I need to ask permission for contacts and when application starts I\'m asking,in ViewModel part I need to call method which requires permission. I need to check permission is gr
I have reworked the solution. The PermissionRequester
object is everything you need to request permissions from any point where you have at least an application context. It uses its helper PermissionRequestActivity
to accomplish this job.
@Parcelize
class PermissionResult(val permission: String, val state: State) : Parcelable
enum class State { GRANTED, DENIED_TEMPORARILY, DENIED_PERMANENTLY }
typealias Cancellable = () -> Unit
private const val PERMISSIONS_ARGUMENT_KEY = "PERMISSIONS_ARGUMENT_KEY"
private const val REQUEST_CODE_ARGUMENT_KEY = "REQUEST_CODE_ARGUMENT_KEY"
object PermissionRequester {
private val callbackMap = ConcurrentHashMap) -> Unit>(1)
private var requestCode = 256
get() {
requestCode = field--
return if (field < 0) 255 else field
}
fun requestPermissions(context: Context, vararg permissions: String, callback: (List) -> Unit): Cancellable {
val intent = Intent(context, PermissionRequestActivity::class.java)
.putExtra(PERMISSIONS_ARGUMENT_KEY, permissions)
.putExtra(REQUEST_CODE_ARGUMENT_KEY, requestCode)
.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
context.startActivity(intent)
callbackMap[requestCode] = callback
return { callbackMap.remove(requestCode) }
}
internal fun onPermissionResult(responses: List, requestCode: Int) {
callbackMap[requestCode]?.invoke(responses)
callbackMap.remove(requestCode)
}
}
class PermissionRequestActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
if (savedInstanceState == null) {
requestPermissions()
}
}
private fun requestPermissions() {
val permissions = intent?.getStringArrayExtra(PERMISSIONS_ARGUMENT_KEY) ?: arrayOf()
val requestCode = intent?.getIntExtra(REQUEST_CODE_ARGUMENT_KEY, -1) ?: -1
when {
permissions.isNotEmpty() && requestCode != -1 -> ActivityCompat.requestPermissions(this, permissions, requestCode)
else -> finishWithResult()
}
}
override fun onRequestPermissionsResult(requestCode: Int, permissions: Array, grantResults: IntArray) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults)
val permissionResults = grantResults.zip(permissions).map { (grantResult, permission) ->
val state = when {
grantResult == PackageManager.PERMISSION_GRANTED -> State.GRANTED
ActivityCompat.shouldShowRequestPermissionRationale(this, permission) -> State.DENIED_TEMPORARILY
else -> State.DENIED_PERMANENTLY
}
PermissionResult(permission, state)
}
finishWithResult(permissionResults)
}
private fun finishWithResult(permissionResult: List = listOf()) {
val requestCode = intent?.getIntExtra(REQUEST_CODE_ARGUMENT_KEY, -1) ?: -1
PermissionRequester.onPermissionResult(permissionResult, requestCode)
finish()
}
}
Usage:
class MyViewModel(application: Application) : AndroidViewModel(application) {
private val cancelRequest: Cancellable = requestPermission()
private fun requestPermission(): Cancellable {
return PermissionRequester.requestPermissions(getApplication(), "android.permission.SEND_SMS") {
if (it.firstOrNull()?.state == State.GRANTED) {
Toast.makeText(getApplication(), "GRANTED", Toast.LENGTH_LONG).show()
} else {
Toast.makeText(getApplication(), "DENIED", Toast.LENGTH_LONG).show()
}
}
}
override fun onCleared() {
super.onCleared()
cancelRequest()
}
}