How to use textview.getLayout()? It returns null
I’m trying set a layout for textview
so I can use getEllipsisCount()
method. But below code returns null as layout value.
How can I take layout and then use getEllipsisCount(0)
method.
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView mytextview =(TextView) findViewById(R.id.textView1);
mytextview.setText(myText);
Layout layout = mytextview.getLayout();
if(layout != null){
mytextview.setText("very good layout worked\n");
}
}
}
You are calling it too early, thats why it is returning null
Try this
ViewTreeObserver vto = mytextview.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
Layout layout = mytextview.getLayout();
}
});
From the documentation:
public final Layout getLayout ()
Added in API level 1 Returns the Layout that is currently being used to display the text. This can be null if the text or width has recently changes.
So probably your text has changes or you call it too early.
Look at this answer where is stated
This only works after the layout phase, otherwise the returned layout will be null, so call this at an appropriate place in your code.
Call
TextView.onPreDraw();
It creates the layout.
I recently encountered this problem myself. For any newcomers to this thread, the accepted answer by @Pragnani along with the comment from @dimsuz provides a nice and compact solution. Adding an OnPreDrawListener
to the view tree of the text view, wait for a reference to a layout and use it, and lastly remove the listener after any work requiring the layout is finished.
Given the example code from OP, implementing the solution could look something like this:
public class MainActivity extends Activity implements ViewTreeObserver.OnPreDrawListener {
// maintain a reference to the view so we can later remove the listener
private TextView mytextview;
@Override
public boolean onPreDraw() {
Layout layout = mytextview.getLayout();
if (layout != null) {
// use layout here...
int n = layout.getEllipsisCount(0);
// work requiring a layout is finished; remove listener from view
mytextview.getViewTreeObserver().removeOnPreDrawListener(this);
}
return true;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mytextview = (TextView) findViewById(R.id.textView1);
// add listener to the view
mytextView.getViewTreeObserver().addOnPreDrawListener(this);
}
}