Utility Class

Utility.java

package com.kgislias.messenger.util;

import android.Manifest;
import android.annotation.TargetApi;
import android.app.Activity;
import android.content.Context;
import android.content.DialogInterface;
import android.content.pm.PackageManager;
import android.os.Build;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AlertDialog;

/**
 * Created by admin on 15-11-2016.
 */
public class Utility {
    public static final int MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE = 123;
    @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
    public static boolean checkPermission(final Context context)
    {
        int currentAPIVersion = Build.VERSION.SDK_INT;
        if(currentAPIVersion>=android.os.Build.VERSION_CODES.M)
        {
            if (ContextCompat.checkSelfPermission(context, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                if (ActivityCompat.shouldShowRequestPermissionRationale((Activity) context, Manifest.permission.READ_EXTERNAL_STORAGE)) {
                    AlertDialog.Builder alertBuilder = new AlertDialog.Builder(context);
                    alertBuilder.setCancelable(true);
                    alertBuilder.setTitle("Permission necessary");
                    alertBuilder.setMessage("External storage permission is necessary");
                    alertBuilder.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                        @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
                        public void onClick(DialogInterface dialog, int which) {
                            ActivityCompat.requestPermissions((Activity) context, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE);
                        }
                    });
                    AlertDialog alert = alertBuilder.create();
                    alert.show();
                } else {
                    ActivityCompat.requestPermissions((Activity) context, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE);
                }
                return false;
            } else {
                return true;
            }
        } else {
            return true;
        }
    }
}