How to get number of lines of TextView?

I want to get the number of lines of a text view

textView.setText("Test line 1 Test line 2 Test line 3 Test line 4 Test line 5.............")

textView.getLineCount(); always returns zero

Then I have also tried:

ViewTreeObserver vto = this.textView.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {

    @Override
    public void onGlobalLayout() {
        ViewTreeObserver obs = textView.getViewTreeObserver();
        obs.removeGlobalOnLayoutListener(this);
        System.out.println(": " + textView.getLineCount());

    }
});

It returns the exact output.

But this works only for a static layout.

When I am inflating the layout dynamically this doesn't work anymore.

How could I find the number of line in a TextView?

Solution 1:

I was able to get getLineCount() to not return 0 using a post, like this:

textview.setText(“Some text”);
textview.post(new Runnable() {
    @Override
    public void run() {
        int lineCount = textview.getLineCount();
        // Use lineCount here
    }
});

Solution 2:

As mentioned in this post,

getLineCount() will give you the correct number of lines only after a layout pass.

It means that you need to render the TextView first before invoking the getLineCount() method.

Solution 3:

ViewTreeObserver is not so reliable especially when using dynamic layouts such as ListView.

Let's assume:
1. You will do some work depending on the lines of TextView.
2. The work is not very urgent and can be done later.

Here is my solution:

public class LayoutedTextView extends TextView {

        public LayoutedTextView(Context context) {
                super(context);
        }

        public LayoutedTextView(Context context, AttributeSet attrs) {
                super(context, attrs);
        }

        public LayoutedTextView(Context context, AttributeSet attrs, int defStyle) {
                super(context, attrs, defStyle);
        }

        public interface OnLayoutListener {
                void onLayouted(TextView view);
        }

        private OnLayoutListener mOnLayoutListener;

        public void setOnLayoutListener(OnLayoutListener listener) {
                mOnLayoutListener = listener;
        }

        @Override
        protected void onLayout(boolean changed, int left, int top, int right,
                        int bottom) {
                super.onLayout(changed, left, top, right, bottom);

                if (mOnLayoutListener != null) {
                        mOnLayoutListener.onLayouted(this);
                }
        }

}

Usage:

LayoutedTextView tv = new LayoutedTextView(context);
tv.setOnLayoutListener(new OnLayoutListener() {
        @Override
        public void onLayouted(TextView view) {
                int lineCount = view.getLineCount();
                // do your work
        }
});

Solution 4:

 textView.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {

        @Override
        public boolean onPreDraw() {
            // Remove listener because we don't want this called before _every_ frame
            textView.getViewTreeObserver().removeOnPreDrawListener(this)

            // Drawing happens after layout so we can assume getLineCount() returns the correct value
            if(textView.getLineCount() > 2) {
                // Do whatever you want in case text view has more than 2 lines
            }  

            return true; // true because we don't want to skip this frame
        }
});

Solution 5:

I think the crux of this question is that people want to be able to find out the size of a TextView in advance so that they can dynamically resize it to nicely fit the text. A typical use might be to create talk bubbles (at least that was what I was working on).

I tried several solutions, including use of getTextBounds() and measureText() as discussed here. Unfortunately, both methods are slightly inexact and have no way to account for line breaks and unused linespace. So, I gave up on that approach.

That leaves getLineCount(), whose problem is that you have to "render" the text before getLineCount() will give you the number of lines, which makes it a chicken-and-egg situation. I read various solutions involving listeners and layouts, but just couldn't believe that there wasn't something simpler.

After fiddling for two days, I finally found what I was looking for (at least it works for me). It all comes down to what it means to "render" the text. It doesn't mean that the text has to appear onscreen, only that it has to be prepared for display internally. This happens whenever a call is made directly to invalidate() or indirectly as when you do a setText() on your TextView, which calls invalidate() for you since the view has changed appearance.

Anyway, here's the key code (assume you already know the talk bubble's lineWidth and lineHeight of a single line based on the font):

TextView talkBubble;
// No peeking while we set the bubble up.
talkBubble.setVisibility( View.INVISIBLE );
// I use FrameLayouts so my talk bubbles can overlap
// lineHeight is just a filler at this point
talkBubble.setLayoutParams( new FrameLayout.LayoutParams( lineWidth, lineHeight ) );
// setText() calls invalidate(), which makes getLineCount() do the right thing.
talkBubble.setText( "This is the string we want to dynamically deal with." );
int lineCount = getLineCount();
// Now we set the real size of the talkBubble.
talkBubble.setLayoutParams( new FrameLayout.LayoutParams( lineWidth, lineCount * lineHeight ) );
talkBubble.setVisibility( View.VISIBLE );

Anyway, that's it. The next redraw will give a bubble tailor-made for your text.

Note: In the actual program, I use a separate bubble for determining lines of text so that I can resize my real bubble dynamically both in terms of length and width. This allows me to shrink my bubbles left-to-right for short statements, etc.

Enjoy!