Kotlin实现定时任务（AlarmManager + BroadcastReceiver）

Posted 2022-05-05 Steven Jon

前言

android实现定时任务有很多种方式，为什么选择了AlarmManager + BroadcastReceiver呢？
因为AlarmManager是系统级别的闹钟服务，如果你的项目存在长时间在后台运行的定时任务，因为Android设备有自己的休眠策略，当长时间的无操作，设备会自动让CPU进入 休眠状态，这样就可能导致Timer中的定时任务无法正常运行！而AlarmManager则不存在这种情况，因为AlarmManager具有唤醒CPU的功能，可以保证每次需要执行特定任务时CPU都能正常工作。

正因如此，我将AlarmManager + BroadcastReceiver封装成一个TimeTask，可直接复制使用。

TimeTask.kt

增加权限~~

<uses-permission android:name="android.permission.SCHEDULE_EXACT_ALARM" />

class TimeTask<T : TimeTask.Task?>(context: Context, actionName: String, task: T) 

    private var mContext: Context?
    private val mActionName: String
    private var mReceiver: TimeTaskReceiver? = null
    private val mTask: T?

    companion object 
        private var mPendingIntent: PendingIntent? = null
    

    init 
        mContext = context
        mActionName = actionName
        mTask = task
        initReceiver(context, actionName)
    

    fun startLooperTask() 
        if (null != mTask) 
            mTask.exeTask()
            configureAlarmManager(mTask.period())
        
    

    fun stopLooperTask() 
        cancelAlarmManager()
    

    fun onClose() 
        mContext!!.unregisterReceiver(mReceiver)
        mContext = null
    

    @SuppressLint("ObsoleteSdkInt")
    private fun configureAlarmManager(time: Long) 
        val manager = mContext!!.getSystemService(Context.ALARM_SERVICE) as AlarmManager
        val pendIntent = pendingIntent
        when 
            Build.VERSION.SDK_INT >= Build.VERSION_CODES.M -> 
                manager.setExactAndAllowWhileIdle(
                    AlarmManager.ELAPSED_REALTIME_WAKEUP,
                    SystemClock.elapsedRealtime() + time,
                    pendIntent
                )
            
            Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT -> 
                manager.setExact(
                    AlarmManager.ELAPSED_REALTIME_WAKEUP,
                    SystemClock.elapsedRealtime() + time,
                    pendIntent
                )
            
            else -> 
                manager[AlarmManager.ELAPSED_REALTIME_WAKEUP,
                        SystemClock.elapsedRealtime() + time] = pendIntent
            
        
    

    @get:SuppressLint("UnspecifiedImmutableFlag")
    private val pendingIntent: PendingIntent?
        get() 
            if (mPendingIntent == null) 
                val requestCode = 0
                val intent = Intent()
                intent.action = mActionName
                when 
                    Build.VERSION.SDK_INT >= Build.VERSION_CODES.S -> 
                        mPendingIntent = PendingIntent.getBroadcast(
                            mContext, requestCode, intent,
                            PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_MUTABLE
                        )
                    
                    else -> 
                        mPendingIntent = PendingIntent.getBroadcast(
                            mContext,
                            requestCode,
                            intent,
                            PendingIntent.FLAG_UPDATE_CURRENT
                        )
                    
                
            
            return mPendingIntent
        

    private fun cancelAlarmManager() 
        val manager = mContext!!.getSystemService(Context.ALARM_SERVICE) as AlarmManager
        manager.cancel(pendingIntent)
    

    private fun initReceiver(context: Context, actionName: String) 
        mReceiver = TimeTaskReceiver()
        val intentFilter = IntentFilter()
        intentFilter.addAction(actionName)
        context.registerReceiver(mReceiver, intentFilter)
    

    internal inner class TimeTaskReceiver : BroadcastReceiver() 
        override fun onReceive(context: Context, intent: Intent) 
            startLooperTask()
        
    

    interface Task 
        fun period(): Long 
            // 默认时间5S
            return 5000L
        

        fun exeTask()
    

使用方式

//比如在Activity中
class GatewayActivity : AppCompatActivity() 

    private lateinit var tt : TimeTask<TimeTask.Task>

    override fun onCreate(savedInstanceState: Bundle?) 
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_gateway)

        tt = TimeTask(this, "abc", object : TimeTask.Task 
            override fun exeTask() 
                LogUtils.debugInfo("exeTask>>>>>>>>>>>>")
            
        )

        findViewById<TextView>(R.id.tv).setOnClickListener 
            tt.startLooperTask()
        

        findViewById<TextView>(R.id.tvs).setOnClickListener 
            tt.stopLooperTask()
        

    

    override fun onDestroy() 
        super.onDestroy()
        tt.onClose()
    

注意！！！
如果需要修改定时任务的时间间隔，可以重写TimeTask.Task中的period()方法：

        tt = TimeTask(this, "abc", object : TimeTask.Task 

            // 从API 19开始，最小执行时间是5S，如果小于5S，则设置无效，还是按照5S周期执行
            override fun period(): Long 
                return 10000L
            

            override fun exeTask() 
                LogUtils.debugInfo("exeTask>>>>>>>>>>>>")
            
        )

日志打印，Android 9 & Android 12测试输出：

2022-05-03 13:46:26.188 22817-22817/com.jon.gateway D/JetpackMvvm: exeTask>>>>>>>>>>>>
2022-05-03 13:46:36.224 22817-22817/com.jon.gateway D/JetpackMvvm: exeTask>>>>>>>>>>>>
2022-05-03 13:46:46.244 22817-22817/com.jon.gateway D/JetpackMvvm: exeTask>>>>>>>>>>>>
2022-05-03 13:46:56.256 22817-22817/com.jon.gateway D/JetpackMvvm: exeTask>>>>>>>>>>>>
2022-05-03 13:47:06.270 22817-22817/com.jon.gateway D/JetpackMvvm: exeTask>>>>>>>>>>>>
2022-05-03 13:47:16.283 22817-22817/com.jon.gateway D/JetpackMvvm: exeTask>>>>>>>>>>>>

非常感谢你能看到最后，如果能够帮助到你，是我的荣幸！