flutter标题栏滑动隐藏显示

flutter标题栏滑动隐藏显示

1.  
   ScrollController _scrollController = ScrollController();
2.  
   int _titleAlpha = 0; //范围 0-255

使用 ScrollController 来监听滚动事件，在initState()方法中增加监听

1.  
   _scrollController
2.  
   ..addListener(() {
3.  
   setState(() {
4.  
   if (_scrollController.offset > titleHeight) {
5.  
   _titleAlpha = 255;
6.  
   } else if (_scrollController.offset <= 0) {
7.  
   _titleAlpha = 0;
8.  
   } else {
9.  
   _titleAlpha = _scrollController.offset * 255 ~/ titleHeight;
10.  
    }
11.  
    });
12.  
    });

最后设置颜色为Colors.white.withAlpha(_titleAlpha)