How to make a simple Android popup window

This is a fuller example. It is a supplemental answer that deals with creating a popup window in general and not necessarily the specific details of the OP’s problem. (The OP asks for a cancel button, but this is not necessary because the user can click anywhere on the screen to cancel it.) It will look like the following image.

Make a layout for the popup window

Add a layout file to res/layout that defines what the popup window will look like.

popup_window.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="#62def8">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:layout_margin="30dp"
        android:textSize="22sp"
        android:text="This is a popup window."/>

</RelativeLayout>

Inflate and show the popup window

Here is the code for the main activity of our example. Whenever the button is clicked, the popup window is inflated and shown over the activity. Touching anywhere on the screen dismisses the popup window.

MainActivity.java

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void onButtonShowPopupWindowClick(View view) {

        // inflate the layout of the popup window
        LayoutInflater inflater = (LayoutInflater)
                getSystemService(LAYOUT_INFLATER_SERVICE);
        View popupView = inflater.inflate(R.layout.popup_window, null);

        // create the popup window
        int width = LinearLayout.LayoutParams.WRAP_CONTENT;
        int height = LinearLayout.LayoutParams.WRAP_CONTENT;
        boolean focusable = true; // lets taps outside the popup also dismiss it
        final PopupWindow popupWindow = new PopupWindow(popupView, width, height, focusable);

        // show the popup window
        // which view you pass in doesn't matter, it is only used for the window tolken
        popupWindow.showAtLocation(view, Gravity.CENTER, 0, 0);

        // dismiss the popup window when touched
        popupView.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                popupWindow.dismiss();
                return true;
            }
        });
    }
}

That’s it. You’re finished.

Going on

Check out how gravity values effect PopupWindow.

You can also add a shadow.

Further study

These were also helpful in learning how to make a popup window:

• PopupWindow documentation
• How To Create Pop Up Window In Android (YouTube video)
• Android Popup Window Example