In this tutorial we are going to create a simple application that displays all the occurring events that might take place in a Java Desktop Application. You might find this particularly useful when developing your own applications and you want to fully control the events that occur and give proper feedback to the user. You can also customize the behavior of your application according to the occurrence of a specific event. For example you might want your application to behave differently according to witch button the user presses.
In short in order to display and handle all the occurring events, one should follows these steps:
- Create a
HashMapthat will hold all the events that you might want to monitor. - Create a String array with all the events you want to monitor.
- Create a
FocusListenerand override thefocusGainedandfocusLostmethods. - Create a
KeyListenerand override thekeyPressed,keyReleasedandkeyTypedmethods to monitor keyboard activity. - Create a
MouseListenerand overridemouseClicked,mouseEntered,mouseExited,mousePressed,mouseReleasedto monitor mouse activity. - Create a
MouseMotionListenerand overridemouseDragged,mouseMovedmethod to monitor mouse movements.
Let’s see the code snippet that follows:
001 002 003 004 005 006 007 008 009 010 011 012 013 014 015 016 017 018 019 020 021 022 023 024 025 026 027 028 029 030 031 032 033 034 035 036 037 038 039 040 041 042 043 044 045 046 047 048 049 050 051 052 053 054 055 056 057 058 059 060 061 062 063 064 065 066 067 068 069 070 071 072 073 074 075 076 077 078 079 080 081 082 083 084 085 086 087 088 089 090 091 092 093 094 095 096 097 098 099 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 | package com.javacodegeeks.snippets.desktop;import java.awt.Color;import java.awt.Container;import java.awt.GridLayout;import java.awt.event.FocusEvent;import java.awt.event.FocusListener;import java.awt.event.KeyEvent;import java.awt.event.KeyListener;import java.awt.event.MouseEvent;import java.awt.event.MouseListener;import java.awt.event.MouseMotionListener;import java.util.HashMap;import javax.swing.JApplet;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JTextField;public class Main extends JApplet { private HashMap hashmap = new HashMap(); private String[] eventlist = {"focusGained", "focusLost", "keyPressed", "keyReleased", "keyTyped", "mouseClicked", "mouseEntered", "mouseExited", "mousePressed", "mouseReleased", "mouseDragged", "mouseMoved"}; private MyButton button1 = new MyButton(Color.cyan, "Button 1"); private MyButton button2 = new MyButton(Color.ORANGE, "Button 2"); public static void main(String[] args) { run(new Main(), 800, 600); } public static void run(JApplet applet, int width, int height) { JFrame jFrame = new JFrame(); jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); jFrame.getContentPane().add(applet); jFrame.setSize(width, height); applet.init(); applet.start(); jFrame.setVisible(true); } class MyButton extends JButton { void report(String str, String output) {((JTextField) hashmap.get(str)).setText(output); } FocusListener focusListener = new FocusListener() {@Overridepublic void focusGained(FocusEvent event) { report("focusGained", event.paramString());}@Overridepublic void focusLost(FocusEvent event) { report("focusLost", event.paramString());} }; KeyListener keyListener = new KeyListener() {@Overridepublic void keyPressed(KeyEvent event) { report("keyPressed", event.paramString());}@Overridepublic void keyReleased(KeyEvent event) { report("keyReleased", event.paramString());}@Overridepublic void keyTyped(KeyEvent event) { report("keyTyped", event.paramString());} }; MouseListener mouseListener = new MouseListener() {@Overridepublic void mouseClicked(MouseEvent event) { report("mouseClicked", event.paramString());}@Overridepublic void mouseEntered(MouseEvent event) { report("mouseEntered", event.paramString());}@Overridepublic void mouseExited(MouseEvent event ){ report("mouseExited", event.paramString());}@Overridepublic void mousePressed(MouseEvent event ){ report("mousePressed", event.paramString());}@Overridepublic void mouseReleased(MouseEvent event) { report("mouseReleased", event.paramString());} }; MouseMotionListener mouseMotionListener = new MouseMotionListener() {@Overridepublic void mouseDragged(MouseEvent event) { report("mouseDragged", event.paramString());}@Overridepublic void mouseMoved(MouseEvent event) { report("mouseMoved", event.paramString());} }; public MyButton(Color color, String label) {super(label);setBackground(color);addFocusListener(focusListener);addKeyListener(keyListener);addMouseListener(mouseListener);addMouseMotionListener(mouseMotionListener); } } @Override public void init() { Container container = getContentPane(); container.setLayout(new GridLayout(eventlist.length + 1, 2)); for (int c = 0; c < eventlist.length; c++) {JTextField jTextField = new JTextField();jTextField.setEditable(false);container.add(new JLabel(eventlist, JLabel.RIGHT)); container.add(jTextField); hashmap.put(eventlist, jTextField); } container.add(button1); container.add(button2); } } |
This was an example on how to display all the occurring events in a Java Desktop application.
