Question

I have a custom View, which consists of a button, and a view that animates in below the button that contains a custom view of multi-choice items. When the user presses the button, I show the “dropdown” with the items. I want to hide the “dropdown” when they press outside of the dropdown. I tried overriding the onTouchEvent and the onInterceptTouchEvent, but these aren’t always called.

I took a look at the source for the Spinner, and noticed that Google is using an Dialog for what I believe to be its dropdown (how it is being positioned is beyond me at this point).

Is there any way I can have my View intercept ALL touch events on the Window?

Answer 1

You can implement the onTouchListener on the top ViewGroup (e.g., on a LinearLayout or whatever you’re using).

Then, determine the position of your custom view: If the touch position (using event.getX() and event.getY() methods) is outside the View (using myView.getTop(), etc.), then it can hide it (myView.setVisibility(View.GONE).

In any case, it should return false to allow the children Views to handle the touch.

From the android dev guide:

Remember that key events are always delivered to the View currently in focus. They are dispatched starting from the top of the View hierarchy, and then down, until they reach the appropriate destination.

Note: Android will call event handlers first and then the appropriate default handlers from the class definition second. As such, returning true from these event listeners will stop the propagation of the event to other event listeners and will also block the callback to the default event handler in the View. So be certain that you want to terminate the event when you return true.