CODEWITHSUNDEEP
android-studiovisibilityandroid-scrollviewvisible
tbear
tbear

Reputation: 135

Scroll after view becomes visible

I am trying to scroll to the bottom of my scrollView after a view becomes visible with button click. The problem is the scrollTo function is applied before the view is actually visible. I know this because when the button is pressed twice, it scrolls to the bottom on the second click. So, is there a way to scroll after the view becomes visible?

button.setOnClickListener(v -> {
    constraintLayout.setVisibility(View.VISIBLE);
    scrollView.smoothScrollTo(0, constraintLayout.getBottom());
}

Upvotes: 1

Views: 712

Answers (2)

Crabster
Crabster

Reputation: 16

Another option is to use a listener.

ViewTreeObserver.OnPreDrawListener viewVisibilityChanged = new ViewTreeObserver.OnPreDrawListener() {
    @Override
    public boolean onPreDraw() {
        if (my_view.getVisibility() == View.VISIBLE) {
            scroll_view.smoothScrollTo(0, scroll_view.getHeight());
        }
        return true;
    }
};

You can add it to your view this way :

my_view.getViewTreeObserver().addOnPreDrawListener(viewVisibilityChanged);

Upvotes: 0

tbear
tbear

Reputation: 135

button.setOnClickListener(v -> {
    constraintLayout.setVisibility(View.VISIBLE);
    Handler handler = new Handler();
    handler.postDelayed(() -> {
        scrollView.smoothScrollTo(0, constraintLayout.getBottom());
    }, 100);
}

I just figured out this works, but I was hoping to not use a delay.

Upvotes: 1

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