Android简易实战教程--第三十五话《音乐播放》

已经好几天不更新博客了，今天轻松一点模拟个简单的“音乐播放器”。1分钟看完~

整个简单布局，加几个控制按钮：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <Button
        android:id="@+id/play"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="Play" />

    <Button
        android:id="@+id/pause"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="Pause" />

    <Button
        android:id="@+id/stop"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="Stop" />

</LinearLayout>

主活动代码也是soeasy：

package com.example.playaudiotest;

import java.io.File;

import android.app.Activity;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity implements OnClickListener {

	private Button play;

	private Button pause;

	private Button stop;

	private MediaPlayer mediaPlayer = new MediaPlayer();

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		play = (Button) findViewById(R.id.play);
		pause = (Button) findViewById(R.id.pause);
		stop = (Button) findViewById(R.id.stop);
		play.setOnClickListener(this);
		pause.setOnClickListener(this);
		stop.setOnClickListener(this);
		initMediaPlayer();
	}

	private void initMediaPlayer() {
		try {
			File file = new File(Environment.getExternalStorageDirectory(), "music.mp3");
			//设置播放路径，资源
			mediaPlayer.setDataSource(file.getPath());
			//播放前的准备工作
			mediaPlayer.prepare();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	@Override
	public void onClick(View v) {
		switch (v.getId()) {
		case R.id.play:
			if (!mediaPlayer.isPlaying()) {
				//开始播放
				mediaPlayer.start();
			}
			break;
		case R.id.pause:
			if (mediaPlayer.isPlaying()) {
				//暂停播放
				mediaPlayer.pause();
			}
			break;
		case R.id.stop:
			if (mediaPlayer.isPlaying()) {
				//Resets the MediaPlayer to its uninitialized state. After calling this method, you will have to initialize it again by setting the data source and calling prepare(). 
				//重置，如果调用此方法，必须人为的再次调用设置资源、准备方法
				mediaPlayer.reset();
				initMediaPlayer();
			}
			break;
		default:
			break;
		}
	}

	@Override
	protected void onDestroy() {
		super.onDestroy();
		if (mediaPlayer != null) {
			mediaPlayer.stop();
			mediaPlayer.release();
		}
	}

}

需要重点关注的是mediaPlayer.reset();方法。看文档说明：

Resets the MediaPlayer to its uninitialized state. After calling this method, you will have to initialize it again by setting the data source and calling prepare().
大致意思是：重置，如果调用此方法，必须人为的再次调用设置资源、准备方法

既然调用了就在此调用initMediaPlayer();

运行，开始听音乐吧~~

对于MediaPlayer这个类的一些认识，可以参考Android初级教程的一篇博客：MediaPlayer的生命周期