设置Theme为Theme.Dialog形式的Activity的宽和高

mDisplay = getWindowManager().getDefaultDisplay();
DisplayMetrics outMetrics = new DisplayMetrics();
mDisplay.getMetrics(outMetrics);
LayoutParams layoutParams = getWindow().getAttributes();
layoutParams.width = (int) (outMetrics.widthPixels * 0.7);
layoutParams.height = (int) (outMetrics.heightPixels * 0.8);
getWindow().setAttributes(layoutParams);