title: AlertDialog Cannot Resolve Symbol
body: <p>I trying to Add an AlertDialog to my Android App, it show a several "Cannot Resolve Symbol". See the image (The errors marked Red).</p>
  
  <p><img src="https://i.stack.imgur.com/h2nhK.png" alt="Image Here"></p>
  
  <p><strong>Alert Dialog :</strong> </p>
  
  <pre><code> AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();
  alertDialog.setTitle("Alert");
  alertDialog.setMessage("Alert message to be shown");
  alertDialog.setButton(AlertDialog.BUTTON_NEUTRAL, "OK",
              new DialogInterface.OnClickListener() {
          public void onClick(DialogInterface dialog, int which) {
              dialog.dismiss();
          }
      });
  alertDialog.show();
  </code></pre>