java简单实现AIDL进程通信

服务端项目

• 右键包名，新建一个Service，名称设为NameService，如下图：
  
  

对自动生成的代码，稍作调整，代码如下：

public class NameService extends Service {
   public NameService() {
   }

   @Override
   public IBinder onBind(Intent intent) {
       return null;
   }
}

AndroidManifest.xml文件里面会自动生成如下代码：

        <service
            android:name=".NameService"
            android:enabled="true"
            android:exported="true">service>

• 右键main文件夹，new 一个aidl文件
  

• 名为IGetNameInterface，代码如下：

// IGetNameInterface.aidl
package com.exp.service;

interface IGetNameInterface {
  String getInfo();
}

• 新建aidl文件后，完整目录如下：
  

• rebuild一下，在build目录下会生成IGetNameInterface.java文件，如下图：
  

• 看下IGetNameInterface.java完整内容：

/*
 * This file is auto-generated.  DO NOT MODIFY.
 */
package com.exp.service;
public interface IGetNameInterface extends android.os.IInterface
{
  /** Default implementation for IGetNameInterface. */
  public static class Default implements com.exp.service.IGetNameInterface
  {
    @Override public java.lang.String getInfo() throws android.os.RemoteException
    {
      return null;
    }
    @Override
    public android.os.IBinder asBinder() {
      return null;
    }
  }
  /** Local-side IPC implementation stub class. */
  public static abstract class Stub extends android.os.Binder implements com.exp.service.IGetNameInterface
  {
    private static final java.lang.String DESCRIPTOR = "com.exp.service.IGetNameInterface";
    /** Construct the stub at attach it to the interface. */
    public Stub()
    {
      this.attachInterface(this, DESCRIPTOR);
    }
    /**
     * Cast an IBinder object into an com.exp.service.IGetNameInterface interface,
     * generating a proxy if needed.
     */
    public static com.exp.service.IGetNameInterface asInterface(android.os.IBinder obj)
    {
      if ((obj==null)) {
        return null;
      }
      android.os.IInterface iin = obj.queryLocalInterface(DESCRIPTOR);
      if (((iin!=null)&&(iin instanceof com.exp.service.IGetNameInterface))) {
        return ((com.exp.service.IGetNameInterface)iin);
      }
      return new com.exp.service.IGetNameInterface.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
    {
      java.lang.String descriptor = DESCRIPTOR;
      switch (code)
      {
        case INTERFACE_TRANSACTION:
        {
          reply.writeString(descriptor);
          return true;
        }
        case TRANSACTION_getInfo:
        {
          data.enforceInterface(descriptor);
          java.lang.String _result = this.getInfo();
          reply.writeNoException();
          reply.writeString(_result);
          return true;
        }
        default:
        {
          return super.onTransact(code, data, reply, flags);
        }
      }
    }
    private static class Proxy implements com.exp.service.IGetNameInterface
    {
      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 java.lang.String getInfo() throws android.os.RemoteException
      {
        android.os.Parcel _data = android.os.Parcel.obtain();
        android.os.Parcel _reply = android.os.Parcel.obtain();
        java.lang.String _result;
        try {
          _data.writeInterfaceToken(DESCRIPTOR);
          boolean _status = mRemote.transact(Stub.TRANSACTION_getInfo, _data, _reply, 0);
          if (!_status && getDefaultImpl() != null) {
            return getDefaultImpl().getInfo();
          }
          _reply.readException();
          _result = _reply.readString();
        }
        finally {
          _reply.recycle();
          _data.recycle();
        }
        return _result;
      }
      public static com.exp.service.IGetNameInterface sDefaultImpl;
    }
    static final int TRANSACTION_getInfo = (android.os.IBinder.FIRST_CALL_TRANSACTION + 0);
    public static boolean setDefaultImpl(com.exp.service.IGetNameInterface impl) {
      // Only one user of this interface can use this function
      // at a time. This is a heuristic to detect if two different
      // users in the same process use this function.
      if (Stub.Proxy.sDefaultImpl != null) {
        throw new IllegalStateException("setDefaultImpl() called twice");
      }
      if (impl != null) {
        Stub.Proxy.sDefaultImpl = impl;
        return true;
      }
      return false;
    }
    public static com.exp.service.IGetNameInterface getDefaultImpl() {
      return Stub.Proxy.sDefaultImpl;
    }
  }
  public java.lang.String getInfo() throws android.os.RemoteException;
}

• 这个接口里面，本身继承自IInterface。看看IInterface，里面就一个public IBinder asBinder();方法，如下：

package android.os;

/**
 * Base class for Binder interfaces.  When defining a new interface,
 * you must derive it from IInterface.
 */
public interface IInterface
{
    /**
     * Retrieve the Binder object associated with this interface.
     * You must use this instead of a plain cast, so that proxy objects
     * can return the correct result.
     */
    public IBinder asBinder();
}

• 除了上面父类的asBinder方法，本接口里面有一个静态共有类Default，一个静态抽象类Stub，还有我们定义的一个抽象方法getInfo()。
  

• 有了这个接口，就可以修改NameService的onBind()方法了，修改后完整代码如下：

public class NameService extends Service {
    private static final String TAG = "NameService";
    public NameService() {
    }

    @Override
    public IBinder onBind(Intent intent) {
        return new IGetNameInterface.Stub() {
            @Override
            public String getInfo() throws RemoteException {
                Log.e(TAG, "远程服务被调用");
                return "zhangjin";
            }
        };
    }
}

服务端代码到此就结束了。

客户端代码

• 把服务端整个aidl文件夹，复制过来，放在main目录下面，aidl文件不要修改。如下图：
  
• rebuild一下，会生成一个和服务端一样的文件：
  
• 在MainActivity中启动Service，并且显示数据。MainActivity布局文件自己写哈，其他代码如下：

public class MainActivity extends AppCompatActivity {
    private static final String TAG = "Client";
    private IGetNameInterface mGetNameService;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Intent intent = new Intent();
        intent.setComponent(new ComponentName("com.exp.service","com.exp.service.NameService"));
        bindService(intent, new ServiceConnection() {
            @Override
            public void onServiceConnected(ComponentName name, IBinder service) {
                Log.e(TAG, "onServiceConnected: ");
                try {
                    mGetNameService = IGetNameInterface.Stub.asInterface(service);
                    TextView tv = findViewById(R.id.tv);
                    tv.setText(mGetNameService.getInfo());
                } catch (Exception e) {
                    Log.e(TAG, "exception: " + e.getMessage());
                }
            }

            @Override
            public void onServiceDisconnected(ComponentName name) {
                Log.e(TAG, "onServiceDisconnected: ");
            }
        }, Context.BIND_AUTO_CREATE);
    }
}

安装测试

先安装service，再安装Client，看下效果：