代码设置按钮样式的方法

StateListDrawable states = new StateListDrawable();
states.addState(new int[] {android.R.attr.state_pressed},
    getResources().getDrawable(R.drawable.pressed));
states.addState(new int[] {android.R.attr.state_focused},
    getResources().getDrawable(R.drawable.focused));
states.addState(new int[] { },
    getResources().getDrawable(R.drawable.normal));
imageButton.setImageDrawable(states);