Android: call a method after a textView is changed

Question

a simple issue here, but one I haven't been able to find a simple solution for. My Android app has a button that calls a calculations-heavy method which may take a while to return results. I want the user to know that the app is working, not frozen, so upon hitting that button I want to display a textView with a loading message, then call the method and load its results to another textView (while also hiding the first one). How can I make sure the method is started only AFTER the loading message becomes visible, because the code below fires the method when it's still not visible?

        buttonCalculate.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                loadingMessage.setVisibility(View.VISIBLE);
                findSolution();
            }
        });

Answer 1

you are looking for a Progress Bar, it's a an android feature that android made for you. Here is a link for the official google site: https://developer.android.com/reference/android/widget/ProgressBar