Question

我正在做一个颤振课程，这是我的相关代码：

Container(
                  color: kBottomContainerColour,
                  margin: EdgeInsets.only(top: 10.0),
                  width: double.infinity,
                  height: kBottomContainerHeight,
                ),

我一直得到这个：

These invalid constraints were provided to _RenderColoredBox's layout() function by the following function, which probably computed the invalid constraints in question:
  RenderConstrainedBox.performLayout (package:flutter/src/rendering/proxy_box.dart:268:14)
The offending constraints were: BoxConstraints(w=Infinity, h=80.0)
The relevant error-causing widget was: 
  Container file:///F:/Works/Projects/flutter/Flutter-Course-Resources/bmi-calculator-flutter1/lib/input_page.dart:241:24

虽然它在课程中运行良好请帮忙

Answer 1

代替 width: double.infinity，

使用，

width: MediaQuery.of(context).size.width

Answer 2

不要使用double.infinity。使用 MediaQuery 从当前小部件上下文中获取大小，并从中获取宽度。在这种情况下，请执行以下操作：

Container(color: kBottomContainerColour,
                  margin: EdgeInsets.only(top: 10.0),
                  width: MediaQuery.of(context).size.width
                  height: kBottomContainerHeight,
                ),

请注意，每次使用 MediaQuery 时，小部件都会重新加载其状态。因此，请务必分解您的小部件，并遵循 google 的性能指南：

https://flutter.dev/docs/perf/rendering/best-practices

颤动：无限宽度

2 个答案: