android - Ellipsize not working properly for a multiline TextView with an arbitrary maximum height

Question

I have a TextView with an unknown maximum height, which is dependent on the device's DPI/screen resolution. So, for instance, on and MDPI device this maximum height makes it possible to show only 2 lines at a time, a value that can be increased up to an undefined number.

My issue is related with the ellipsize functionality. Let's suppose that a certain device allows for 4 lines to be displayed. If I manually set the maximum number of lines, like this...

<TextView
    android:id="@+id/some_id"
    android:layout_width="fill_parent"
    android:layout_height="0dip"
    android:ellipsize="end" 
    android:maxLines="4"
    android:singleLine="false"
    android:layout_weight="1"
    android:gravity="center_vertical"
    android:text="This is some really really really really really long text"
    android:textSize="15sp" />

...everything works OK. If the text doesn't fit properly, then the ellipsis are added at the end of the fourth line, like this:

This is some
really really
really really
really long...

But I'd rather not set the number of lines as a static variable, as I would prefer to include support for any combination of DPI/screen resolution. So if I remove maxLines the ellipsis is no longer correctly shown at line four, showing instead an incomplete portion of text:

This is some
really really
really really
really long

If I slightly increase the TextView size, I can see that the rest of the text is still being drawn "behind" the other Views. Setting the variable maxHeight doesn't seem to work either.

I really can't seem to find a solution for this issue. Any ideas? If it helps, I'm working only with Android v4.0.3 and up (API level 15).

Answer 1

Calculate how many lines fit into the TextView with TextView#getHeight() and TextView#getLineHeight(). Then call TextView#setMaxLines().

ViewTreeObserver observer = textView.getViewTreeObserver();
observer.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
    @Override
    public void onGlobalLayout() {
        int maxLines = (int) textView.getHeight()
                / textView.getLineHeight();
        textView.setMaxLines(maxLines);
        textView.getViewTreeObserver().removeGlobalOnLayoutListener(
                this);
    }
});