什么是销售型网站,wordpress搜索字段,织梦多个网站,星子网本文转自#xff1a;http://xwangly.iteye.com/blog/1109424 Messenger:信使 官方文档解释#xff1a;它引用了一个Handler对象#xff0c;以便others能够向它发送消息(使用mMessenger.send(Message msg)方法)。该类允许跨进程间基于Message的通信(即两个进程间可以通过Mess…本文转自http://xwangly.iteye.com/blog/1109424 Messenger:信使 官方文档解释它引用了一个Handler对象以便others能够向它发送消息(使用mMessenger.send(Message msg)方法)。该类允许跨进程间基于Message的通信(即两个进程间可以通过Message进行通信)在服务端使用Handler创建一个Messenger客户端持有这个Messenger就可以与服务端通信了。 以前我们使用HandlerMessage的方式进行通信都是在同一个进程中从线程持有一个主线程的Handler对象并向主线程发送消息。 而Android既然可以使用bindler机制进行跨进行通信所以我们当然可以将Handler与bindler结合起来进行跨进程发送消息。 查看API就可以发现Messenger就是这种方式的实现。 一般使用方法如下 。远程通过 Java代码 mMessenger new Messenger(mHandler) mMessenger new Messenger(mHandler) 创建一个信使对象 。客户端使用bindlerService请求连接远程 。远程onBind方法返回一个bindler Java代码 return mMessenger.getBinder(); return mMessenger.getBinder(); 4.客户端使用远程返回的bindler得到一个信使即得到远程信使 Java代码 public void onServiceConnected(ComponentName name, IBinder service) { rMessenger new Messenger(service); ...... } public void onServiceConnected(ComponentName name, IBinder service) {rMessenger new Messenger(service);......} 这里虽然是new了一个Messenger但我们查看它的实现 Java代码 /** * Create a Messenger from a raw IBinder, which had previously been * retrieved with {link #getBinder}. * * param target The IBinder this Messenger should communicate with. */ public Messenger(IBinder target) { mTarget IMessenger.Stub.asInterface(target); } /*** Create a Messenger from a raw IBinder, which had previously been* retrieved with {link #getBinder}.* * param target The IBinder this Messenger should communicate with.*/public Messenger(IBinder target) {mTarget IMessenger.Stub.asInterface(target);} 发现它的mTarget是通过Aidl得到的实际上就是远程创建的那个。 。客户端可以使用这个远程信使对象向远程发送消息rMessenger.send(msg); 这样远程服务端的Handler对象就能收到消息了然后可以在其handlerMessage(Message msg)方法中进行处理。该Handler对象就是第一步服务端创建Messenger时使用的参数mHandler. 经过这个步骤貌似只有客户端向服务端发送消息这样的消息传递是单向的那么如何实现双向传递呢 首先需要在第步稍加修改在send(msg)前通过msm.replyTo mMessenger将自己的信使设置到消息中这样服务端接收到消息时同时也得到了客户端的信使对象了然后服务端可以通过 Java代码 //得到客户端的信使对象并向它发送消息 cMessenger msg.replyTo; cMessenger.send(message); //得到客户端的信使对象并向它发送消息
cMessenger msg.replyTo;
cMessenger.send(message); 即完成了从服务端向客户端发送消息的功能这样客服端可以在自己的Handler对象的handlerMessage方法中接收服务端发送来的message进行处理。 双向通信宣告完成。 下面改写ApiDemos工程实现Messenger通信 MessengerService.java Java代码 package com.xwangly.apidemo.app; import java.util.Random; import android.app.Service; import android.content.Intent; import android.os.Handler; import android.os.IBinder; import android.os.Message; import android.os.Messenger; import android.os.RemoteException; import android.util.Log; public class MessengerService extends Service { private String TAG MessengerService; Override public void onDestroy() { // TODO Auto-generated method stub Log.i(TAG, onDestroy); cMessenger null; super.onDestroy(); } Override public boolean onUnbind(Intent intent) { // TODO Auto-generated method stub Log.i(TAG, onUnbind); return super.onUnbind(intent); } static final int MSG_REGISTER_CLIENT 1; static final int MSG_UNREGISTER_CLIENT 2; static final int MSG_SET_VALUE 3; private Random random new Random(); private Handler mHandler new Handler() { Override public void handleMessage(Message msg) { // TODO Auto-generated method stub Log.i(TAG, handleMessage); switch (msg.what) { case MSG_SET_VALUE: try { Message message Message.obtain(null, MessengerService.MSG_SET_VALUE); message.arg1 random.nextInt(100); //得到客户端的信使对象并向它发送消息 cMessenger msg.replyTo; cMessenger.send(message); } catch (RemoteException e) { // TODO Auto-generated catch block e.printStackTrace(); } break; default: super.handleMessage(msg); } } }; /** * 自己的信使对象 */ private Messenger mMessenger new Messenger(mHandler); /** * 客户的信使 */ private Messenger cMessenger; Override public IBinder onBind(Intent intent) { // TODO Auto-generated method stub Log.i(TAG, onBind); //返回自己信使的bindler,以供客户端通过这个bindler得到服务端的信使对象通过new Messenger(bindler) return mMessenger.getBinder(); } Override public void onRebind(Intent intent) { // TODO Auto-generated method stub Log.i(TAG, onRebind); } } package com.xwangly.apidemo.app;import java.util.Random;import android.app.Service;
import android.content.Intent;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.Messenger;
import android.os.RemoteException;
import android.util.Log;public class MessengerService extends Service {private String TAG MessengerService;Overridepublic void onDestroy() {// TODO Auto-generated method stubLog.i(TAG, onDestroy);cMessenger null;super.onDestroy();}Overridepublic boolean onUnbind(Intent intent) {// TODO Auto-generated method stubLog.i(TAG, onUnbind);return super.onUnbind(intent);}static final int MSG_REGISTER_CLIENT 1;static final int MSG_UNREGISTER_CLIENT 2;static final int MSG_SET_VALUE 3;private Random random new Random();private Handler mHandler new Handler() {Overridepublic void handleMessage(Message msg) {// TODO Auto-generated method stubLog.i(TAG, handleMessage);switch (msg.what) {case MSG_SET_VALUE:try {Message message Message.obtain(null,MessengerService.MSG_SET_VALUE);message.arg1 random.nextInt(100);//得到客户端的信使对象并向它发送消息cMessenger msg.replyTo;cMessenger.send(message);} catch (RemoteException e) {// TODO Auto-generated catch blocke.printStackTrace();}break;default:super.handleMessage(msg);}}};/*** 自己的信使对象*/private Messenger mMessenger new Messenger(mHandler);/*** 客户的信使*/private Messenger cMessenger;Overridepublic IBinder onBind(Intent intent) {// TODO Auto-generated method stubLog.i(TAG, onBind);//返回自己信使的bindler,以供客户端通过这个bindler得到服务端的信使对象通过new Messenger(bindler)return mMessenger.getBinder();}Overridepublic void onRebind(Intent intent) {// TODO Auto-generated method stubLog.i(TAG, onRebind);}}MessengerServiceActivities.java Java代码 package com.xwangly.apidemo.app; import com.xwangly.apidemo.R; import android.app.Activity; import android.content.ComponentName; import android.content.Intent; import android.content.ServiceConnection; import android.os.Bundle; import android.os.Handler; import android.os.IBinder; import android.os.Message; import android.os.Messenger; import android.os.RemoteException; import android.util.Log; import android.view.View; import android.widget.TextView; public class MessengerServiceActivities { public static class Binding extends Activity implements View.OnClickListener { private String TAG Binding; TextView mCallbackText; private boolean isBound; Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.messenger_service_binding); findViewById(R.id.bind).setOnClickListener(this); findViewById(R.id.unbind).setOnClickListener(this); mCallbackText (TextView) findViewById(R.id.callback); mCallbackText.setText(Not attached.); } private Handler mHandler new Handler() { Override public void handleMessage(Message msg) { Log.i(TAG, handleMessage); switch (msg.what) { case MessengerService.MSG_SET_VALUE: mCallbackText.setText(Received from service: msg.arg1); break; default: super.handleMessage(msg); } } }; /** * 自己的信使 */ private Messenger mMessenger; /** * 远程服务的信使 */ private Messenger rMessenger; private ServiceConnection connection new ServiceConnection() { public void onServiceConnected(ComponentName name, IBinder service) { // TODO Auto-generated method stub Log.i(TAG, onServiceConnected); rMessenger new Messenger(service); mMessenger new Messenger(mHandler); sendMessage(); } public void onServiceDisconnected(ComponentName name) { // TODO Auto-generated method stub rMessenger null; } }; public void onClick(View v) { // TODO Auto-generated method stub Intent intent new Intent( com.xwangly.apidemo.app.messenger_service); switch (v.getId()) { case R.id.bind: if (!isBound) { isBound bindService(intent, connection, BIND_AUTO_CREATE); //isBound true; }else { sendMessage(); } break; case R.id.unbind: if (isBound) { unbindService(connection); isBound false; } break; default: break; } } /** * 使用服务端的信使向它发送一个消息。 */ private void sendMessage() { // TODO Auto-generated method stub Message message Message.obtain(null, MessengerService.MSG_SET_VALUE); message.replyTo mMessenger; try { rMessenger.send(message); } catch (RemoteException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } } package com.xwangly.apidemo.app;import com.xwangly.apidemo.R;import android.app.Activity;
import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.Messenger;
import android.os.RemoteException;
import android.util.Log;
import android.view.View;
import android.widget.TextView;public class MessengerServiceActivities {public static class Binding extends Activity implementsView.OnClickListener {private String TAG Binding;TextView mCallbackText;private boolean isBound;Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.messenger_service_binding);findViewById(R.id.bind).setOnClickListener(this);findViewById(R.id.unbind).setOnClickListener(this);mCallbackText (TextView) findViewById(R.id.callback);mCallbackText.setText(Not attached.);}private Handler mHandler new Handler() {Overridepublic void handleMessage(Message msg) {Log.i(TAG, handleMessage);switch (msg.what) {case MessengerService.MSG_SET_VALUE:mCallbackText.setText(Received from service: msg.arg1);break;default:super.handleMessage(msg);}}};/*** 自己的信使*/private Messenger mMessenger;/*** 远程服务的信使*/private Messenger rMessenger;private ServiceConnection connection new ServiceConnection() {public void onServiceConnected(ComponentName name, IBinder service) {// TODO Auto-generated method stubLog.i(TAG, onServiceConnected);rMessenger new Messenger(service);mMessenger new Messenger(mHandler);sendMessage();}public void onServiceDisconnected(ComponentName name) {// TODO Auto-generated method stubrMessenger null;}};public void onClick(View v) {// TODO Auto-generated method stubIntent intent new Intent(com.xwangly.apidemo.app.messenger_service);switch (v.getId()) {case R.id.bind:if (!isBound) {isBound bindService(intent, connection, BIND_AUTO_CREATE);//isBound true;}else {sendMessage();}break;case R.id.unbind:if (isBound) {unbindService(connection);isBound false;}break;default:break;}}/*** 使用服务端的信使向它发送一个消息。*/private void sendMessage() {// TODO Auto-generated method stubMessage message Message.obtain(null, MessengerService.MSG_SET_VALUE);message.replyTo mMessenger;try {rMessenger.send(message);} catch (RemoteException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}}AndroidManifest.xml相关配置如下 Xml代码 service android:name.app.MessengerService intent-filter action android:namecom.xwangly.apidemo.app.messenger_service / /intent-filter /service activity android:name.app.MessengerServiceActivities$Binding android:labelstring/activity_messenger_service_binding android:launchModesingleTop intent-filter action android:nameandroid.intent.action.MAIN / category android:nameandroid.intent.category.LAUNCHER / /intent-filter /activity service android:name.app.MessengerService intent-filteraction android:namecom.xwangly.apidemo.app.messenger_service //intent-filter/serviceactivity android:name.app.MessengerServiceActivities$Bindingandroid:labelstring/activity_messenger_service_bindingandroid:launchModesingleTopintent-filteraction android:nameandroid.intent.action.MAIN /category android:nameandroid.intent.category.LAUNCHER //intent-filter/activity 至于layout就不帖了两个按钮一个文本域。 转载于:https://www.cnblogs.com/freeliver54/archive/2011/12/27/2303790.html
