Android技术22：Android中AIDL

浏览数：50 / 时间：2015年06月11日

在Android中进程内部通过全局变量，文件，preference，数据库作为数据的载体实现数据共享和通信。然后在进程之间则需要借助Binder实现IPC调用。Android进程通信框架：服务端，客户端，Linux binder驱动。Binder驱动成为连接两端的桥梁。我们首先通过aidl语言实现一个简单的多进程通信。具体实现步骤如下：

1.定义aidl文件

IService.aidl,定义一个接口，test() ，不包含负责的类和数据。

1 package com.demo.ipc;
2 
3 interface IService{
4     void test();
5 }

2.在gen目录下自动生成响应java文件，其主要类下生成一个Stub,该类为抽象类，继承了IBinder类，主要作为服务端，用于接收服务请求，与客户端打交道。

 1 /*
 2  * This file is auto-generated.  DO NOT MODIFY.
 3  * Original file: D:\\Android\\ipc\\src\\com\\demo\\ipc\\IService.aidl
 4  */
 5 package com.demo.ipc;
 6 public interface IService extends android.os.IInterface
 7 {
 8 /** Local-side IPC implementation stub class. */
 9 public static abstract class Stub extends android.os.Binder implements com.demo.ipc.IService
10 {
11 private static final java.lang.String DESCRIPTOR = "com.demo.ipc.IService";
12 /** Construct the stub at attach it to the interface. */
13 public Stub()
14 {
15 this.attachInterface(this, DESCRIPTOR);
16 }
17 /**
18  * Cast an IBinder object into an com.demo.ipc.IService interface,
19  * generating a proxy if needed.
20  */
21 public static com.demo.ipc.IService asInterface(android.os.IBinder obj)
22 {
23 if ((obj==null)) {
24 return null;
25 }
26 android.os.IInterface iin = obj.queryLocalInterface(DESCRIPTOR);
27 if (((iin!=null)&&(iin instanceof com.demo.ipc.IService))) {
28 return ((com.demo.ipc.IService)iin);
29 }
30 return new com.demo.ipc.IService.Stub.Proxy(obj);
31 }
32 @Override public android.os.IBinder asBinder()
33 {
34 return this;
35 }
36 @Override public boolean onTransact(int code, android.os.Parcel data, android.os.Parcel reply, int flags) throws android.os.RemoteException
37 {
38 switch (code)
39 {
40 case INTERFACE_TRANSACTION:
41 {
42 reply.writeString(DESCRIPTOR);
43 return true;
44 }
45 case TRANSACTION_test:
46 {
47 data.enforceInterface(DESCRIPTOR);
48 this.test();
49 reply.writeNoException();
50 return true;
51 }
52 }
53 return super.onTransact(code, data, reply, flags);
54 }
55 private static class Proxy implements com.demo.ipc.IService
56 {
57 private android.os.IBinder mRemote;
58 Proxy(android.os.IBinder remote)
59 {
60 mRemote = remote;
61 }
62 @Override public android.os.IBinder asBinder()
63 {
64 return mRemote;
65 }
66 public java.lang.String getInterfaceDescriptor()
67 {
68 return DESCRIPTOR;
69 }
70 @Override public void test() throws android.os.RemoteException
71 {
72 android.os.Parcel _data = android.os.Parcel.obtain();
73 android.os.Parcel _reply = android.os.Parcel.obtain();
74 try {
75 _data.writeInterfaceToken(DESCRIPTOR);
76 mRemote.transact(Stub.TRANSACTION_test, _data, _reply, 0);
77 _reply.readException();
78 }
79 finally {
80 _reply.recycle();
81 _data.recycle();
82 }
83 }
84 }
85 static final int TRANSACTION_test = (android.os.IBinder.FIRST_CALL_TRANSACTION + 0);
86 }
87 public void test() throws android.os.RemoteException;
88 }

3.创建服务端RemoteService

重写onBind()方法。

 1 public class RemoteService extends Service {
 2 
 3     @Override
 4     public IBinder onBind(Intent intent) {
 5         return mBinder;
 6     }
 7     
 8     IService.Stub mBinder=new Stub() {
 9         
10         @Override
11         public void test() throws RemoteException {
12             Log.i("tag", "RemoteService--mBinder--add");
13             
14         }
15     };
16 
17 }

5.AndroidManifest.xml注册声明Service

1     <service android:name="com.demo.ipc.RemoteService" android:process=":remote">
2             <intent-filter>
3                 <action android:name="com.demo.ipc.RemoteService"/>
4             </intent-filter>
5         </service>

6.定义客户端

 1 package com.demo.ipc;
 2 
 3 import android.content.ComponentName;
 4 import android.content.Context;
 5 import android.content.Intent;
 6 import android.content.ServiceConnection;
 7 import android.os.Bundle;
 8 import android.os.IBinder;
 9 import android.os.RemoteException;
10 import android.support.v7.app.ActionBarActivity;
11 import android.util.Log;
12 import android.view.View;
13 import android.view.View.OnClickListener;
14 import android.widget.Button;
15 
16 public class MainActivity extends ActionBarActivity {
17 
18     private Button bt1,bt2;
19     private IService mService;
20     private boolean isOpen=false;
21     private ServiceConnection serviceConnection=new ServiceConnection() {
22         
23         @Override
24         public void onServiceDisconnected(ComponentName name) {
25             Log.i("tag", "MainActivity--ServiceConnextion--onServiceDisconnected");
26             mService=null;
27         }
28         
29         @Override
30         public void onServiceConnected(ComponentName name, IBinder service) {
31             Log.i("tag", "MainActivity--ServiceConnextion--onServiceConnected");
32             mService=IService.Stub.asInterface(service);
33         }
34     };
35     @Override
36     protected void onCreate(Bundle savedInstanceState) {
37         super.onCreate(savedInstanceState);
38         setContentView(R.layout.activity_main);
39         bt1=(Button) findViewById(R.id.bt1);
40         bt2=(Button) findViewById(R.id.bt2);
41         bt1.setOnClickListener(new OnClickListener() {
42             
43             @Override
44             public void onClick(View v) {
45                 if(!isOpen){
46                     bindService(new Intent("com.demo.ipc.RemoteService"), serviceConnection, Context.BIND_AUTO_CREATE);
47                 }else{
48                     unbindService(serviceConnection);
49                 }
50                 
51             }
52         });
53         bt2.setOnClickListener(new OnClickListener() {
54             
55             @Override
56             public void onClick(View v) {
57                 try {
58                     mService.test();
59                 } catch (RemoteException e) {
60                     e.printStackTrace();
61                 }
62                 
63             }
64         });
65     }
66     
67     
68 }