android process communication between two application

实现两个application之间的进程通信，需要用到service，并且在client端根据是否需要多线程可以分成使用Messenger和AIDL两种方法来实现。当你的client端需要多个线程时，此时需要用到AIDL， 在AIDL的方法，当被remote process调用时，会在thread pool启动一个线程来实现。下面是方法步骤：

一. 首先在Android studio中建立自己的AIDL 接口，并提供 相应的方法。如 ，

// IMyAidlInterface.aidl
package com.example.almoliu.aidlserver;

// Declare any non-default types here with import statements

interface IMyAidlInterface {
/**
* 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);

long getCount();
}

然后在server端启动一个service，并实现该接口，返回该接口的一个Stub（IBinder）实例。如,

package com.example.almoliu.aidlserver;

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

import java.lang.ref.WeakReference;

public class CounterService extends Service {

private long counter = 0;
private static int WHOLE_COUNT = 60000;
private static int INTERVAL_COUNT = 1000;

private CountDownTimer mCountDownTimer = new CountDownTimer(WHOLE_COUNT,INTERVAL_COUNT) {
@Override
public void onTick(long millisUntilFinished) {
counter = millisUntilFinished/INTERVAL_COUNT;
}
@Override
public void onFinish() {
counter = -1;
}
};

public CounterService() {
}
@Override
public void onCreate() {
super.onCreate();
Thread thread = new Thread(new Runnable() {
@Override
public void run() {
mCountDownTimer.start();
}
});
thread.start();
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
return super.onStartCommand(intent, flags, startId);
}

@Override
public void onDestroy() {
super.onDestroy();
mCountDownTimer.cancel();
}

private long getCounter() {
return counter;
}

@Override
public IBinder onBind(Intent intent) {
// TODO: Return the communication channel to the service.
return mIBinder;
}

static private class MyStub extends IMyAidlInterface.Stub {

private WeakReference<CounterService> mWeakCounterService;

public MyStub(CounterService counterService) {
mWeakCounterService = new WeakReference<CounterService>(counterService);
}

@Override
public void basicTypes(int anInt, long aLong, boolean aBoolean, float aFloat, double aDouble, String aString) throws RemoteException {

}

@Override
public long getCount() throws RemoteException {
return mWeakCounterService.get().getCounter();
}
}

private IBinder mIBinder = new MyStub(this);

}

然后需要在AndroidManifest文件中定义该服务的ACTION和属性，来提供绑定该service的途径。如

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.almoliu.aidlserver">

<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>

<service
android:name=".CounterService"
android:enabled="true"
android:exported="true"
android:process=":remote">
<intent-filter>
<action android:name="com.example.almoliu.CounterService"></action>
<category android:name="android.intent.category.DEFAULT"></category>
</intent-filter>
</service>
</application>

</manifest>

然后在client端，首先你需要建立一个同样的AIDL文件，且要保证与Server端 的AIDL文件是统一个package，然后定义自己的ServiceConnection，实现AIDL接口的实例，如

package com.example.almoliu.aidlclient;

import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.os.RemoteException;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import com.example.almoliu.aidlserver.IMyAidlInterface;

public class MainActivity extends AppCompatActivity {

TextView tv;
private IMyAidlInterface iMyAidlInterface;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

tv = (TextView)findViewById(R.id.text_tv);

Button mButton = (Button)findViewById(R.id.start_btn);
mButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
try {
long value = iMyAidlInterface.getCount();
tv.append(String.valueOf(value));
} catch (RemoteException e) {
e.printStackTrace();
}

}
});

Intent i = new Intent("com.example.almoliu.CounterService");
bindService(i,mServiceCOnnection,BIND_AUTO_CREATE);
}

@Override
protected void onDestroy() {
super.onDestroy();
unbindService(mServiceCOnnection);
}

private ServiceConnection mServiceCOnnection = new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
iMyAidlInterface = IMyAidlInterface.Stub.asInterface(service);

}

@Override
public void onServiceDisconnected(ComponentName name) {
iMyAidlInterface = null;
}
};

}

这样你就可以通过 private IMyAidlInterface iMyAidlInterface调用server中的service方法了。