ask for permission to make a phone call on android

RuntimePermissionRequest.java

//Add before making a phone call
if (ActivityCompat.checkSelfPermission(
        MainActivity.this, Manifest.permission.CALL_PHONE)
        != PackageManager.PERMISSION_GRANTED) {
    if (ActivityCompat.shouldShowRequestPermissionRationale(MainActivity.this,
            Manifest.permission.CALL_PHONE)) {
        Toast.makeText(MainActivity.this, "I know you said no, but I'm asking again", Toast.LENGTH_SHORT).show();
    }
    ActivityCompat.requestPermissions(MainActivity.this,
            new String[]{Manifest.permission.CALL_PHONE},
            MY_PERMISSIONS_REQUEST_CALL_PHONE);
    return;
}
//End of addition

//Add this method to handle the result of the permission request
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
   switch (requestCode) {
       case MY_PERMISSIONS_REQUEST_CALL_PHONE: {
           if (grantResults.length > 0
                   && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
               Toast.makeText(MainActivity.this, "Permission was granted!",
Toast.LENGTH_SHORT).show();
               callForInfo();
           } else {
               Toast.makeText(MainActivity.this, "Permission was denied!", 
Toast.LENGTH_SHORT).show();
           }
       }
   }
}