mainTabHome是我的控件radioButton
Drawable[] drawables = null;
drawables = mainTabHome.getCompoundDrawables();
//int left, int top, int right, int bottom
drawables[1].setBounds(0, 0, 45, 45);
mainTabHome.setCompoundDrawables(drawables[0], drawables[1],
drawables[2], drawables[3]);
这样就可以设置drawableXxx里面图片大小了