AndroidPermissions.kt

import android.content.Context
import com.gun0912.tedpermission.PermissionListener
import com.gun0912.tedpermission.TedPermission
import kotlinx.coroutines.experimental.CoroutineStart
import kotlinx.coroutines.experimental.async
import kotlinx.coroutines.experimental.suspendCancellableCoroutine
import timber.log.Timber
import java.util.ArrayList

fun <T> Context.withPermission(permission: String, block: () -> T) = async(start = CoroutineStart.LAZY) {
    return@async if (checkForPermission(permission)) block() else null
}

suspend fun Context.checkForPermission(permission: String): Boolean =
        suspendCancellableCoroutine {
            try {
                TedPermission.with(this)
                        .setPermissionListener(object : PermissionListener {
                            override fun onPermissionGranted() {
                                it.resume(true)
                            }

                            override fun onPermissionDenied(deniedPermissions: ArrayList<String>?) {
                                if (deniedPermissions?.contains(permission) != null)
                                    it.resume(false)
                                else
                                    it.resume(true)
                            }
                        })
                        .setPermissions(permission)
                        .check()
            }
            catch (e: Exception){
                Timber.e(e, "check permission failed")
            }
        }

// Usage:
context.withPermission(Manifest.permission.READ_PHONE_STATE) {
    (context.getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager).simSerialNumber
}