test1/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 {
    public final static String ACTION_STRING_NAME = "sync_action_type";

    public final static int ACTION_START_SYNC = 0;

    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";

    public final static String GTASK_SERVICE_BROADCAST_IS_SYNCING = "isSyncing";

    public final static String GTASK_SERVICE_BROADCAST_PROGRESS_MSG = "progressMsg";

    private static GTaskASyncTask mSyncTask = null;

    private static String mSyncProgress = "";

    private void startSync() {
        if (mSyncTask == null) {
            mSyncTask = new GTaskASyncTask(this, new GTaskASyncTask.OnCompleteListener() {
                public void onComplete() {
                    mSyncTask = null;
                    sendBroadcast("");
                    stopSelf();
                }
            });
            sendBroadcast("");
            mSyncTask.execute();
        }
    }

    private void cancelSync() {
        if (mSyncTask != null) {
            mSyncTask.cancelSync();
        }
    }

    @Override
    public void onCreate() {
        mSyncTask = null;
    }

    @Override
    // 定义一个服务，它重写了onStartCommand方法来处理不同的启动命令
    public class GTaskSyncService extends Service {

        // 常量定义，用于在Intent中传递动作字符串
        private static final String ACTION_STRING_NAME = "action_string_name"; // 动作字符串的键
        private static final int ACTION_INVALID = -1; // 无效的动作值
        private static final int ACTION_START_SYNC = 0; // 开始同步的动作值
        private static final int ACTION_CANCEL_SYNC = 1; // 取消同步的动作值

        // 同步任务的状态
        private static SyncTask mSyncTask; // 假设SyncTask是一个处理同步任务的类
        private static String mSyncProgress; // 同步进度的字符串

        // 当服务接收到启动命令时调用
        @Override
        public int onStartCommand(Intent intent, int flags, int startId) {
            Bundle bundle = intent.getExtras(); // 从Intent中获取附加数据
            if (bundle != null && bundle.containsKey(ACTION_STRING_NAME)) { // 检查是否有动作字符串
                switch (bundle.getInt(ACTION_STRING_NAME, ACTION_INVALID)) { // 根据动作值执行相应操作
                    case ACTION_START_SYNC:
                        startSync(); // 开始同步
                        break;
                    case ACTION_CANCEL_SYNC:
                        cancelSync(); // 取消同步
                        break;
                    default:
                        break;
                }
                return START_STICKY; // 如果服务被杀死，系统会重新创建服务并调用onStartCommand
            }
            return super.onStartCommand(intent, flags, startId); // 如果没有动作字符串，调用父类的实现
        }

        // 当系统内存低时调用
        @Override
        public void onLowMemory() {
            if (mSyncTask != null) {
                mSyncTask.cancelSync(); // 如果有同步任务在运行，取消它
            }
        }

        // 服务不支持绑定，因此返回null
        @Override
        public IBinder onBind(Intent intent) {
            return null;
        }

        // 发送一个广播，包含同步进度信息
        public void sendBroadcast(String msg) {
            mSyncProgress = msg; // 更新同步进度
            Intent intent = new Intent(GTASK_SERVICE_BROADCAST_NAME); // 创建一个新的Intent用于广播
            intent.putExtra(GTASK_SERVICE_BROADCAST_IS_SYNCING, mSyncTask != null); // 添加是否正在同步的信息
            intent.putExtra(GTASK_SERVICE_BROADCAST_PROGRESS_MSG, msg); // 添加同步进度的信息
            sendBroadcast(intent); // 发送广播
        }

        // 从Activity启动同步服务的方法
        public static void startSync(Activity activity) {
            GTaskManager.getInstance().setActivityContext(activity); // 设置活动上下文给任务管理器
            Intent intent = new Intent(activity, GTaskSyncService.class); // 创建一个新的Intent指向服务
            intent.putExtra(GTaskSyncService.ACTION_STRING_NAME, GTaskSyncService.ACTION_START_SYNC); // 添加开始同步的动作
            activity.startService(intent); // 启动服务
        }

        // 从Context取消同步服务的方法
        public static void cancelSync(Context context) {
            Intent intent = new Intent(context, GTaskSyncService.class); // 创建一个新的Intent指向服务
            intent.putExtra(GTaskSyncService.ACTION_STRING_NAME, GTaskSyncService.ACTION_CANCEL_SYNC); // 添加取消同步的动作
            context.startService(intent); // 启动服务
        }

        // 检查是否正在同步的方法
        public static boolean isSyncing() {
            return mSyncTask != null; // 返回同步任务是否非空
        }

        // 获取同步进度字符串的方法
        public static String getProgressString() {
            return mSyncProgress; // 返回同步进度字符串
        }
    }