Android进程通信：AIDL入门实例

AIDL即 Android Interface Definition Language。原因：On Android, one process cannot normally access thememory of another process.

也就是说AIDL用于android进程间通信，下面就记录一下第一个aidl的demo。

官方文档也给出了基本的使用方法，如下图：

1. 在android项目的src相关包下创建一个aidl文件 IRemoteService.aidl：

package com.example.testndk;interface IRemoteService {    /** Request the process ID of this service, to do evil things with it. */    int getPid();    /** Demonstrates some basic types that you can use as parameters     * and return values in AIDL.     */    void basicTypes(int anInt, long aLong, boolean aBoolean, float aFloat,            double aDouble, String aString);}

创建成功后会在gen目录自动生成一个同名的java文件，打开可以看到其实是一个接口

public interface IRemoteService extends android.os.IInterface

2. 实现这个接口

package com.example.testndk;import android.app.Service;import android.content.Intent;import android.os.IBinder;import android.os.Process;public class RemoteService extends Service {    @Override    public void onCreate() {        super.onCreate();    }    @Override    public IBinder onBind(Intent intent) {        // Return the interface        return mBinder;    }    private final IRemoteService.Stub mBinder = new IRemoteService.Stub() {        public int getPid(){            return Process.myPid();        }        public void basicTypes(int anInt, long aLong, boolean aBoolean,            float aFloat, double aDouble, String aString) {            // Does nothing        }    };}

3. 把接口暴露给客户端，即调用处

package com.example.testndk;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 android.widget.TextView;public class TestNdkActivity extends Activity {    private static final String TAG = "TestNdkActivity";    private TextView tv1 = null;    // static {    // System.loadLibrary("TestNdk");    // }    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        //        // String str = JniClient.AddStr("prefix", "suffix");        //        //        // int iSum = JniClient.AddInt(5, 2);        // String strSum = "5 + 2 = " + iSum;        tv1 = new TextView(this);        bindService(new Intent(RemoteService.class.getName()), mConnection, Context.BIND_AUTO_CREATE);        setContentView(tv1);    }    IRemoteService mIRemoteService = null;    private ServiceConnection mConnection = new ServiceConnection() {        // Called when the connection with the service is established        public void onServiceConnected(ComponentName className, IBinder service) {            // Following the example above for an AIDL interface,            // this gets an instance of the IRemoteInterface, which we can use            // to call on the service            mIRemoteService = IRemoteService.Stub.asInterface(service);            try {                tv1.setText("mIRemoteService=" + mIRemoteService.getPid());            } catch (RemoteException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }        // Called when the connection with the service disconnects unexpectedly        public void onServiceDisconnected(ComponentName className) {            Log.e(TAG, "Service has unexpectedly disconnected");            mIRemoteService = null;        }    };    protected void onDestroy() {        super.onDestroy();        unbindService(mConnection);    }}

用到了service，还需在AndroidManifest.xml配置一下，添加

        <service android:name="com.example.testndk.RemoteService">            <intent-filter>                <action android:name="com.example.testndk.RemoteService"/>            </intent-filter>        </service>

因为是通过action来查找service的，所以action标签不可少。

官方文档的例子稍微麻烦一点，不过也是比较清楚的。