通过aidl service调用activity

使用android中的AIDL让Service与Activity通信


这几天搞了搞AIDL,终于弄明白了在AIDL中让Service调用Activity的方法
代码:
首先建立一个ICallback.aidl文件,作为Activity中的回调方法
view plaincopy to clipboardprint?
package com.zhang.test.service; 
 
interface ICallback { 
void showResult(int result); 
} 

然后再建立一个IService.aidl用来在Activity中接收Service回调,以及在Service中onBind时返回的Binder
注意:aidl中import不能写com.xxx.*,要写全类的路径
view plaincopy to clipboardprint?
package com.zhang.test.service; 
 
import com.zhang.test.service.ICallback; 
 
interface IService { 
    void registerCallback(ICallback cb); 
    void unregisterCallback(ICallback cb); 
} 

接下来是service:
MainService.java
view plaincopy to clipboardprint?
package com.zhang.test.service; 
 
import android.app.Service; 
import android.content.Intent; 
import android.os.Handler; 
import android.os.IBinder; 
import android.os.Message; 
import android.os.RemoteCallbackList; 
import android.os.RemoteException; 
import android.util.Log; 
 
public class MainService extends Service { 
 
    private static final String TAG = "MainService"; 
 
    private RemoteCallbackList<icallback> mCallbacks = new RemoteCallbackList<icallback>(); 
 
    private IService.Stub mBinder = new IService.Stub() { 
 
        @Override 
        public void unregisterCallback(ICallback cb){ 
            if(cb != null) { 
                mCallbacks.unregister(cb); 
            } 
        } 
 
        @Override 
        public void registerCallback(ICallback cb){ 
            if(cb != null) { 
                mCallbacks.register(cb); 
            } 
        } 
    }; 
 
    @Override 
    public IBinder onBind(Intent intent) { 
        Log.d(TAG, "onBind"); 
        return mBinder; 
    } 
 
    @Override 
    public void onCreate() { 
        Log.d(TAG, "onCreate"); 
        //这里不知道为什么,直接使用callback方法回调showResult 
        //mCallbacks.beginBroadcast()是0,需要用handler延迟1000毫秒 
        //也许是在activity中binService太耗时的原因? 
        mHandler.sendEmptyMessageDelayed(0, 1000); 
        super.onCreate(); 
    } 
 
    @Override 
    public void onDestroy() { 
        mHandler.removeMessages(0); 
        mCallbacks.kill(); 
        super.onDestroy(); 
    } 
 
    private void callBack() { 
        int N = mCallbacks.beginBroadcast(); 
        try { 
            for (int i = 0; i < N; i++) { 
                mCallbacks.getBroadcastItem(i).showResult(i); 
            } 
        } catch (RemoteException e) { 
            Log.e(TAG, "", e); 
        } 
        mCallbacks.finishBroadcast(); 
    } 
 
    private Handler mHandler = new Handler() { 
 
        @Override 
        public void handleMessage(Message msg) { 
            callBack(); 
            super.handleMessage(msg); 
        } 
    }; 
} 

然后是activity:
view plaincopy to clipboardprint?
package com.zhang.test; 
 
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.util.Log; 
 
import com.zhang.test.service.ICallback; 
import com.zhang.test.service.IService; 
import com.zhang.test.service.MainService; 
 
public class MainActivity extends Activity { 
 
    private static final String TAG = "MainActivity"; 
 
    private IService mService; 
 
    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.main); 
        Intent i = new Intent(this, MainService.class); 
        bindService(i, mConnection, Context.BIND_AUTO_CREATE); 
    } 
 
    @Override 
    protected void onDestroy() { 
        if(mService!=null){ 
            try { 
                mService.unregisterCallback(mCallback); 
            } catch (RemoteException e) { 
                Log.e(TAG, "", e); 
            } 
        } 
        //destroy的时候不要忘记unbindService 
        unbindService(mConnection); 
        super.onDestroy(); 
    } 
 
    /**
     * service的回调方法
     */ 
    private ICallback.Stub mCallback = new ICallback.Stub() { 
 
        @Override 
        public void showResult(int result) { 
            Log.d(TAG, " result : " + result); 
        } 
    }; 
 
    /**
     * 注册connection
     */ 
    private ServiceConnection mConnection = new ServiceConnection() { 
 
        @Override 
        public void onServiceDisconnected(ComponentName name) { 
            Log.d(TAG, "onServiceDisconnected"); 
            mService = null; 
        } 
 
        @Override 
        public void onServiceConnected(ComponentName name, IBinder service) { 
            Log.d(TAG, "onServiceConnected"); 
            mService = IService.Stub.asInterface(service); 
            try { 
                mService.registerCallback(mCallback); 
            } catch (RemoteException e) { 
                Log.e(TAG, "", e); 
            } 
        } 
    }; 
} 

最后不要忘记在manifest中加上service标记:
view plaincopy to clipboardprint?
<service android:name=".service.MainService"> 

运行程序,查看Logcat
结果如下:

总结:
通过aidl总算实现了Service与Activity的通信,写起来麻烦点,使用诸如ContentProvider,Broadcast等也可以实现.
这样做很像是在使用MVC设计模式(Activity负责View,Service以及其他类负责Model,aidl(ServiceConnection)负责Controller),其实我对于aidl也是一知半解- -,明天研究下如何让activity去调用service中的方法.

评论

1 楼 rsic 2011-03-06  

谢谢分享，很受启发