Android AIDL 实例
为使应用程序之间能够彼此通信,Android提供了IPC (Inter Process Communication,进程间通信)的一种独特实现: AIDL (Android Interface Definition Language, Android接口定义语言)。
简单来说,AIDL 就是定义一个接口,客户端(调用端)通过 bindService 来与远程服务端建立一个连接,在该连接建立时会将返回一个 IBinder 对象,该对象是服务端 Binder 的 BinderProxy。在建立连接时,客户端通过 asInterface 函数将该 BinderProxy 对象包装成本地的 Proxy,并赋值给Proxy类的mRemote 字段,本地通过 mRemote 即可调用远程方法。
1、创建 .aidl 文件
首先打开 Android Studio,new 一个 AIDL file。具体代码如下 :
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); }
basicTypes 方法事接口自带的,不过可以知道,在 aidl 中只能使用这些基本类型参数:int, long, boolean, float,double , String ;
除了 basicTypes 方法之外,我们也可以添加自己的方法。因此,可以删除 basicTypes 方法,添加自己的方法。
二、生成 .java 文件
添加完方法之后,选中 .aidl 文件,在弹出的菜单中选择 Synchronize LocalAIDLS… Service.java,就会会自动帮你生成对应的 java 代码。
格式化代码之后,如下所示:
/* * This file is auto-generated. DO NOT MODIFY. * Original file: /Users/shenjiaqi/Documents/sjq/booksource/chapter6/DatabaseTest/app/src/main/aidl/com/example/databasetest/IMyAidlInterface.aidl */ package com.example.databasetest; public interface IMyAidlInterface extends android.os.IInterface { /** * Local-side IPC implementation stub class. */ public static abstract class Stub extends android.os.Binder implements com.example.databasetest.IMyAidlInterface { private static final java.lang.String DESCRIPTOR = "com.example.databasetest.IMyAidlInterface"; /** * Construct the stub at attach it to the interface. */ public Stub() { this.attachInterface(this, DESCRIPTOR); } /** * Cast an IBinder object into an com.example.databasetest.IMyAidlInterface interface, * generating a proxy if needed. */ public static com.example.databasetest.IMyAidlInterface asInterface(android.os.IBinder obj) { if ((obj == null)) { return null; } android.os.IInterface iin = obj.queryLocalInterface(DESCRIPTOR); if (((iin != null) && (iin instanceof com.example.databasetest.IMyAidlInterface))) { return ((com.example.databasetest.IMyAidlInterface) iin); } return new com.example.databasetest.IMyAidlInterface.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_basicTypes: { data.enforceInterface(DESCRIPTOR); int _arg0; _arg0 = data.readInt(); long _arg1; _arg1 = data.readLong(); boolean _arg2; _arg2 = (0 != data.readInt()); float _arg3; _arg3 = data.readFloat(); double _arg4; _arg4 = data.readDouble(); java.lang.String _arg5; _arg5 = data.readString(); this.basicTypes(_arg0, _arg1, _arg2, _arg3, _arg4, _arg5); reply.writeNoException(); return true; } } return super.onTransact(code, data, reply, flags); } private static class Proxy implements com.example.databasetest.IMyAidlInterface { 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; } /** * Demonstrates some basic types that you can use as parameters * and return values in AIDL. */ @Override public void basicTypes(int anInt, long aLong, boolean aBoolean, float aFloat, double aDouble, java.lang.String aString) throws android.os.RemoteException { android.os.Parcel _data = android.os.Parcel.obtain(); android.os.Parcel _reply = android.os.Parcel.obtain(); try { _data.writeInterfaceToken(DESCRIPTOR); _data.writeInt(anInt); _data.writeLong(aLong); _data.writeInt(((aBoolean) ? (1) : (0))); _data.writeFloat(aFloat); _data.writeDouble(aDouble); _data.writeString(aString); mRemote.transact(Stub.TRANSACTION_basicTypes, _data, _reply, 0); _reply.readException(); } finally { _reply.recycle(); _data.recycle(); } } } static final int TRANSACTION_basicTypes = (android.os.IBinder.FIRST_CALL_TRANSACTION + 0); } /** * Demonstrates some basic types that you can use as parameters * and return values in AIDL. */ public void basicTypes(int anInt, long aLong, boolean aBoolean, float aFloat, double aDouble, java.lang.String aString) throws android.os.RemoteException; }
如果,你需要修改 .aidl 文件,那么修改之后,选择 build -> make project 即可,会重新生成对应的java文件。
三、传输复杂数据
如果,需要传递复杂数据,那么就需要实现 Parcelable 接口,可序列化:
public class Info implements Parcelable { private String content; public String getContent() { return content; } public void setContent(String content) { this.content = content; } public Info() { } public Info(Parcel in) { content = in.readString(); } public static final Creator<Info> CREATOR = new Creator<Info>() { @Override public Info createFromParcel(Parcel in) { return new Info(in); } @Override public Info[] newArray(int size) { return new Info[size]; } }; @Override public int describeContents() { return 0; } @Override public void writeToParcel(Parcel dest, int flags) { dest.writeString(content); } /** * 参数是一个Parcel,用它来存储与传输数据 * * @param dest */ public void readFromParcel(Parcel dest) { //注意,此处的读值顺序应当是和writeToParcel()方法中一致的 content = dest.readString(); } //方便打印数据 @Override public String toString() { return "content : " + content; } }
与此同时,也要建一个 info.aidl 文件,表明数据也是可以传递的。
package com.viii.aidlclient; //注意:Info.Info.java的包名应当是一样的 //这个文件的作用是引入了一个序列化对象 Info 供其他的AIDL文件使用 //注意parcelable是小写 parcelable Info;
这样就可以使用 info 对象了。 不用在受前面的基本类型变量所控制。
四、建立 service
接下去,新建一个Service负责接收消息,并在AndroidManifest.xml里面注册 Service:
public class MyService extends Service { private static final String TAG = "MyService"; // private MyBinder mMyBinder = new MyBinder(); @Nullable @Override public IBinder onBind(Intent intent) { Log.d(TAG, "onBind: "); return null; } @Override public void onCreate() { Log.d(TAG, "onCreate: "); super.onCreate(); } @Override public int onStartCommand(Intent intent, int flags, int startId) { Log.d(TAG, "onStartCommand: "); return super.onStartCommand(intent, flags, startId); } private final IMyAidlInterface.Stub mBinder = new IMyAidlInterface.Stub() { @Override public void basicTypes(int anInt, long aLong, boolean aBoolean, float aFloat, double aDouble, String aString) throws RemoteException { } }; }
这时候,可以 basicTypes 方法添加具体函数代码,实现你想要的功能。
5、获取服务
接下去在mainactivity中进行绑定。
public class MainActivity extends AppCompatActivity { private static final String TAG = "MainActivity"; private IMyAidlInterface mService; private boolean mIsBound; private AdditionServiceConnection mServiceConnection; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); doBindService() ; }/** * bind service */ private void doBindService() { mServiceConnection = new AdditionServiceConnection(); Intent intent = new Intent(this, MyService.class); bindService(intent, mServiceConnection, BIND_AUTO_CREATE); } /** * unbind service */ private void doUnbindService() { if (mIsBound) { unbindService(mServiceConnection); mServiceConnection = null; mIsBound = false; } } /** * ServiceConection */ class AdditionServiceConnection implements ServiceConnection { @Override public void onServiceConnected(ComponentName name, IBinder service) { mService = IMyAidlInterface.Stub.asInterface((IBinder) service); mIsBound = true; try { //设置死亡代理 service.linkToDeath(mDeathRecipient, 0); } catch (RemoteException e) { e.printStackTrace(); } Log.d(TAG, "onServiceConnected: "); } @Override public void onServiceDisconnected(ComponentName name) { mService = null; mIsBound = false; Log.d(TAG, "onServiceDisconnected: "); } } /** * 监听Binder是否死亡 */ private IBinder.DeathRecipient mDeathRecipient = new IBinder.DeathRecipient() { @Override public void binderDied() { if (mService == null) { return; } mService.asBinder().unlinkToDeath(mDeathRecipient, 0); mService = null; //重新绑定 doBindService(); } }; @Override protected void onStop() { super.onStop(); doUnbindService(); } }
将远程服务的 binder 拿到之后,我们就可以调用相关方法实现自己的功能呢。
到这里,一个 AIDL 就被我们实现了。
具体实例代码见 :https://download.csdn.net/download/szengjiaqi/10613236