Is there a way of retrieving a TextView's visible line count or range?

Question

I have a full-screen TextView holding a long Spanned that requires scrolling. The TextView's getLineCount() gives me the total number of lines used for the entire block of text but I'd like to know how many lines of text are currently visible on the screen.

Or, better yet, is there a way to figure out the range of lines currently visible on the screen? For example, as the view scrolls, can I tell that lines 20-60 are currently visible?

Robert Nekic · Accepted Answer · 2010-02-10T21:28:03.307

37

I figured out the answer:

int height    = myTextView.getHeight();
int scrollY   = myTextView.getScrollY();
Layout layout = myTextView.getLayout();

int firstVisibleLineNumber = layout.getLineForVertical(scrollY);
int lastVisibleLineNumber  = layout.getLineForVertical(scrollY+height);

edited Feb 10 '10 at 21:28

answered Feb 10 '10 at 20:08

Robert Nekic

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1

@MrSuS it returns null if you want to retrieve it before View was laid out. – Yaroslav Mytkalyk Jan 31 '14 at 14:46
2

I tried using the above mentioned code but it returns wrong line count when using in the landscape orientation. Also few partial lines get visible. – user2538359 May 12 '14 at 10:50
for me to getting getLayout() returns null – vijay Jul 05 '16 at 11:47
getScrollY always returns 0 for me. – Sver Sep 17 '17 at 23:31
1

Doesn't work for me returns the index of the last line (I checked by counting), maybe because of padding or something. – Nimitz14 Dec 17 '18 at 18:02

score 6 · Answer 2 · answered Feb 27 '14 at 18:27

To make them work you should write the code posted by @Robert in this way:

ViewTreeObserver vto = txtViewEx.getViewTreeObserver();
        vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                ViewTreeObserver obs = txtViewEx.getViewTreeObserver();
                obs.removeOnGlobalLayoutListener(this);
                height = txtViewEx.getHeight();
                scrollY = txtViewEx.getScrollY();
                Layout layout = txtViewEx.getLayout();

                firstVisibleLineNumber = layout.getLineForVertical(scrollY);
                lastVisibleLineNumber = layout.getLineForVertical(height+scrollY);

            }
        });

Is there a way of retrieving a TextView's visible line count or range?

2 Answers2

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