android-testing-runtime-permissions-on-grant-permission

MainActivity.java

public void onGrantPermission(View view) {  
    if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.READ_CONTACTS)) {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_CONTACTS},
                    REQ_CODE_PERMISSIONS_READ_CONTACTS);
    } else {
        goToSettings();
    }
}

private void goToSettings() {  
    Uri uri = Uri.fromParts("package", getPackageName(), null);
    Intent settingsIntent = new Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS, uri);
    settingsIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    startActivity(settingsIntent);
}