How to get number of lines of TextView?

Question

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.............\")

Answer 1

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.

Answer 2

Are you doing this onCreate? The Views aren't laid out yet, so getLineCount() is 0 for a while. If you do this later in the Window LifeCycle, you'll get your line count. You'll have a hard time doing it onCreate, but onWindowFocusChanged with hasFocus=true usually has the Views measured by now.

The textView.post() suggestion is also a good one

Answer 3

 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
        }
});

Answer 4

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
        }
});