My button\'s layout_width set to match_parent.
In order to display multi lines on the button, I tried:
insert \'\\n\' into the text on button
In case you want to do that programmaticaly you can use System.getProperty("line.separator") in the string to change lines. Like this:
System.getProperty("line.separator")
String mybuttontext=line1+System.getProperty("line.separator")+line2;
and then set this String as buttons text.