从设置返回应用程序后如何正确检查位置服务是否已打开

Question

我有一个应用程序，它应该在启动时检查位置服务是否打开或关闭。我尝试使用

AlerDialog

，并通过

Intent

将用户发送到设置，但它无法按照我的意愿工作。

我改变了方法，因为我想在用户从设置返回后检查位置服务，并写下以下功能：

    @Composable
private fun TEST() {

    val locationManager =
        LocalContext.current.getSystemService(Context.LOCATION_SERVICE) as LocationManager

    val locationPermissionLauncher = rememberLauncherForActivityResult(
        contract = ActivityResultContracts.StartActivityForResult(),
        onResult = {
            Log.i(TAG, "TEST: ${locationManager.isLocationEnabled}")
        })
    val context = LocalContext.current

    LaunchedEffect(key1 = true) {
        locationPermissionLauncher.launch(Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS))
    }
}

现在，这是个好方法吗？ Intent服务结果不能直接注册Activity吧？我该如何正确处理它？

Answer 1

LaunchedEffect 在这种情况下将不起作用，因为当您的应用程序返回前台时，它不会再次触发。相反，您可以观察 Jetpack Compose 中的活动生命周期方法，如下所示：

val lifecycleOwner = LocalLifecycleOwner.current
val lifecycleState by lifecycleOwner.lifecycle.currentStateFlow.collectAsState()

val isPermissionGranted = 
    ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) 
       == PackageManager.PERMISSION_GRANTED


if(!isPermissionGranted) {
    // setup rememberLauncherForActivityResult
    // launch Activity
}

LaunchedEffect(lifecycleState) {
    if (lifecycleState == Lifecycle.State.RESUMED ) {
        // Activity was resumed. This is called when user returns to App.
        // Check here again whether the permission is granted now.
    )
}