quit.show();
WindowManager.LayoutParams params0 = quit.getWindow().getAttributes();
params0.width = (int) (scrrenW*0.9);
params0.height = (int) (screenH*0.25);
quit.getWindow().setAttributes(params0);
quit是个dialog;
screenW是屏幕宽度;
原文：http://www.cnblogs.com/liauau/p/4662499.html