安卓 音樂播放 學習筆記

主文件

package com.tang.play;

import java.io.File;
import java.io.IOException;

import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.drm.DrmStore.Playback;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.media.MediaPlayer.OnErrorListener;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import android.os.Build;

public class MainActivity extends Activity implements OnClickListener {
	private EditText et;
	private Button bt1;
	private Button bt2;
	private Button bt3;
	private Button bt4;
	private MediaPlayer mp;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		et = (EditText) findViewById(R.id.et);
		bt1 = (Button) findViewById(R.id.bt1);
		bt2 = (Button) findViewById(R.id.bt2);
		bt3 = (Button) findViewById(R.id.bt3);
		bt4 = (Button) findViewById(R.id.bt4);
		bt1.setOnClickListener(this);
		bt2.setOnClickListener(this);
		bt3.setOnClickListener(this);
		bt4.setOnClickListener(this);		
	}
	public void onClick(View v) {
		switch (v.getId()) {
		case R.id.bt1:
			play();
			break;

		case R.id.bt2:
			pause();
			break;

		case R.id.bt3:
			rePlay();
			break;
			
		case R.id.bt4:
			stop();
			break;			
		}
		
	}
	/**
	 * 中止
	 */
	private void stop() {
		if (mp != null && mp.isPlaying()) {
			mp.start();
			mp.release();
			mp = null;
			bt1.setEnabled(true);
			return ;
		}
	}
	/**
	 * 重複播放
	 */
	private void rePlay() {
		if (mp != null && mp.isPlaying()) {
			mp.seekTo(0);
			return ;
		}
		play();
	}
	/**
	 * 暫停
	 */
	private void pause() {
		if ("繼續".equals(bt2.getText().toString().trim())) {
			bt2.setText("暫停");
			mp.start();
			return;
		}
		if (mp != null && mp.isPlaying()) {
			mp.pause();
			bt2.setText("繼續");
		}
	}
	/**
	 * 播放
	 */
	private void play() {
		String path = et.getText().toString().trim();
		File file = new File(path);
		if (file.exists() && file.length()>0) {
			mp = new MediaPlayer();
			mp.setAudioStreamType(AudioManager.STREAM_MUSIC);
			try {
				mp.setDataSource(path);
				mp.prepare();
				mp.start();
				mp.setOnCompletionListener(new OnCompletionListener() {
					//播放完成的回調
					public void onCompletion(MediaPlayer mediaPlay) {
						bt1.setEnabled(true);
					}
				});
				mp.setOnErrorListener(new OnErrorListener() {
					
					@Override
					public boolean onError(MediaPlayer arg0, int arg1, int arg2) {
						bt1.setEnabled(true);
						return false;
					}
				});
				bt1.setEnabled(false);
			} catch (Exception e) {
				Toast.makeText(this, "播放失敗", Toast.LENGTH_SHORT).show();
				e.printStackTrace();
			}

		} else {
			Toast.makeText(this, "文件不存在", Toast.LENGTH_SHORT).show();
		}
	}
}

##佈局文件

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

    <EditText
        android:hint="請輸入mp3地址"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/et" />
    <LinearLayout
    	android:orientation="horizontal"
    	android:layout_width="match_parent"
    	android:layout_height="match_parent" >
    	<Button 
    	    android:layout_weight="1"
    	    android:layout_height="wrap_content"
    	    android:layout_width="0dip"
    	    android:id="@+id/bt1"
    	    android:text="播放"
    	    />
    	<Button 
    	    android:layout_weight="1"
    	    android:layout_height="wrap_content"
    	    android:layout_width="0dip"
    	    android:id="@+id/bt2"
    	    android:text="暫停"
    	    />
    	<Button 
    	    android:layout_weight="1"
    	    android:layout_height="wrap_content"
    	    android:layout_width="0dip"
    	    android:id="@+id/bt3"
    	    android:text="重播"
    	    />
    	<Button 
    	    android:layout_weight="1"
    	    android:layout_height="wrap_content"
    	    android:layout_width="0dip"
    	    android:id="@+id/bt4"
    	    android:text="中止"
    	    />    	    	    	
	</LinearLayout>
</LinearLayout>

清單文件 權限的設置

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>