With this example we shall show you how to work with Action class in Java. In many ways the use of the Action class is pretty much the same as the use of the ActionListener interface.
With Action class you can monitor a number of events in a component and customize the behavior of your application when a specific event occurs. The action class is very flexible because you can construct a number of classes that extend AbstractAction and customize your own Action and your own events you wish to monitor.
Basically, all you have to do in order to work with Action class is:
- Create a number of classes that extend the
AbstractActionclass. - Override the
actionPerformedto customize the handling of a specific event. - Use the
putValuemethod to set the specific values of different parameters to further customize the events you want to handle.
Let’s see the code snippets that follow:
001 002 003 004 005 006 007 008 009 010 011 012 013 014 015 016 017 018 019 020 021 022 023 024 025 026 027 028 029 030 031 032 033 034 035 036 037 038 039 040 041 042 043 044 045 046 047 048 049 050 051 052 053 054 055 056 057 058 059 060 061 062 063 064 065 066 067 068 069 070 071 072 073 074 075 076 077 078 079 080 081 082 083 084 085 086 087 088 089 090 091 092 093 094 095 096 097 098 099 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 | package com.javacodegeeks.snippets.desktop;import java.awt.BorderLayout;import java.awt.Font;import java.awt.GridLayout;import java.awt.event.ActionEvent;import java.awt.event.KeyEvent;import javax.swing.AbstractAction;import javax.swing.Action;import javax.swing.BorderFactory;import javax.swing.ImageIcon;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JMenu;import javax.swing.JMenuBar;import javax.swing.JMenuItem;import javax.swing.JPanel;public class Main extends JFrame { private int gotoChannel = 5; private JLabel channelLabel = new JLabel(); public static final int Min_Channel = 2; private int curr_chanel = Min_Channel; private Action incrAction = new Increase(); public static final int MAX_CHANNEL = 20; private Action decrAction = new Decrese(); private GotoAction gotoAction = new GotoAction(); private Action setGoToAction = new SetGoToAction(); public class Increase extends AbstractAction { public Increase() {putValue(NAME, "Increase");putValue(SHORT_DESCRIPTION, "Increment the number");putValue(MNEMONIC_KEY, new Integer(KeyEvent.VK_U)); } @Override public void actionPerformed(ActionEvent ae) {setChannel(curr_chanel + 1); } } public class Decrese extends AbstractAction { public Decrese() {putValue(NAME, "Decrease");putValue(SHORT_DESCRIPTION, "Decrement the number");putValue(MNEMONIC_KEY, new Integer(KeyEvent.VK_D)); } @Override public void actionPerformed(ActionEvent ae) {setChannel(curr_chanel - 1); } } public class GotoAction extends AbstractAction { public GotoAction() {putValue(MNEMONIC_KEY, new Integer(KeyEvent.VK_G));update(); } public void update() {putValue(NAME, "Go to " + gotoChannel);putValue(SHORT_DESCRIPTION, "Change to " + gotoChannel); } @Override public void actionPerformed(ActionEvent ae) {setChannel(gotoChannel); } } public class SetGoToAction extends AbstractAction { public SetGoToAction() {putValue(NAME, "Set 'Go to' number");putValue(SHORT_DESCRIPTION,"Make current number the goto channel");putValue(MNEMONIC_KEY, new Integer(KeyEvent.VK_S)); } @Override public void actionPerformed(ActionEvent ae) {gotoChannel = curr_chanel;gotoAction.update();setEnabled(false);gotoAction.setEnabled(false); } } public Main() { super(""); setChannel(curr_chanel); channelLabel.setHorizontalAlignment(JLabel.CENTER); channelLabel.setFont(new Font("Serif", Font.PLAIN, 42)); getContentPane().add(channelLabel, BorderLayout.NORTH); JPanel buttonPanel = new JPanel(new GridLayout(4, 4, 36, 66)); buttonPanel.setBorder(BorderFactory.createEmptyBorder(6, 16, 16, 16)); getContentPane().add(buttonPanel, BorderLayout.CENTER); buttonPanel.add(new JButton(incrAction)); buttonPanel.add(new JButton(gotoAction)); buttonPanel.add(new JButton(decrAction)); buttonPanel.add(new JButton(setGoToAction)); JMenuBar menuBar = new JMenuBar(); JMenu menu = new JMenu("Number"); menu.add(new JMenuItem(incrAction)); menu.add(new JMenuItem(decrAction)); menu.addSeparator(); menu.add(new JMenuItem(gotoAction)); menu.add(new JMenuItem(setGoToAction)); menuBar.add(menu); setJMenuBar(menuBar); } public void setChannel(int chan) { curr_chanel = chan; channelLabel.setText("Number is: " + curr_chanel); decrAction.setEnabled(curr_chanel > Min_Channel); incrAction.setEnabled(curr_chanel < MAX_CHANNEL); gotoAction.setEnabled(curr_chanel != gotoChannel); setGoToAction.setEnabled(curr_chanel != gotoChannel); } public static void main(String argv[]) { JFrame Jframe = new Main(); Jframe.setSize(800, 600); Jframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); Jframe.setVisible(true); }} |
This was an example on how to use the Action class in Java.
