git-xiaomibianqian/lhy/GTaskSyncService.java

/*
 * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net)
 *
 * 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 net.micode.notes.gtask.remote;

import android.app.Activity;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.os.IBinder;

public class GTaskSyncService extends Service {//service通常用作在后台处理耗时的逻辑，不用与用户进行交互，即使应用被销毁依然可以继续工作。
    public final static String ACTION_STRING_NAME = "sync_action_type";//定义一系列静态变量

    public final static int ACTION_START_SYNC = 0;//开始同步

    public final static int ACTION_CANCEL_SYNC = 1;

    public final static int ACTION_INVALID = 2;

    public final static String GTASK_SERVICE_BROADCAST_NAME = "net.micode.notes.gtask.remote.gtask_sync_service";//服务广播的名称

    public final static String GTASK_SERVICE_BROADCAST_IS_SYNCING = "isSyncing";

    public final static String GTASK_SERVICE_BROADCAST_PROGRESS_MSG = "progressMsg";//进程消息

    private static GTaskASyncTask mSyncTask = null;

    private static String mSyncProgress = "";

    private void startSync() {//开始同步
        if (mSyncTask == null) {
            mSyncTask = new GTaskASyncTask(this, new GTaskASyncTask.OnCompleteListener() {
                public void onComplete() {//实现了在GTaskASyncTask类中定义的接口onComplete( )
                    mSyncTask = null;
                    sendBroadcast("");
                    stopSelf();
                }
            });
            sendBroadcast("");
            mSyncTask.execute();
        }
    }

    private void cancelSync() {//取消同步
        if (mSyncTask != null) {
            mSyncTask.cancelSync();
        }
    }

    @Override
    public void onCreate() {
        mSyncTask = null;
    }//初始化一个service

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {//充当重启便签指令
        Bundle bundle = intent.getExtras();
        if (bundle != null && bundle.containsKey(ACTION_STRING_NAME)) {
            switch (bundle.getInt(ACTION_STRING_NAME, ACTION_INVALID)) {
                case ACTION_START_SYNC:
                    startSync();
                    break;
                case ACTION_CANCEL_SYNC:// 两种情况，开始同步或者取消同步
                    cancelSync();
                    break;
                default:
                    break;
            }
            return START_STICKY;
        }
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onLowMemory() {//发送广播
        if (mSyncTask != null) {
            mSyncTask.cancelSync();
        }
    }

    public IBinder onBind(Intent intent) {
        return null;
    }//service服务中的绑定操作

    public void sendBroadcast(String msg) {//发送广播内容
        mSyncProgress = msg;
        Intent intent = new Intent(GTASK_SERVICE_BROADCAST_NAME);
        intent.putExtra(GTASK_SERVICE_BROADCAST_IS_SYNCING, mSyncTask != null);
        intent.putExtra(GTASK_SERVICE_BROADCAST_PROGRESS_MSG, msg);
        sendBroadcast(intent);
    }

    public static void startSync(Activity activity) {//启动同步
        GTaskManager.getInstance().setActivityContext(activity);
        Intent intent = new Intent(activity, GTaskSyncService.class);
        intent.putExtra(GTaskSyncService.ACTION_STRING_NAME, GTaskSyncService.ACTION_START_SYNC);
        activity.startService(intent);
    }

    public static void cancelSync(Context context) {//取消同步
        Intent intent = new Intent(context, GTaskSyncService.class);
        intent.putExtra(GTaskSyncService.ACTION_STRING_NAME, GTaskSyncService.ACTION_CANCEL_SYNC);
        context.startService(intent);
    }

    public static boolean isSyncing() {
        return mSyncTask != null;
    }//判断当前是否处于同步状态

    public static String getProgressString() {
        return mSyncProgress;
    }//返回当前同步状态
}