package com.example.flashlight

import android.content.Context
import android.hardware.camera2.CameraAccessException
import android.hardware.camera2.CameraManager
import android.os.Bundle
import android.os.Handler
import android.os.Looper
import androidx.appcompat.app.AppCompatActivity

class MainActivity : AppCompatActivity() {
    var flashLightStatus: Boolean = false

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

        while (true) {
            Handler(Looper.getMainLooper()).postDelayed({
                //Do something after 100ms
                closeFlashLight()
            }, 5000)
            Handler(Looper.getMainLooper()).postDelayed({
                //Do something after 100ms
                openFlashLight()
            }, 5000)
        }
    }

    private fun openFlashLight() {
        val cameraManager = getSystemService(Context.CAMERA_SERVICE) as CameraManager
        val cameraId = cameraManager.cameraIdList[0]
        if (!flashLightStatus) {
            try {
                cameraManager.setTorchMode(cameraId, true)
                flashLightStatus = true

            } catch (e: CameraAccessException) {
            }
        } else {
            try {
                cameraManager.setTorchMode(cameraId, false)
                flashLightStatus = false
            } catch (e: CameraAccessException) {
            }
        }
    }

    private fun closeFlashLight()
    {
        val cameraManager = getSystemService(Context.CAMERA_SERVICE) as CameraManager
        val cameraId = cameraManager.cameraIdList[0]
        if (flashLightStatus) {
            try {
                cameraManager.setTorchMode(cameraId, false)
                flashLightStatus = false

            } catch (e: CameraAccessException) {
            }
        } else {
            try {
                cameraManager.setTorchMode(cameraId, true)
                flashLightStatus = true
            } catch (e: CameraAccessException) {
            }
        }
    }
}

这现在只需要打开手机上的手电筒，手电筒一直保持打开状态，因为while(true)

while (true) {
            Handler(Looper.getMainLooper()).postDelayed({
                //Do something after 100ms
                closeFlashLight()
            }, 5000)
            Handler(Looper.getMainLooper()).postDelayed({
                //Do something after 100ms
                openFlashLight()
            }, 5000)
        }

但如果我移除while true并只执行：

openFlashLight()
        Handler(Looper.getMainLooper()).postDelayed({
            //Do something after 100ms
            closeFlashLight()
        }, 5000)

这将打开手电筒，并将等待5秒钟，然后将关闭手电筒。但是我想做一些无穷无尽的东西，它会打开闪光灯，等待5秒，关闭闪光灯，等待5秒，打开闪光灯，等待5秒，关闭。
一直往那边走。每5秒开启/关闭一次，不间断。这就是为什么我试图使用while(true)，但手电筒只是保持开放不停。