Android的requestLayout无效

public void requestLayout() {

super.requestLayout();

    post(measureAndLayout);

}

private final RunnablemeasureAndLayout =new Runnable() {

@Override

    public void run() {

measure(

MeasureSpec.makeMeasureSpec(getWidth(), MeasureSpec.EXACTLY),

                MeasureSpec.makeMeasureSpec(getHeight(), MeasureSpec.EXACTLY));

        layout(getLeft(), getTop(), getRight(), getBottom());

    }

};

使用自己定义的requestLayout。