MessagerService总结

时间：2022-01-28 12:16:44

一、整体工程图

MessagerService总结

二、messenger_service_binding.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:padding="4dip"

    android:gravity="center_horizontal"

    android:layout_width="match_parent" android:layout_height="match_parent">

    <TextView

        android:layout_width="match_parent" android:layout_height="wrap_content"

        android:layout_weight="0"

        android:paddingBottom="4dip"

        android:text="@string/messenger_service_binding"/>

    <Button android:id="@+id/bind"

        android:layout_width="wrap_content" android:layout_height="wrap_content"

        android:text="@string/bind_service">

        <requestFocus />

    </Button>

    <Button android:id="@+id/unbind"

        android:layout_width="wrap_content" android:layout_height="wrap_content"

        android:text="@string/unbind_service">

    </Button>

    <TextView android:id="@+id/callback"

        android:layout_width="match_parent" android:layout_height="wrap_content"

        android:layout_weight="0"

        android:gravity="center_horizontal" android:paddingTop="4dip"/>

</LinearLayout>

三、AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.jltxgcy.messengerservice"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk

        android:minSdkVersion="8"

        android:targetSdkVersion="15" />

    <application

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

        <activity

            android:name=".MessengerServiceActivities"

            android:label="@string/title_activity_messenger_service" >

            <intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

        <service

            android:name=".MessengerService">

        </service>

    </application>

</manifest>

四、MessengerServiceActivities.java

package com.jltxgcy.messengerservice;

import android.app.Activity;

import android.content.ComponentName;

import android.content.Context;

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.view.View.OnClickListener;

import android.widget.Button;

import android.widget.TextView;

import android.widget.Toast;

public class MessengerServiceActivities extends Activity{

        Messenger mServiceMessage = null;

        boolean mIsBound;

        TextView mCallbackText;

        class IncomingHandler extends Handler {

            @Override

            public void handleMessage(Message msg) {

                switch (msg.what) {

                    case MessengerService.MSG_SET_VALUE:

                        mCallbackText.setText("Received from service: " + msg.arg1);

                        break;

                    default:

                        super.handleMessage(msg);

                }

            }

        }

        final Messenger mMessenger = new Messenger(new IncomingHandler());

        private ServiceConnection mConnection = new ServiceConnection() {

            public void onServiceConnected(ComponentName className,

                    IBinder service) {

                mServiceMessage = new Messenger(service);

                mCallbackText.setText("Attached.");

                try {

                    Message msg = Message.obtain(null,

                            MessengerService.MSG_REGISTER_CLIENT);

                    msg.replyTo = mMessenger;

                    mServiceMessage.send(msg);

                    msg = Message.obtain(null,

                            MessengerService.MSG_SET_VALUE, this.hashCode(), 0);

                    mServiceMessage.send(msg);

                } catch (RemoteException e) {

                }

            }

            public void onServiceDisconnected(ComponentName className) {

                mServiceMessage = null;

                Log.d("jltxgcy", "onServiceDisconnected");

            }

        };

        void doBindService() {

            bindService(new Intent(MessengerServiceActivities.this,

                    MessengerService.class), mConnection, Context.BIND_AUTO_CREATE);

            mIsBound = true;

        }

        void doUnbindService() {

            if (mIsBound) {

                if (mServiceMessage != null) {

                    try {

                        Message msg = Message.obtain(null,

                                MessengerService.MSG_UNREGISTER_CLIENT);

                        msg.replyTo = mMessenger;

                        mServiceMessage.send(msg);

                    } catch (RemoteException e) {

                    }

                }

                unbindService(mConnection);

                mIsBound = false;

            }

        }

        @Override

        protected void onCreate(Bundle savedInstanceState) {

            super.onCreate(savedInstanceState);

            setContentView(R.layout.messenger_service_binding);

            Button button = (Button)findViewById(R.id.bind);

            button.setOnClickListener(mBindListener);

            button = (Button)findViewById(R.id.unbind);

            button.setOnClickListener(mUnbindListener);

            mCallbackText = (TextView)findViewById(R.id.callback);

        }

        private OnClickListener mBindListener = new OnClickListener() {

            public void onClick(View v) {

                doBindService();

            }

        };

        private OnClickListener mUnbindListener = new OnClickListener() {

            public void onClick(View v) {

                doUnbindService();

            }

        };

}

五、MessengerService.java

/*

 * Copyright (C) 2010 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.jltxgcy.messengerservice;

import java.util.ArrayList;

import android.app.NotificationManager;

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;

import android.widget.Toast;

public class MessengerService extends Service {

    private ArrayList<Messenger> mClients = new ArrayList<Messenger>();

    private int mValue = 0;

    public static final String TAG = "jltxgcy";

    public static final int MSG_REGISTER_CLIENT = 1;

    public static final int MSG_UNREGISTER_CLIENT = 2;

    public static final int MSG_SET_VALUE = 3;

    class IncomingHandler extends Handler {

        @Override

        public void handleMessage(Message msg) {

            switch (msg.what) {

                case MSG_REGISTER_CLIENT:

                    mClients.add(msg.replyTo);

                    break;

                case MSG_UNREGISTER_CLIENT:

                    mClients.remove(msg.replyTo);

                    break;

                case MSG_SET_VALUE:

                    mValue = msg.arg1;

                    for (int i=mClients.size()-1; i>=0; i--) {

                        try {

                            mClients.get(i).send(Message.obtain(null,

                                    MSG_SET_VALUE, mValue, 0));

                        } catch (RemoteException e) {

                            mClients.remove(i);

                        }

                    }

                    break;

                default:

                    super.handleMessage(msg);

            }

        }

    }

    final Messenger mMessenger = new Messenger(new IncomingHandler());

    @Override

    public void onCreate() {

    	Log.d(TAG, "onCreate");

    }

    @Override

    public void onDestroy() {

    	Log.d(TAG, "onDestroy");

    }

    @Override

    public IBinder onBind(Intent intent) {

    	Log.d(TAG, "onBind");

        return mMessenger.getBinder();

    }

	@Override

	public boolean onUnbind(Intent intent) {

		Log.d(TAG, "onUnbind");

		return super.onUnbind(intent);

	}

}

六、详解

点击Bind Service，Logcat显示如下：

MessagerService总结

Service中：final Messenger mMessenger = new Messenger(new IncomingHandler());      onBind方法中mMessenger.getBinder()

Activity中， final Messenger mMessenger = new Messenger(new IncomingHandler());     onServiceConnected中mServiceMessage = new Messenger(service);

onBind方法中返回一个IBinder对象，onServiceConnected中，通过IBinder对象获取到了Messager对象。再通过msg.replyTo建立通信。

点击Unbind Service，Logcat显示如下：

MessagerService总结

运行结果如下：

MessagerService总结

获取message的方法：

          1、Message msg =new Message();

                msg.arg1=x;

                msg.arg2=x;

                msg.obj=x;

                msg.replyTo=x;

                msg.what=x;

                msg.setData(Bundle bundle);

          2、Message msg =Messge.obtain(Handler h, int what, int arg1, int arg2, Object obj);

                msg.replyTo=x;

		              msg.setData(Bundle bundle);

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