我做了一个自定义视图.如果将视图添加到布局XML文件并将高度设置为fill_parent“ specSize”,则返回0.为什么？

码：

    @Override
protected void onMeasure(int widthMeasureSpec,int heightMeasureSpec) {
        int measuredHeight = 90;

        int specMode = MeasureSpec.getMode(heightMeasureSpec);
        int specSize = MeasureSpec.getSize(MeasureSpec.getMode(heightMeasureSpec));

        if(specMode != MeasureSpec.UNSPECIFIED){
         measuredHeight = specSize;
        }
        setMeasuredDimension(60,measuredHeight);
}

有人知道我如何获得fill_parent的高度吗？