RenderAspectRatio 具有无限约束

Question

我正在尝试使用此代码在颤振应用程序中构建滚动滑块来构建约束：

var cardAspectRatio = 12.0 / 16.0;
var widgetAspectRatio = cardAspectRatio * 1.2;

AspectRatio (
aspectRatio: widgetAspectRatio,
  child: LayoutBuilder(builder: (context, constraints) {
    var width = constraints.maxWidth;
    var height = constraints.maxHeight;
})

为了给它它的宽度和高度约束，但由此产生的错误表明框约束是无界的：

I/flutter ( 6957): RenderAspectRatio has unbounded constraints.
I/flutter ( 6957): This RenderAspectRatio was given an aspect ratio of 
                   0.8999999999999999 but was given both unbounded
I/flutter ( 6957): constraints: BoxConstraints(unconstrained)
I/flutter ( 6957): size: MISSING
I/flutter ( 6957): aspectRatio: 0.9

我该如何解决这个问题？

Answer 1

I had the same problem, I realized the error code gives me the solution, put the AspectRatio inside a container widget and specify its width and height. In your case, the code below will work out

Container(
    width = your width;
    height = your height;
    child:AspectRatio (
        aspectRatio: widgetAspectRatio,
        child: LayoutBuilder(builder: (context, constraints) {
            var width = constraints.maxWidth;
            var height = constraints.maxHeight;
        }
    )
)