android中的多媒體應用MediaPlayer

MediaPlayer可以播放音頻和視頻，另外也可以通過VideoView來播放視頻，雖然VideoView比MediaPlayer簡單易用，但定制性不如用MediaPlayer，要視情況選擇了。MediaPlayer播放音頻比較簡單，但是要播放視頻就需要SurfaceView。SurfaceView比普通的自定義View更有繪圖上的優勢，它支持完全的OpenGL ES庫。

迷你音樂播放器

/Chapter11_Media_MiniPlayer/src/com/amaker/test/MainActivity.java

package com.amaker.test;

import android.app.Activity;
import android.app.AlertDialog;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageButton;

public class MainActivity extends Activity implements MediaPlayer.OnCompletionListener {
    
    private ImageButton play,pause,stop;
    private MediaPlayer mp;
    
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        play = (ImageButton)findViewById(R.id.play);
        pause = (ImageButton)findViewById(R.id.pause);
        stop = (ImageButton)findViewById(R.id.stop);
        
        play.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                play();
            }
        });
        
        pause.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                pause();
            }
        });
        
        stop.setOnClickListener(new View.OnClickListener() {
            public void onClick(View view) {
                stop();
            }
        });
        
        setup();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        if (stop.isEnabled()) {
            stop();
        }
    }
    
    public void onCompletion(MediaPlayer mp) {
        stop();
    }
    
    private void play() {
        mp.start();
        
        play.setEnabled(false);
        pause.setEnabled(true);
        stop.setEnabled(true);
    }
    
    private void stop() {
        mp.stop();
        pause.setEnabled(false);
        stop.setEnabled(false);
        
        try {
            mp.prepare();
            mp.seekTo(0);
            play.setEnabled(true);
        }
        catch (Throwable t) {
            error(t);
        }
    }
    
    private void pause() {
        mp.pause();
        play.setEnabled(true);
        pause.setEnabled(false);
        stop.setEnabled(true);
    }
    
    private void loadClip() {
        try {
            mp=MediaPlayer.create(this, R.raw.test);
            mp.setOnCompletionListener(this);
        }
        catch (Throwable t) {
            error(t);
        }
    }
    
    private void setup() {
        loadClip();
        play.setEnabled(true);
        pause.setEnabled(false);
        stop.setEnabled(false);
    }
    
    private void error(Throwable t) {
        AlertDialog.Builder builder=new AlertDialog.Builder(this);
        builder
            .setTitle("報錯啦!")
            .setMessage(t.toString())
            .setPositiveButton("確定", null)
            .show();
    }
}

/Chapter11_Media_MiniPlayer/res/layout/main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    
    <TextView 
    android:layout_width="fill_parent"
    android:layout_height="wrap_content" 
    android:text="迷你音樂播放器" />
    
    <LinearLayout 
    android:orientation="horizontal" android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    
    <ImageButton 
    android:id="@+id/play"
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content"
    android:src="@drawable/play"
    />
    
    <ImageButton 
    android:id="@+id/pause"
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content"
    android:src="@drawable/pause"
    />
    
    <ImageButton 
    android:id="@+id/stop"
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content"
    android:src="@drawable/stop"
    />
    </LinearLayout>
</LinearLayout>

/Chapter11_Media_MiniPlayer/AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.amaker.test"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".MainActivity"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    </application>
    <uses-sdk android:minSdkVersion="3" />

</manifest>