Android学习之介绍Binder的简单使用

 public static IBinder getRemoteBinder(){
 try {
 Class<?> serviceManager = Class.forName("android.os.ServiceManager");
 Method getService = serviceManager.getMethod("getService", String.class);
 IBinder iBinder = (IBinder) getService.invoke(serviceManager.newInstance(), "InputService");

 if(iBinder==null){
 Log.e(PinyinIME.TAG,"getService InputService : is empty");
 printServerList();//打印系统所提供的所有服务
 }
 return iBinder;
 } catch (ClassNotFoundException e) {
 e.printStackTrace();
 } catch (NoSuchMethodException e) {
 e.printStackTrace();
 } catch (IllegalAccessException e) {
 e.printStackTrace();
 } catch (IllegalArgumentException e) {
 e.printStackTrace();
 } catch (InvocationTargetException e) {
 e.printStackTrace();
 } catch (InstantiationException e) {
 e.printStackTrace();
 }
 return null;
 }

//具体源码在android.os.ServiceManager
 /**
 * Returns a reference to a service with the given name.
 * 
 * @param name the name of the service to get
 * @return a reference to the service, or <code>null</code> if the service doesn't exist
 */
 public static IBinder getService(String name) {
 try {
 IBinder service = sCache.get(name);
 if (service != null) {
 return service;
 } else {
 return getIServiceManager().getService(name);
 }
 } catch (RemoteException e) {
 Log.e(TAG, "error in getService", e);
 }
 return null;
 }

class IServiceManager : public IInterface
{
public:
 DECLARE_META_INTERFACE(ServiceManager);

 /**
 * Retrieve an existing service, blocking for a few seconds
 * if it doesn't yet exist.
 */
 virtual sp<IBinder> getService( const String16& name) const = 0;

 /**
 * Retrieve an existing service, non-blocking.
 */
 virtual sp<IBinder> checkService( const String16& name) const = 0;

 /**
 * Register a service.
 */
 virtual status_t addService( const String16& name,
   const sp<IBinder>& service,
   bool allowIsolated = false) = 0;

 /**
 * Return list of all existing services.
 */
 virtual Vector<String16> listServices() = 0;

 enum {
 GET_SERVICE_TRANSACTION = IBinder::FIRST_CALL_TRANSACTION,
 CHECK_SERVICE_TRANSACTION,
 ADD_SERVICE_TRANSACTION,
 LIST_SERVICES_TRANSACTION,
 };
};

//上面C++层注册服务提供一个IBinder接口子类，需要实现onTransact方法
 virtual status_t onTransact(uint32_t code,
 const Parcel& data,
 Parcel* reply,
 uint32_t flags = 0)
 {
 LOGD("enter MyService onTransact and the code is %d", code);
 switch (code)
 {
 case BINDER_HANDLE:
 LOGD("MyService interface handle");
 reply->writeCString("handle reply");
 break;
 case BINDER_SET_SCREEN:
 LOGD("MyService interface set screen");
 reply->writeCString("set screen reply");
 break;
 case BINDER_SET_CHAR:
 {//call cb
 LOGD("MyService interface set char before");
 reply->writeCString("set char reply");
 cb = data.readStrongBinder();
 if (cb != NULL)
 {
 LOGD("MyService interface set char : %s", data.readCString());
 Parcel in, out;
 in.writeInterfaceToken(String16(BINDER_NAME));
 in.writeInt32(n++);
 in.writeString16(String16("This is a string."));
 cb->transact(1, in, &out, 0);
 show();
 }
 break;
 }
 default:
 return BBinder::onTransact(code, data, reply, flags);
 }
 return 0;
 }

 //当输入法被激活的时候，会调用onStartInputView（EditorInfo,boolean）
 Parcel data = Parcel.obtain();
 data.writeInt(editorInfo.inputType);
 data.writeInt(editorInfo.imeOptions);

 Log.d(TAG, "isActives:" + isActives);

 if (isActives) {
 if (mController != null) {
 mController.startInput(data, Parcel.obtain());
 } else {
 isNeedActives = true;
 tmp = data;
 mController = new Controller(remoteBinder,this);
 }
 } else {
 isNeedActives = true;
 tmp = data;
 if (mController != null) {
 mController.serviceConnection();
 } else {
 mController = new Controller(remoteBinder,this);
 }
 }

//这里我将两个int参数写入到Parce对象中开始进行通讯

/**
 * 开始输入
 * 
 * @param data
 * 写入输入类型和多功能
 * @param reply
 */
 public void startInput(final Parcel data, final Parcel reply) {
 Log.d(PinyinIME.TAG, getClass().getName() + ":\t startInput");

 if (!PinyinIME.isActives) {
 Log.d(PinyinIME.TAG, "not yet check success , start input failure");
 dealHandler.sendEmptyMessage(Constant.HANDER_RELINK);
 return;
 }

 new Thread(new Runnable() {
 @Override
 public void run() {
 if (remoteBinder != null && remoteBinder.isBinderAlive()) {
  try {
  if (remoteBinder.transact(
  Constant.INPUT_METHOD_ACTIVATION, data, reply,
  IBinder.FLAG_ONEWAY)) {
  PinyinIME.isNeedActives = false;
  Log.d(PinyinIME.TAG,
   "input method to activate, notify the success");
  } else {
  Log.d(PinyinIME.TAG,
   "input method to activate, notify the failure");
  }
  } catch (RemoteException e) {
  e.printStackTrace();
  } finally {
  data.recycle();
  reply.recycle();
  }
 }else{
  dealHandler.sendEmptyMessage(Constant.HANDER_RELINK);
 }
 }
 }).start();
 }

//code必须双方定义好，否则接收数据无法正常，
//第一个是我们装载的序列化数据，
//第二我们可以直接传个对象，最好一个是需要返回结果的标识，
//0代表需要返回内容,FLAG_ONEWAY单方面无需返回结果的标识

public boolean transact(int code, Parcel data, Parcel reply, int flags)
 throws RemoteException;

//首先我们得让远程输入法程序拥有属于自己的ibinder类。
package com.redfinger.inputmethod.server;

import com.android.inputmethod.pinyin.PinyinIME;

import android.annotation.SuppressLint;
import android.os.Binder;
import android.os.IBinder;
import android.os.IInterface;
import android.os.Parcel;
import android.os.RemoteException;
import android.util.Log;
import android.view.KeyEvent;

public interface InputBinder extends IInterface{

 public static class Stub extends Binder implements InputBinder{
 private static final java.lang.String DESCRIPTOR = "com.redfinger.inputmethod.service.InputBinder";
 public PinyinIME pinyinIME;

 public Stub(PinyinIME pinyinIME) {
 this.pinyinIME = pinyinIME;
 this.attachInterface(this, DESCRIPTOR);
 }

 public InputBinder asInterface(IBinder obj){
 if(obj == null){
 return null;
 }
 IInterface iInterface = obj.queryLocalInterface(DESCRIPTOR);
 if(iInterface!=null&&iInterface instanceof InputBinder){
 return (InputBinder)iInterface;
 }
 return new Stub.Proxy(obj);
 }

 @Override
 public IBinder asBinder() {
 return this;
 }

 @SuppressLint({ "NewApi", "Recycle" })
 @Override
 protected boolean onTransact(int code, Parcel data, Parcel reply,
 int flags) throws RemoteException {
 switch (code) {
 case Constant.CONNECTION_HANDSHAKE2:
 String dataString = data.readString();
 Log.d(PinyinIME.TAG, "The second handshake start [data = "+dataString +"]");
 if("CONNECTION_RESPONED".equals(dataString)){   
  Parcel parcel = Parcel.obtain();
  parcel.writeString("CONNECTION_FINISH");
  pinyinIME.getRemoteBinder().transact(Constant.CONNECTION_HANDSHAKE3, parcel, Parcel.obtain(), IBinder.FLAG_ONEWAY);
  PinyinIME.isActives = true;
  Log.d(PinyinIME.TAG, "The third handshake success");

  if (PinyinIME.isNeedActives) {
  PinyinIME.mController.startInput(pinyinIME.getTmp(), Parcel.obtain());
  }
  if (PinyinIME.isNeedCloseInputMethod) {
  PinyinIME.mController.finishInput();
  }

 }else{
  Log.d(PinyinIME.TAG, "The third handshake failure , agent connect ! ");
  PinyinIME.mController.serviceConnection();
 }
 break;
 case Constant.FUNCTION_INPUT:
 ....
 switch (keyCode) {
 case 14:
  pinyinIME.simulateKeyEventDownUp(KeyEvent.KEYCODE_DEL);
  return true;
 case 28:
  pinyinIME.simulateKeyEventDownUp(KeyEvent.KEYCODE_ENTER);
  return true;
 case 65:
  pinyinIME.requestHideSelfFromClient = true;
  pinyinIME.requestHideSelf(0);
  break;
 } 
 break;
 case Constant.CHARACTER_INPUT: 
 ....
 return true;
 case Constant.DISCONNECTION:
 ....
 break;
 case Constant.INPUT_METHOD_PLATFORM:
 ....
 break;
 }
 return super.onTransact(code, data, reply, flags);
 }

 public static class Proxy implements InputBinder{

 private android.os.IBinder mRemote;

 public Proxy(android.os.IBinder mRemote) {
 this.mRemote = mRemote;
 }
 @Override
 public IBinder asBinder() {
 return mRemote;
 }
 public java.lang.String getInterfaceDescriptor()
 {
 return DESCRIPTOR;
 }
 }
 static final int receiveChar = (android.os.IBinder.FIRST_CALL_TRANSACTION + 0);
 }
}

 //Parce类中提供了这样的一个方法，就是用于写入ibinder对象的。
 public final void writeStrongBinder(IBinder val) {
 nativeWriteStrongBinder(mNativePtr, val);
 }