android开发步步为营之62:进程间通信之Aidl

           android进程之间通信，比如一个app和另外一个app交互，有哪几种方式，主要有1、activity的跳转  2、contentprovider  3、broadcast  4、aidl，个人认为前面3种相对简单，应用场景也不一样。本文研究一下使用aidl进行进程之间的通信。

           aidl全称是Android Interface Definition Language，即接口定义语言，依我理解，这个其实和.net,java里面的webservice相似的，webservice也有个wsdlWeb Services Description Language，服务端通过定义接口，自动生成代理类。然后客户端使用这个代理类来调用服务端的相应服务。android aidl是通过绑定服务service来实现的。本文写了个demo，之前一直做第三方支付，这里就模拟第三方支付的场景，支付app（服务端）提供一个aidl支付接口给应用app（客户端）来调用完成支付功能。

        第一步：服务端定义支付接口AidlTestInterface.aidl

/** *  */package com.figo.study.aidl;/** * @author figo * */interface AidlTestInterface {    int pay(String orderId,String productName,float money);}

然后看到gen文件夹下面会自动生成stub代理类了。

/* * This file is auto-generated.  DO NOT MODIFY. * Original file: E:\\projects\\Study\\src\\com\\figo\\study\\aidl\\AidlTestInterface.aidl */package com.figo.study.aidl;/** * @author figo * */public interface AidlTestInterface extends android.os.IInterface{/** Local-side IPC implementation stub class. */public static abstract class Stub extends android.os.Binder implements com.figo.study.aidl.AidlTestInterface{private static final java.lang.String DESCRIPTOR = "com.figo.study.aidl.AidlTestInterface";/** Construct the stub at attach it to the interface. */public Stub(){this.attachInterface(this, DESCRIPTOR);}/** * Cast an IBinder object into an com.figo.study.aidl.AidlTestInterface interface, * generating a proxy if needed. */public static com.figo.study.aidl.AidlTestInterface asInterface(android.os.IBinder obj){if ((obj==null)) {return null;}android.os.IInterface iin = obj.queryLocalInterface(DESCRIPTOR);if (((iin!=null)&&(iin instanceof com.figo.study.aidl.AidlTestInterface))) {return ((com.figo.study.aidl.AidlTestInterface)iin);}return new com.figo.study.aidl.AidlTestInterface.Stub.Proxy(obj);}@Override public android.os.IBinder asBinder(){return this;}@Override public boolean onTransact(int code, android.os.Parcel data, android.os.Parcel reply, int flags) throws android.os.RemoteException{switch (code){case INTERFACE_TRANSACTION:{reply.writeString(DESCRIPTOR);return true;}case TRANSACTION_pay:{data.enforceInterface(DESCRIPTOR);java.lang.String _arg0;_arg0 = data.readString();java.lang.String _arg1;_arg1 = data.readString();float _arg2;_arg2 = data.readFloat();int _result = this.pay(_arg0, _arg1, _arg2);reply.writeNoException();reply.writeInt(_result);return true;}}return super.onTransact(code, data, reply, flags);}private static class Proxy implements com.figo.study.aidl.AidlTestInterface{private android.os.IBinder mRemote;Proxy(android.os.IBinder remote){mRemote = remote;}@Override public android.os.IBinder asBinder(){return mRemote;}public java.lang.String getInterfaceDescriptor(){return DESCRIPTOR;}@Override public int pay(java.lang.String orderId, java.lang.String productName, float money) throws android.os.RemoteException{android.os.Parcel _data = android.os.Parcel.obtain();android.os.Parcel _reply = android.os.Parcel.obtain();int _result;try {_data.writeInterfaceToken(DESCRIPTOR);_data.writeString(orderId);_data.writeString(productName);_data.writeFloat(money);mRemote.transact(Stub.TRANSACTION_pay, _data, _reply, 0);_reply.readException();_result = _reply.readInt();}finally {_reply.recycle();_data.recycle();}return _result;}}static final int TRANSACTION_pay = (android.os.IBinder.FIRST_CALL_TRANSACTION + 0);}public int pay(java.lang.String orderId, java.lang.String productName, float money) throws android.os.RemoteException;}

       第二步：服务端定义一个service实现支付接口

/** *  */package com.figo.study.aidl;import android.app.Service;import android.content.Intent;import android.os.IBinder;import android.os.RemoteException;import android.util.Log;/** * @author figo * */public class AidlTestService extends Service {    String tag = "AidlTestService";    private AidlTestInterface.Stub mBinder = new AidlTestInterface.Stub() {        @Override        public int pay(String orderId, String productName, float money) throws RemoteException {            System.out.print("收到客户端请求的数据:" + orderId + "," + productName + "," + money);            Log.i(tag, "收到客户端请求的数据:" + orderId + "," + productName + "," + money);            return 1;        }    };    /* (non-Javadoc)     * @see android.app.Service#onBind(android.content.Intent)     */    @Override    public IBinder onBind(Intent intent) {        // TODO Auto-generated method stub        return mBinder;    }}

        第三步、服务端注册service

    <service android:name=".aidl.AidlTestService" >            <intent-filter>                <action android:name="com.figo.study.aidl.service" />                <category android:name="android.intent.category.DEFAULT" />            </intent-filter>    </service>

        好的，所谓的服务端，已经完成，下面开始客户端的工作。

        第四步、将服务端自动生成的Stub类（即aidl文件生成到gen文件夹下面的那个类）打成jar，添加到客户端libs文件夹，这步也可在客户端写一个相同包名下的aidl文件来完成。

       第五步、客户端通过aidl调用服务端的支付接口

         

/** *  */package com.study.aidlclient;import com.figo.study.aidl.AidlTestInterface;import android.app.Activity;import android.content.ComponentName;import android.content.Context;import android.content.Intent;import android.content.ServiceConnection;import android.os.AsyncTask;import android.os.Bundle;import android.os.IBinder;import android.os.RemoteException;import android.util.Log;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;/** * @author figo * */public class AidlTestClientActivity extends Activity {    private Button btnPay;    AidlTestInterface mAidlTestInterface;    String tag = "AidlTestClientActivity";    private ServiceConnection mConnection = new ServiceConnection() {        public void onServiceConnected(ComponentName className, IBinder service) {            mAidlTestInterface = AidlTestInterface.Stub.asInterface(service);            try {                Log.i(tag, "onServiceConnected,start to pay!");                new PayTask().execute(1);            } catch (Exception e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }        public void onServiceDisconnected(ComponentName className) {            mAidlTestInterface = null;        }    };    @Override    protected void onCreate(Bundle savedInstanceState) {        // TODO Auto-generated method stub        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_aidltest);        btnPay = (Button) findViewById(R.id.btn_pay);        btnPay.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                pay();            }        });    }    class PayTask extends AsyncTask<Integer, Integer, Boolean> {        @Override        protected Boolean doInBackground(Integer... params) {            // TODO Auto-generated method stub            int result = 0;            try {                result = mAidlTestInterface.pay("1234567890", "上饶鸡腿", 10f);            } catch (RemoteException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }            if (result == 1) {                Log.i(tag, "pay successful!");            }            return true;        }        @Override        protected void onPostExecute(Boolean result) {            // TODO Auto-generated method stub            super.onPostExecute(result);            //支付完成取消绑定服务            unbindService(mConnection);            Log.i(tag, "unbindService successful!");        }    };    private void pay() {        Intent intent = new Intent("com.figo.study.aidl.service");        //添加packageName避免Implicit intents with startService are not safe        intent.setPackage("com.figo.study");        bindService(intent, mConnection, Context.BIND_AUTO_CREATE);    }}