如果控制应用程序在后台运行，Android是否会在一分钟后强制销毁服务？

Question

似乎我是从应用程序启动服务，但未在onStartCommand方法中调用startForeground（），然后将应用程序置于后台，在一分钟后调用onDestroy回调并破坏了服务。

我在Android文档中的任何地方都没有看到此说明。相反，文档含糊地说，最终这种服务将被销毁。

注意onStartCommand方法返回START_STICKY。

任何建议将不胜感激。

后接服务代码；它旨在探索服务功能，而不是作为实际的生产应用程序。同样，编程有时会以不同的方式来做同一件事。我一直在尝试不同的方法以获得更多的见解。而且我对Android还很陌生；后悔天真地写了代码。

class IntegerCounting : Service() {
    companion object {
        var theCounter : Int = 0
    }
    private lateinit var mHandler: Handler
    private lateinit var mRunnable: Runnable

    override fun onBind(intent: Intent): IBinder? {
        throw UnsupportedOperationException("Not yet implemented")
    }

    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
        // Send a notification that service is started
        Toast.makeText(getApplicationContext(), "Service started.", Toast.LENGTH_SHORT).show()

        // Do a periodic task
        mHandler = Handler()
        mRunnable = Runnable { CountByOne() }
        mHandler.postDelayed(mRunnable, 500)

        return Service.START_STICKY
    }

    override fun onDestroy() {
        super.onDestroy()

        Toast.makeText(getApplicationContext(), "Service destroyed.", Toast.LENGTH_SHORT).show()
        mHandler.removeCallbacks(mRunnable)
    }

    override fun onTaskRemoved(rootIntent: Intent?) {
        Toast.makeText(getApplicationContext(), "On Task Removed called", Toast.LENGTH_SHORT).show()
    }

    // Custom method to do a task
    private fun CountByOne() {
        ++theCounter
        if (theCounter % 10 == 0) {
            Toast.makeText(getApplicationContext(), "count by one " + theCounter.toString(), Toast.LENGTH_SHORT).show()
        }
        //showSomeText(theCounter.toString())
        mHandler.postDelayed(mRunnable, 500)
    }
}

MainActivity类如下：

class MainActivity : AppCompatActivity() {
    // Here is how you find out if an Android service is running
    private fun isServiceRunning(serviceClass: Class<*>): Boolean {
        val activityManager = getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager

        // Loop through the running services
        for (service in activityManager.getRunningServices(Integer.MAX_VALUE)) {
            if (serviceClass.name == service.service.className) {
                // If the service is running then return true
                return true
            }
        }
        return false
    }

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

        // Variable to hold service class name
        val serviceClass = IntegerCounting::class.java

        // Notice the service class is defined here, so subsequently all
        // we need to access this service is this instance of Intent
        val intent = Intent(applicationContext, serviceClass)

        counterText = findViewById(R.id.counter)
        counterText.text = "Ready to start counting"

        val startButton: Button = findViewById(R.id.start_counting)
        val stopButton: Button = findViewById(R.id.stop_counting)
        val showStatus: Button = findViewById(R.id.show_status)

        startButton.setOnClickListener({
            if (!isServiceRunning(serviceClass)) {
                counterText.text = "Starting Integer Counter service"
                startService(intent)
            } else {
                counterText.text = "Integer Counter service already running"
            }
        })

        stopButton.setOnClickListener {
            if (isServiceRunning(serviceClass)) {
                counterText.text = "Stopping Integer Counter service"
                stopService(intent)
            } else {
                counterText.text = "Integer Counter service already stopped"
            }
        }

        showStatus.setOnClickListener({
            if (isServiceRunning(serviceClass)) {
                counterText.text = "Integer Counter service is running, counter: " +
                                    IntegerCounting.theCounter.toString()
            } else {
                counterText.text = "Integer Counter service is stopped, counter " +
                                    IntegerCounting.theCounter.toString()
            }
        })
    }
}

Answer 1

[如果您的应用目标大于android O，则当应用进入后台时，这是正常行为。要保持Service，请尝试将startForceground与Notification结合使用>

虽然应用程序位于前台，但它可以自由创建和运行前台和后台服务。当应用进入后台时，它会有几分钟的窗口，仍允许其创建和使用服务。在该窗口结束时，该应用程序被认为是空闲的。这时，系统停止应用程序的后台服务，就像该应用程序已调用服务的Service.stopSelf（）方法一样。

文档here