android多线程：自己撰写Proxy/Stub播放MP3音乐

一、架构设计

在这个范例中，定义了一个IPlayer接口，然后规划了PlayerProxy和PlayerStub两个类，如下图：



于是，PlayerProxy与PlayerStub分别位于跨进程IPC的两端。

二、完整的实现程序

AndroidManifest.xml：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.misoo.pxgx"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />

<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.misoo.pxgx.ac01"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>

<service
android:name=".Mp3RemoteService"
android:process=".remote" >
<intent-filter>
<action android:name="com.misoo.pkgx.REMOTE_SERVICE" />
</intent-filter>
</service>
</application>

</manifest>

IPlayer：

package com.misoo.pxgx;

public interface IPlayer {
void play();
void stop();
String getStatus();
}

Mp3RemoteService ：

package com.misoo.pxgx;

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;

public class Mp3RemoteService extends Service {
private IBinder mBinder = null;

public void onCreate() {
mBinder = new Mp3Binder(getApplicationContext());
}

public IBinder onBind(Intent intent) {
return mBinder;
}
}

PlayerStub：

package com.misoo.pxgx;

import android.os.Binder;
import android.os.Parcel;
import android.os.RemoteException;

public abstract class PlayerStub extends Binder implements IPlayer {
protected boolean onTransact(int code, Parcel data, Parcel reply, int flags)
throws RemoteException {
reply.writeString(data.readString() + " mp3");
if(code == 1) this.play();
else if(code == 2) this.stop();
return true;
}

public abstract void play();

public abstract void stop();

public abstract String getStatus();

}

Mp3Binder：

package com.misoo.pxgx;

import android.content.Context;
import android.media.MediaPlayer;
import android.util.Log;

public class Mp3Binder extends PlayerStub {
private MediaPlayer mediaPlayer = null;
private Context ctx;

public Mp3Binder(Context cx) {
ctx = cx;
}

public void play() {
if(mediaPlayer  != null) return;
mediaPlayer = MediaPlayer.create(ctx, R.raw.san);
try {
mediaPlayer.start();
} catch (IllegalStateException e) {
Log.e("StartPlay", "error:" + e.getMessage(), e);
}
}

public void stop() {
if(mediaPlayer != null){
mediaPlayer.stop();
mediaPlayer.release();
mediaPlayer = null;
}
}

public String getStatus() {
return null;
}

}

ac01：

package com.misoo.pxgx;

import android.os.Bundle;
import android.os.IBinder;
import android.os.Parcel;
import android.os.RemoteException;
import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;

public class ac01 extends Activity implements OnClickListener{
private final int WC = LinearLayout.LayoutParams.WRAP_CONTENT;
private final int MP = LinearLayout.LayoutParams.MATCH_PARENT;
private Button btn0, btn1, btn2;
public TextView tv;
private PlayerProxy playerProxy = null;

protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
LinearLayout layout = new LinearLayout(this);
layout.setOrientation(LinearLayout.VERTICAL);

btn0 = new Button(this);
btn0.setId(101); btn0.setText("play");
btn0.setOnClickListener(this);

btn1 = new Button(this);
btn1.setId(102); btn1.setText("stop");
btn1.setOnClickListener(this);

btn2 = new Button(this);
btn2.setId(103); btn2.setText("exit");
btn2.setOnClickListener(this);

LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(135, 60);
params.topMargin = 10;
layout.addView(btn0, params);
layout.addView(btn1, params);
layout.addView(btn2, params);

tv = new TextView(this);
tv.setText("Ready");
LinearLayout.LayoutParams params2 = new
LinearLayout.LayoutParams(MP,  WC);
params2.topMargin = 10;
layout.addView(tv, params2);

setContentView(layout);
startService(new Intent("com.misoo.pkgx.REMOTE_SERVICE"));
bindService(new Intent("com.misoo.pkgx.REMOTE_SERVICE"),
mConnection, Context.BIND_AUTO_CREATE);
}

private ServiceConnection mConnection = new ServiceConnection() {
public void onServiceDisconnected(ComponentName name) {

}

public void onServiceConnected(ComponentName name, IBinder service) {
playerProxy = new PlayerProxy(service);
}
};

public void onClick(View v) {
switch(v.getId()){
case 101:
playerProxy.play();
tv.setText(playerProxy.getStatus());
break;
case 102:
playerProxy.stop();
tv.setText(playerProxy.getStatus());
break;
case 103:
unbindService(mConnection);
stopService(new Intent("com.misoo.pxgx.REMOTE_SERVICE"));
finish();
break;
}
}

private class PlayerProxy implements IPlayer{
private IBinder ib;
private String mStatus;

public PlayerProxy(IBinder ib) {
super();
this.ib = ib;
}

public void play() {
Parcel data = Parcel.obtain();
Parcel reply = Parcel.obtain();
data.writeString("playing");

try {
ib.transact(1, data, reply, 0);
mStatus = reply.readString();
} catch (RemoteException e) {
e.printStackTrace();
}
}

public void stop() {
Parcel data = Parcel.obtain();
Parcel reply = Parcel.obtain();
data.writeString("stop");

try {
ib.transact(2, data, reply, 0);
mStatus = reply.readString();
} catch (RemoteException e) {
e.printStackTrace();
}
}

public String getStatus() {
return mStatus;
}
}
}