) < numClicks++; text.setText("Button Clicked " + numClicks + " times");
 Now, when the user clicks the Button b, the button fires an action event which invokes the action listener's actionPerformed method. Each time the user presses the button, numClicks variable is appended and the message is displayed in the text field.
 Here is the complete program(AL.java):
 import java.awt.*; import java.awt.event.*; public class AL extends Frame implements WindowListener,ActionListener < TextField text = new TextField(20); Button b; private int numClicks = 0; public static void main(String[] args) < AL myWindow = new AL("My first window"); myWindow.setSize(350,100); myWindow.setVisible(true); >public AL(String title) < super(title); setLayout(new FlowLayout()); addWindowListener(this); b = new Button("Click me"); add(b); add(text); b.addActionListener(this); >public void actionPerformed(ActionEvent e) < numClicks++; text.setText("Button Clicked " + numClicks + " times"); >public void windowClosing(WindowEvent e) < dispose(); System.exit(0); >public void windowOpened(WindowEvent e) <> public void windowActivated(WindowEvent e) <> public void windowIconified(WindowEvent e) <> public void windowDeiconified(WindowEvent e) <> public void windowDeactivated(WindowEvent e) <> public void windowClosed(WindowEvent e) <> >
 More Examples: Beeper program example is available in this trail's introduction to events, Introduction to Event Listeners. You can find the entire program in Beeper.java . The other example described in that section, MultiListener.java , has two action sources and two action listeners, with one listener listening to both sources and the other listening to just one.
 The Action Listener API
 Because ActionListener has only one method, it has no corresponding adapter class.
   Method  Purpose  
  actionPerformed(actionEvent)  Called just after the user performs an action.  
 
 actionEvent.getModifiers() & ActionEvent.SHIFT_MASK
 Examples that Use Action Listeners
 The following table lists some of the many examples that use action listeners.
   Example  Where Described  Notes  
   Beeper  This section and Introduction to Event Listeners  Contains one button with one action listener that beeps when you click the button.  
   MultiListener  Introduction to Event Listeners  Registers two different action listeners on one button. Also registers the same action listener on two different buttons.  
   RadioButtonDemo  How to Use Radio Buttons  Registers the same action listener on five radio buttons. The listener uses the getActionCommand method to determine which radio button fired the event.  
   MenuDemo  How to Use Menus  Shows how to listen for action events on menu items.  
   TextDemo  How to Use Text Fields  An applet that registers an action listener on a text field.  
   IconDemo  How to Use Icons  Loads an image in an action listener. Because loading an image can take a while, this program uses a SwingWorker to load the image in a background thread.  
   TableDialogEditDemo  How to Use Tables  Registers an action listener through a factory method on the OK button of a color chooser dialog.  
   SliderDemo  How to Use Sliders  Registers an action listener on a timer that controls an animation loop.  
 
 Previous page: Implementing Listeners for Commonly Handled Events 
Next page: How to Write a Caret Listener
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 What actionlistener in java
 Interface ActionListener
  All Superinterfaces: EventListener All Known Subinterfaces: Action All Known Implementing Classes: AbstractAction , AWTEventMulticaster , BasicDesktopPaneUI.CloseAction , BasicDesktopPaneUI.MaximizeAction , BasicDesktopPaneUI.MinimizeAction , BasicDesktopPaneUI.NavigateAction , BasicDesktopPaneUI.OpenAction , BasicFileChooserUI.ApproveSelectionAction , BasicFileChooserUI.CancelSelectionAction , BasicFileChooserUI.ChangeToParentDirectoryAction , BasicFileChooserUI.GoHomeAction , BasicFileChooserUI.NewFolderAction , BasicFileChooserUI.UpdateAction , BasicInternalFrameTitlePane.CloseAction , BasicInternalFrameTitlePane.IconifyAction , BasicInternalFrameTitlePane.MaximizeAction , BasicInternalFrameTitlePane.MoveAction , BasicInternalFrameTitlePane.RestoreAction , BasicInternalFrameTitlePane.SizeAction , BasicOptionPaneUI.ButtonActionListener , BasicScrollBarUI.ScrollListener , BasicSliderUI.ActionScroller , BasicSliderUI.ScrollListener , BasicSplitPaneUI.KeyboardDownRightHandler , BasicSplitPaneUI.KeyboardEndHandler , BasicSplitPaneUI.KeyboardHomeHandler , BasicSplitPaneUI.KeyboardResizeToggleHandler , BasicSplitPaneUI.KeyboardUpLeftHandler , BasicTreeUI.ComponentHandler , BasicTreeUI.TreeCancelEditingAction , BasicTreeUI.TreeHomeAction , BasicTreeUI.TreeIncrementAction , BasicTreeUI.TreePageAction , BasicTreeUI.TreeToggleAction , BasicTreeUI.TreeTraverseAction , DefaultCellEditor.EditorDelegate , DefaultEditorKit.BeepAction , DefaultEditorKit.CopyAction , DefaultEditorKit.CutAction , DefaultEditorKit.DefaultKeyTypedAction , DefaultEditorKit.InsertBreakAction , DefaultEditorKit.InsertContentAction , DefaultEditorKit.InsertTabAction , DefaultEditorKit.PasteAction , DefaultTreeCellEditor , DropTarget.DropTargetAutoScroller , FormView , HTMLEditorKit.HTMLTextAction , HTMLEditorKit.InsertHTMLTextAction , JComboBox , List.AccessibleAWTList , MetalFileChooserUI.DirectoryComboBoxAction , StyledEditorKit.AlignmentAction , StyledEditorKit.BoldAction , StyledEditorKit.FontFamilyAction , StyledEditorKit.FontSizeAction , StyledEditorKit.ForegroundAction , StyledEditorKit.ItalicAction , StyledEditorKit.StyledTextAction , StyledEditorKit.UnderlineAction , TextAction , ToolTipManager.insideTimerAction , ToolTipManager.outsideTimerAction , ToolTipManager.stillInsideTimerAction
 
 The listener interface for receiving action events. The class that is interested in processing an action event implements this interface, and the object created with that class is registered with a component, using the component's addActionListener method. When the action event occurs, that object's actionPerformed method is invoked.
 Method Summary
 Method Detail
 actionPerformed
 Report a bug or suggest an enhancement 
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