如何在Android上發展IPC應用程式

Google Android制訂一套新的語言，稱為AIDL (Android Interface Definition Language)來協助程式設計師發展IPC(InterProcess Communication)應用程式。AIDL是以介面為基礎，類似於COM或Corba但較為輕量，它使用代理類別(Proxy Class)在兩程序(客戶端及實作端)傳遞數值。
本文將介紹如何快速建立AIDL應用程式的步驟：

1. 實作Activity

package com.example.RemoteServiceController;

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

public class RemoteServiceController extends Activity {
 private IRemoteService iservice=null;
 TextView tv;
 private ServiceConnection connection= new ServiceConnection(){

  @Override
  public void onServiceConnected(ComponentName name, IBinder service) {
   iservice =  IRemoteService.Stub.asInterface(service);
   setTitle("Connect");
   int i = 0;
   try {
    i= iservice.sum(4, 5);
    
   } catch (RemoteException e) {
    e.printStackTrace();
   }
   tv.setText(Integer.toString(i));
  }

  @Override
  public void onServiceDisconnected(ComponentName name) {
   iservice = null;  }
  
 };    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        tv=(TextView) findViewById(R.id.Text01);
        Button start = (Button) findViewById(R.id.start);
        start.setOnClickListener(new OnClickListener(){
   @Override
   public void onClick(View v) {
    // TODO Auto-generated method stub
    bindService(new Intent(RemoteServiceController.this, RemoteService.class), connection, Context.BIND_AUTO_CREATE);
   }
         
        });
        Button stop =(Button) findViewById(R.id.stop);
        stop.setOnClickListener(new OnClickListener(){

   @Override
   public void onClick(View v) {
    // TODO Auto-generated method stub
    unbindService(connection);
    setTitle("Disonnect");   }
         
        });
    }}

2. 建立AIDL介面

package com.example.RemoteServiceController;

interface IRemoteService {
   int sum(int a, int b);
}

3. 建立服務程式

package com.example.RemoteServiceController;

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

public class RemoteService extends Service {
 private final IRemoteService.Stub binder= new IRemoteService.Stub(){

  @Override
  public int sum(int a, int b) throws RemoteException {
   return a+b;
  }
  
 };
 @Override
 public IBinder onBind(Intent arg0) {
  // TODO Auto-generated method stub
  return this.binder; }
}

4. 修改AndroidManifest.xml
<service android:name="RemoteService" android:process=":remote">
</service>