Android Binder入门学习笔记

// 声明买票接口
public interface ITicket {
 boolean buyTicket();
}

// 官方的12306
public class Real12306 implements ITicket {
 @Override
 public boolean buyTicket() {
  if (抢票成功) return true;
  return false;
 }
}

// 第三方抢票软件
public class ThirdParty12306 implements ITicket {

 private Real12306 real12306;
 
 public ThirdParty12306(Real12306 real12306) {
  this.real12306 = real12306;
 }
 
 @Override
 public boolean buyTicket() {
  while (true) {
   if (real12306.buyTicket()) {
    return true;
   }
   // 10ms查询一次结果
   try {
    Thread.sleep(10);
   } catch (InterruptedException e) {
    e.printStackTrace();
   }
  }
 }
}

public class Main {

 public static void main(String[] args) {

  // 初始化我们的购票信息
  Real12306 real12306 = new Real12306();
  
  ThirdParty12306 thirdParty12306 = new ThirdParty12306(real12306);
  
  // 开始不断抢票，释放我们的劳动力
  thirdParty12306.buyTicket();
 }
}

package example.com.aidl;
interface IMath {
 int add(int a, int b);
}

class RemoteService : Service() {

 val math = Math()

 override fun onCreate() {
  super.onCreate()
  Log.d(TAG, "onCreate")
 }
 
 override fun onBind(intent: Intent): IBinder {
  return math
 }

 inner class Math : IMath.Stub() {
  override fun add(a: Int, b: Int): Int {
   return a + b
  }

 }
}

// 定义ServiceConnection类
inner class MyServiceConnection : ServiceConnection {
 override fun onServiceDisconnected(name: ComponentName?) {
  Log.d(TAG, "onServiceDisconnected")
 }

 override fun onServiceConnected(name: ComponentName?, service: IBinder?) {
  if (service == null) return

  // 将IBinder转换成IMath
  math = IMath.Stub.asInterface(service)

  Log.d(TAG, "result is ${math.add(1, 2)}")
 }
}

// 在onCreate中绑定RemoteService
val intent = Intent(this, RemoteService::class.java)
bindService(intent, serviceConnection, Context.BIND_AUTO_CREATE)

// IMath.java
private static final java.lang.String DESCRIPTOR = "example.com.aidl.IMath";

public static example.com.aidl.IMath asInterface(android.os.IBinder obj) {
 if ((obj == null)) {
  return null;
 }
 android.os.IInterface iin = obj.queryLocalInterface(DESCRIPTOR);
 if (((iin != null) && (iin instanceof example.com.aidl.IMath))) {
  return ((example.com.aidl.IMath) iin);
 }
 return new example.com.aidl.IMath.Stub.Proxy (obj);
}

// Binder.java
public @Nullable IInterface queryLocalInterface(@NonNull String descriptor) {
 if (mDescriptor != null && mDescriptor.equals(descriptor)) {
  return mOwner;
 }
 return null;
}

// IMath.java
public Stub() {
 this.attachInterface(this, DESCRIPTOR);
}

// Binder.java
public void attachInterface(@Nullable IInterface owner, @Nullable String descriptor) {
 mOwner = owner;
 mDescriptor = descriptor;
}

return new example.com.aidl.IMath.Stub.Proxy(obj);

@Override
public int add(int a, int b) throws android.os.RemoteException {
 android.os.Parcel _data = android.os.Parcel.obtain();
 android.os.Parcel _reply = android.os.Parcel.obtain ();
 int _result;
 try {
  // 使用Parcel来写入数据以便于跨进程传输
  _data.writeInterfaceToken(DESCRIPTOR);
  _data.writeInt(a);
  _data.writeInt(b);
  
  // mRemote是在asInterface中获得的BinderProxy对象
  mRemote.transact(Stub.TRANSACTION_add, _data, _reply, 0);
  
  // 使用Parcel来接收返回值
  _reply.readException();
  _result = _reply.readInt();
 } finally {
  _reply.recycle();
  _data.recycle();
 }
 return _result;
}

@Override
public boolean onTransact(int code, android.os.Parcel data , android.os.Parcel reply, int flags) throws android.os.RemoteException {
 java.lang.String descriptor = DESCRIPTOR;
 switch(code) {
  case INTERFACE_TRANSACTION : {
   reply.writeString(descriptor);
   return true;
  } case TRANSACTION_add : {
   data.enforceInterface(descriptor);
   int _arg0;
   _arg0 = data.readInt();
   int _arg1;
   _arg1 = data.readInt();
   int _result = this.add(_arg0, _arg1);
   reply.writeNoException();
   reply.writeInt(_result);
   return true;
  } default: {
  return super.onTransact(code, data, reply, flags);
  }
 }
}