musiccanvas.java

J2ME中音量的控制

import java.io.IOException;
import java.io.InputStream;

import javax.microedition.lcdui.*;
import javax.microedition.media.*;
import javax.microedition.media.control.*;

public class MusicCanvas extends Canvas implements Runnable {

	private boolean running = false; // 线程是否在运行

	private Player player = null; // Player

	static final int VOLUME_LEVEL = 50; // 音量初始化为50

	private int volumesetting = VOLUME_LEVEL; // 音量级别

	private boolean volumemuted = false; //是否暂停播放了	

	protected void paint(Graphics g) {	

	}

	public void start() {
		running = true;
		Thread t = new Thread(this);
		t.start();
	}

	public void run() {
		while (running) {
			repaint();
			try {
				Thread.sleep(100);
			} catch (InterruptedException ie) {
				System.out.println("Thread exception");
			}
		}
	}

	public void stop() {
		running = false;
		if (player != null) {
			player.close();
			player = null;
		}
	}

	public void playsong() {		
		
		try {
			//	创建player对象
			if (player == null){
				InputStream in = getClass().getResourceAsStream("/test-wav.wav");
				//指定文件类型
				 player = Manager.createPlayer(in, "audio/x-wav");
			}
				
			player.realize();
			//	设置循环播放次数
			player.setLoopCount(1);
			//	 设置音量为50
			VolumeControl volume = (VolumeControl) player
					.getControl("VolumeControl");
			volume.setLevel(VOLUME_LEVEL);
			
			player.start();
		} catch (IOException ioe) {
			System.out.println("IO Exception!");
		} catch (MediaException me) {
			System.out.println("Media Exception!");
		}
	} 

	protected void keyPressed(int keycode) {
		switch (getGameAction(keycode)) {
		case LEFT:
			adjustvolume(-5, false);
			break;
		case RIGHT:
			adjustvolume(5, false);
			break;
		case FIRE:
			adjustvolume(0, true);
			break;
		}
	}

	private void adjustvolume(int increment, boolean mute) {
		if (player != null) {
			VolumeControl volume = (VolumeControl) player
					.getControl("VolumeControl");
			if (volume != null) {
				//	目前音量级别
				volumesetting = volume.getLevel();
				//	如果不是消音了，即停止播放了
				if (mute != true) {
					//	调整音量
					volumesetting += increment;					
					volumesetting = volume.setLevel(volumesetting);
				} else {					
					volume.setMute(!volume.isMuted());
					volumemuted = volume.isMuted();
				}
			}
		}
	}

}