第一个GUI~
package GUI;import javax.swing.*;public class SimpleGui1 {public static void main(String[] args) {JFrame frame = new JFrame();JButton button = new JButton("Click me");//这一行程序会在window关闭时把程序结束掉frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//把Button加到frame的pane上frame.getContentPane().add(button);//设定frame的大小frame.setSize(300, 300);//最后把frame显示出来frame.setVisible(true);}}
下一步应该给按钮添加功能
1.按钮被按下时要执行的方法
2.检测按钮被按下的方法
如果想要知道按钮的事件，就会监听事件的接口
监听接口是介于监听（你）与事件源（按钮）间的桥梁
取得按钮的ActionEvent
1.实现ActionListener这个接口
2.向按钮注册（告诉他你要监听的事件）
3.定义事件处理的方法（实现接口上的方法）
//按下按钮圆圈就会改变颜色package GUI;import javax.swing.*;import java.awt.*;import java.awt.event.*;public class SimpleGui3C implements ActionListener{JFrame frame;public static void main(String[] args){SimpleGui3C gui = new SimpleGui3C();gui.go();}public void go(){frame = new JFrame();frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);JButton button = new JButton("Change colors");//向按钮注册button.addActionListener(this);MyDrawPanel drawPanel = new MyDrawPanel();frame.getContentPane().add(BorderLayout.SOUTH,button);frame.getContentPane().add(BorderLayout.CENTER, drawPanel);frame.setSize(300, 300);frame.setVisible(true);}//实现Interface上的方法public void actionPerformed(ActionEvent event) {frame.repaint();}}class MyDrawPanel extends JPanel {public void paintComponent(Graphics g) {Graphics2D g2d = (Graphics2D) g;int red = (int)(Math.random()*255);int green = (int)(Math.random()*255);int blue = (int)(Math.random()*255);Color startColor = new Color(red, green, blue);red = (int)(Math.random()*255);green = (int)(Math.random()*255);blue = (int)(Math.random()*255);Color endColor = new Color(red, green, blue);GradientPaint gradient = new GradientPaint(70, 70, startColor, 150, 150, endColor);g2d.setPaint(gradient);g2d.fillOval(70, 70, 100, 100);}}
程序料理 制作音乐录像带，使用Java随机产生的圆形来跟着寄走跳舞
这个非GUI的事件会向事件源注册而由音乐本身来出发。
这个程序需要以下几个功能：
1.制作一系列的MIDI信息/事件来播放任意的钢琴音
1.制作一系列的MIDI信息/事件来播放任意的钢琴音
2.对事件注册一个监听者
3.开始sequecer的播放操作
4.每当监听者的事件处理程序调用时，在面板画面上画一个随机的方块并调用repaint
制作程序的三个阶段阶段：
第一版：简单的制作出MIDI事件
第二版：注册并监听事件，但没有图形。从命令行中每一排对应输出一个数据
第三版：最终版本，第二版基础上加上图形输出
第一版：
package MiniMusicPlayer;import javax.sound.midi.*;public class MiniMusicPlayer1 {public static void main(String[] args) {try {// 创建并打开队列Sequencer sequencer = MidiSystem.getSequencer();sequencer.open();// 创建队列并trackSequence seq = new Sequence(Sequence.PPQ, 4);Track track = seq.createTrack();// 创建一堆连续的音符事件for(int i = 5; i < 61; i+= 4) {// 调用makeEvent()来产生信息和时间然后把他们加到track上track.add(makeEvent(144,1,i,100, i));track.add(makeEvent(128,1,i,100,i+2));}//结束循环// 开始播放sequencer.setSequence(seq);sequencer.setTempoInBPM(220);sequencer.start();} catch (Exception ex) {ex.printStackTrace();}}public static MidiEvent makeEvent(int comd, int chan, int one, int two, int tick) {MidiEvent event = null;try {ShortMessage a = new ShortMessage();a.setMessage(comd, chan, one, two);event = new MidiEvent(a, tick);} catch (Exception e) {}return event;}}
第二版
package MiniMusicPlayer;import javax.sound.midi.*;//我们必须要监听ControllerEvent，因此实现了这个接口public class MiniMusicPlayer2 implements ControllerEventListener{public static void main (String[] args) {MiniMusicPlayer2 mini = new MiniMusicPlayer2();mini.go();}public void go(){try{Sequencer sequencer =MidiSystem.getSequencer();sequencer.open();// 向sequencer注册事件。注册的方法取用监听者与代表想要临听的事件的Int数组，我们只需要127事件int[] eventsIWant = {127};sequencer.addControllerEventListener(this, eventsIWant);Sequence seq = new Sequence(Sequence.PPQ, 4);Track track = seq.createTrack();for (int i= 5; i<60; i+=4) {track.add(makeEvent(144,1,i,100,i));// 插入事件为127的自定义ControllEvent(176)它不会做任何事件，只是让我们知道有音符在播放，因为它的Tick跟NOTE ON// 是同时进行的track.add(makeEvent(176,1,127,0,i));track.add(makeEvent(128,1,i,100,i+2));}//结束循环sequencer.setSequence(seq);sequencer.setTempoInBPM(220);sequencer.start();} catch (Exception e) { e.printStackTrace();}}// 获知事件时在命令打印出字符串的事件处理程序public void controlChange(ShortMessage event) {System.out.println("la");}public MidiEvent makeEvent(int comd, int chan, int one, int two, int tick) {MidiEvent event = null;try{ShortMessage a = new ShortMessage();a.setMessage(comd, chan, one, two);event = new MidiEvent(a, tick);} catch(Exception e) {};return event;}}
第三版
package MiniMusicPlayer;import javax.sound.midi.*;import javax.swing.*;import java.awt.*;public class MiniMusicPlayer3 {static JFrame f = new JFrame("My First Music Video");static MyDrawPanel ml;public static void main (String[] args) {MiniMusicPlayer3 mini = new MiniMusicPlayer3();mini.go();}public void setUpGui() {ml = new MyDrawPanel();f.setContentPane(ml);f.setBounds(30,30,300,300);f.setVisible(true);}public void go(){setUpGui();try{Sequencer sequencer =MidiSystem.getSequencer();sequencer.open();// 向sequencer注册事件。注册的方法取用监听者与代表想要临听的事件的int数组，我们只需要127事件sequencer.addControllerEventListener(ml, new int[] {127});Sequence seq = new Sequence(Sequence.PPQ, 4);Track track = seq.createTrack();int r = 0;for (int i= 5; i<60; i+=4) {r= (int)((Math.random()*50));track.add(makeEvent(144,1,r,100,i));// 插入事件为127的自定义ControllEvent(176)它不会做任何事件，只是让我们知道有音符在播放，因为它的Tick跟NOTE ON// 是同时进行的track.add(makeEvent(176,1,127,0,i));track.add(makeEvent(128,1,r,100,i+2));}//结束循环sequencer.setSequence(seq);sequencer.setTempoInBPM(220);sequencer.start();} catch (Exception e) { e.printStackTrace();}}public MidiEvent makeEvent(int comd, int chan, int one, int two, int tick) {MidiEvent event = null;try{ShortMessage a = new ShortMessage();a.setMessage(comd, chan, one, two);event = new MidiEvent(a, tick);} catch(Exception e) {};return event;}class MyDrawPanel extends JPanel implements ControllerEventListener {/****/private static final long serialVersionUID = 1L;boolean msg = false;public void controlChange(ShortMessage event) {msg = true ;repaint();}public void paintComponent(Graphics g) {if (msg) {Graphics2D g2 = (Graphics2D) g;int r = (int)(Math.random()*250);int gr = (int)(Math.random()*250);int b = (int) (Math.random()*250);g2.setColor(new Color(r,gr,b));int ht =(int) ((Math.random()*120)+10);int width = (int)((Math.random()*120)+10);int x = (int)((Math.random()*40)+10);int y = (int)((Math.random()*40)+10);g2.fillRect(x, y, ht, width);msg = false;}}}}最终效果图：
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