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<TITLE>Creating an Action (Java Developers Almanac Example)
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<B><A HREF="../javax.swing/pkg.html#Actions">Actions</A></B><font color="#666666" class="xsmall-font">
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<h3>e855. Creating an Action</h3>
An action is used by a Swing component to invoke a method. To create
an action, the <code>actionPerformed()</code> method must be overridden. The
action is then attached to a component such as a button or bound to a
keystroke in a text component. When the button is activated or the
keystroke is pressed, the action's <code>actionPerformed()</code> method is
called. Actions can be attached to more than one component or
keystroke.
<P> Actions can also contain other optional information, such as a
label, icon, or tool tip text. When the action is attached to a
component, the component may use this information if present. For
example, if the action has a label and icon, a button created using
that action will use that label and icon.
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This example defines an action and creates a button using the action.
<pre> // Create an action object
public Action action = new AbstractAction(<font color="#0066ff"><i>"Action Name"</i></font>) {
// This is an instance initializer; it is executed just after the
// constructor of the superclass is invoked
{
// The following values are completely optional
// Set tool tip text
putValue(Action.SHORT_DESCRIPTION, <font color="#0066ff"><i>"Tool Tip Text"</i></font>);
// This text is not directly used by any Swing component;
// however, this text could be used in a help system
putValue(Action.LONG_DESCRIPTION, <font color="#0066ff"><i>"Context-Sensitive Help Text"</i></font>);
// Set an icon
Icon icon = new ImageIcon(<font color="#0066ff"><i>"icon.gif"</i></font>);
putValue(Action.SMALL_ICON, icon);
// Set a mnemonic character. In most look and feels, this causes the
// specified character to be underlined This indicates that if the component
// using this action has the focus and In some look and feels, this causes
// the specified character in the label to be underlined and
putValue(Action.MNEMONIC_KEY, new Integer(java.awt.event.KeyEvent.<font color="#0066ff"><i>VK_A</i></font>));
// Set an accelerator key; this value is used by menu items
putValue(Action.ACCELERATOR_KEY, KeyStroke.getKeyStroke("control F2"));
}
// This method is called when the action is invoked
public void actionPerformed(ActionEvent evt) {
// Perform action
}
};
</pre>
Create a button using the action object:
<pre> JButton button = new JButton(action);
</pre>
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<b>Related Examples</b></font></td>
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e856. <a class="eglink" href="ListActions.html?l=rel">
Listing the Actions in a Component
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e857. <a class="eglink" href="EnableAction.html?l=rel">
Enabling an Action
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See also:
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#JButton">
JButton
</a>
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#JCheckBox">
JCheckBox
</a>
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#JComboBox">
JComboBox
</a>
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#JDesktop%20and%20JInternalFrame">
JDesktop and JInternalFrame
</a>
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#JFrame,%20JWindow,%20JDialog">
JFrame, JWindow, JDialog
</a>
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#JLabel">
JLabel
</a>
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#JList">
JList
</a>
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#JProgressBar">
JProgressBar
</a>
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#JRadioButton">
JRadioButton
</a>
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#JScrollPane">
JScrollPane
</a>
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#JSlider">
JSlider
</a>
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#JSpinner">
JSpinner
</a>
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#JSplitPane">
JSplitPane
</a>
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#JTabbedPane">
JTabbedPane
</a>
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#JToolBar">
JToolBar
</a>
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#Keystrokes%20and%20Input%20Maps">
Keystrokes and Input Maps
</a>
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#Layout">
Layout
</a>
<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#Look%20and%20Feel">
Look and Feel
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<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#Menus">
Menus
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<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#Progress%20Monitor">
Progress Monitor
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<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#The%20Screen">
The Screen
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<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#Tool%20Tips">
Tool Tips
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<a class="eglink" href="/egs/javax.swing/pkg.html?l=rel#UI%20Default%20Values">
UI Default Values
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