[移动开发]Android Service 前台执行

在接收行情数据等特殊条件下，必须保证服务能够连续执行。可按以下步骤执行：（仅限于HUAWEI P10 Plus 及 HORNOR X10，其它机型未测试）

1. 在 AndroidManifest.xml 中增加权限：

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

2. 在 MainActivity#onCreate() 中设置服务为前台服务：

class MainActivity : AppCompatActivity() {
    //...
    override fun onCreate(savedInstanceState: Bundle?) {
        //...
        val intent = Intent(this, FjztService::class.java)
        startForegroundService(intent)
        //...
    }
    //...

3. 在 TestService#onCreate() 中添加代码：

class TestService : Service() {
    private lateinit var wakeLock: PowerManager.WakeLock
    private lateinit var serviceThread: Thread
    //...
    override fun onCreate() {
        super.onCreate()
        Log.i(TAG, "onCreate: ")
        createChannels()  // 创建通知渠道
        startForeground()  // 设置为前台服务

        // 防止休眠
        val pm = getSystemService(Context.POWER_SERVICE) as PowerManager
        wakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TestService::class.java.name)
        wakeLock.acquire()  // 强制永远不休眠！

        // 创建服务线程
        serviceThread = thread {
            //prepare....
            while (true) {
                //do something...
                showNotification(...)
                try {
                    TimeUnit.MINUTES.sleep(1)  // 暂停 1 分钟
                } catch (e: InterruptedException) {
                    break
                }
            }
            Log.i(TAG, "loopThread exit.")
        }
    }

    //...

    // 根据需要，创建多个通知渠道
    private fun createChannels() {
        val manager = getSystemService(NOTIFICATION_SERVICE) as NotificationManager
        val channelDescription = "channel description"
        val channelImportance = NotificationManager.IMPORTANCE_DEFAULT
        NotificationChannel("channel-0 ID", "channel-0 Name", channelImportance).also {
            it.description = channelDescription
            it.enableLights(true)
            //it.enableVibration(true)
            //it.vibrationPattern = longArrayOf(200, 200)
            manager.createNotificationChannel(it)
        }
        NotificationChannel("channel-1 ID", "channel-1 Name", channelImportance).also {
            it.description = channelDescription
            it.enableLights(true)
            //it.enableVibration(true)
            //it.vibrationPattern = longArrayOf(200, 200)
            manager.createNotificationChannel(it)
        }
        NotificationChannel("channel-2 ID", "channel-2 Name", channelImportance).also {
            it.description = channelDescription
            it.enableLights(true)
            it.enableVibration(true)
            it.vibrationPattern = longArrayOf(200, 200)
            manager.createNotificationChannel(it)
        }
    }

    // 通知编号，可以增长或不增长
    private var notifyIdx = 1

    private fun startForeground() {
        val notification = Notification.Builder(this.applicationContext, "channel-0 ID")
                .setContentText("ContentText: service start foreground.")
                .setContentTitle("ContentTitle: service start foreground")
                .setSmallIcon(R.drawable.ic_dialog_info)  //  .ic_menu_week)
                //.setAutoCancel(true)
                .build()
        startForeground(notifyIdx, notification)
        //notifyIdx += 1
    }

    private fun showNotification(...) {
        val intent = Intent(this, MainActivity::class.java).also {
            // 向Activity传递参数
            it.putExtra("param1", param1)
            it.putExtra("param2", param2)
            it.flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
        }
        val pendingIntent = PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT)
        val notification = Notification.Builder(this.applicationContext, "channel-0 ID")  // 选择适当通知渠道
            .setContentText("...")
            .setContentTitle("...")
            .setSmallIcon(R.drawable.ic_dialog_info)
            .setContentIntent(pendingIntent)
            .setAutoCancel(true)
            .build()
        //notification.flags |= Notification.FLAG_ONGOING_EVENT

        val manager = getSystemService(NOTIFICATION_SERVICE) as NotificationManager
        manager.notify(notifyIdx, notification)
        //notifyIdx += 1
    }

    override fun onDestroy() {
        super.onDestroy()
        serviceThread.interrupt()  // 中断服务线程
    }
}

4. 进入手机系统设置关闭高耗电提醒
   
5. 设置应用启动管理
   
6. 进入运行应用列表，下拉并松开