RequestHandler.java

package com.example.cosmic.androidappclasses;

import android.app.Activity;
import android.content.pm.PackageManager;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.widget.Toast;

/**
 * Created by ${cosmic} on 1/7/18.
 */

public class RequestHandler extends AppCompatActivity{

    private static final int PERMISSION_REQUEST_CODE = 1;

    public boolean checkPermission(){
        int result = ContextCompat.checkSelfPermission(getApplicationContext(), android.Manifest.permission.WRITE_EXTERNAL_STORAGE);
        return result == PackageManager.PERMISSION_GRANTED;
    }

    private void requestPermission() {
        if (ActivityCompat.shouldShowRequestPermissionRationale((Activity) getApplication().getApplicationContext(), android.Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
            Toast.makeText((Activity) getApplication().getApplicationContext(), "Write External Storage permission allows us to do store images. Please allow this permission in App Settings.", Toast.LENGTH_LONG).show();
        } else {
            ActivityCompat.requestPermissions((Activity) getApplication().getApplicationContext(), new String[]{android.Manifest.permission.WRITE_EXTERNAL_STORAGE}, PERMISSION_REQUEST_CODE);
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode)
        {
            case PERMISSION_REQUEST_CODE: {
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                } else {
                    Toast.makeText((Activity) getApplication().getApplicationContext(), "The app was not allowed to write to your storage. Hence, it cannot function properly. Please consider granting it this permission", Toast.LENGTH_LONG).show();
                }
            }
        }
    }

}