Question

我是Flutter的新手，我喜欢它，但是我对建筑物的布局并不满意。

我正在编写一个包含Cards ListView的应用程序。每张卡都在一个容器内，并包含一张图像（高度和宽度固定）和一个文本。

我无法正确处理卡内的图像。我希望图像能覆盖盒子的宽度。谢谢。

这是代码：

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final title = 'MyApp';

    return MaterialApp(
      title: title,
      home: Scaffold(
        appBar: AppBar(
          title: Text(title),
        ),
        body: ListView(
          children: <Widget>[
              Container(
                    margin:EdgeInsets.all(8.0),
                    child: Card(
                        shape: RoundedRectangleBorder(borderRadius: BorderRadius.all(Radius.circular(8.0))),
                        child: InkWell(
                           onTap: () => print("ciao"),     
                           child: Column(
                                children: <Widget>[
                                    ClipRRect(
                                      borderRadius: BorderRadius.only(
                                        topLeft: Radius.circular(8.0),
                                        topRight: Radius.circular(8.0),
                                      ),
                                      child: Image.asset(
                                        'img/britannia.jpg',
                                        width: 300,
                                        height: 150,
                                        fit:BoxFit.fill  

                                      ),
                                    ),
                                    ListTile(
                                      title: Text('Pub 1'),
                                      subtitle: Text('Location 1'),
                                    ),
                                ],
                           ),
                        ),
                    ),
              ),
          ],
        ),
      ),
    );
  }
}

Answer 1

这对我有用

Image.network(imageUrl, fit: BoxFit.fitWidth,),

Answer 2

我不知道如何。但这确实可以将固定大小的图像保存在容器中只需在容器中添加对齐方式

    Container(
      height: double.infinity,
      alignment: Alignment.center, // This is needed
      child: Image.asset(
        Constants.ASSETS_IMAGES + "logo.png",
        fit: BoxFit.contain,
        width: 300,
      ),
    );

Answer 3

 Image.asset(
                  'assets/images/desert.jpg',
                  height: 150,
                  width: MediaQuery.of(context).size.width,
                  fit:BoxFit.cover

              )

Answer 4

您需要在crossAxisAlignment: CrossAxisAlignment.stretch,中添加-Column，以便孩子可以占用水平空间。

工作代码：

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final title = 'MyApp';

return MaterialApp(
  title: title,
  home: Scaffold(
    appBar: AppBar(
      title: Text(title),
    ),
    body: ListView(
      children: <Widget>[
        Container(
          margin:EdgeInsets.all(8.0),
          child: Card(
            shape: RoundedRectangleBorder(borderRadius: BorderRadius.all(Radius.circular(8.0))),
            child: InkWell(
              onTap: () => print("ciao"),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,  // add this
                children: <Widget>[
                  ClipRRect(
                    borderRadius: BorderRadius.only(
                      topLeft: Radius.circular(8.0),
                      topRight: Radius.circular(8.0),
                    ),
                    child: Image.network(
                        'https://placeimg.com/640/480/any',
                       // width: 300,
                        height: 150,
                        fit:BoxFit.fill

                    ),
                  ),
                  ListTile(
                    title: Text('Pub 1'),
                    subtitle: Text('Location 1'),
                  ),
                ],
              ),
            ),
          ),
        ),
        Container(
          margin:EdgeInsets.all(8.0),
          child: Card(
            shape: RoundedRectangleBorder(borderRadius: BorderRadius.all(Radius.circular(8.0))),
            child: InkWell(
              onTap: () => print("ciao"),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: <Widget>[
                  ClipRRect(
                    borderRadius: BorderRadius.only(
                      topLeft: Radius.circular(8.0),
                      topRight: Radius.circular(8.0),
                    ),
                    child: Image.network(
                        'https://placeimg.com/640/480/any',
                        // width: 300,
                        height: 150,
                        fit:BoxFit.fill

                    ),
                  ),
                  ListTile(
                    title: Text('Pub 1'),
                    subtitle: Text('Location 1'),
                  ),
                ],
              ),
            ),
          ),
        ),
        Container(
          margin:EdgeInsets.all(8.0),
          child: Card(
            shape: RoundedRectangleBorder(borderRadius: BorderRadius.all(Radius.circular(8.0))),
            child: InkWell(
              onTap: () => print("ciao"),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: <Widget>[
                  ClipRRect(
                    borderRadius: BorderRadius.only(
                      topLeft: Radius.circular(8.0),
                      topRight: Radius.circular(8.0),
                    ),
                    child: Image.network(
                        'https://placeimg.com/640/480/any',
                        // width: 300,
                        height: 150,
                        fit:BoxFit.fill

                    ),
                  ),
                  ListTile(
                    title: Text('Pub 1'),
                    subtitle: Text('Location 1'),
                  ),
                ],
              ),
            ),
          ),
        ),
      ],
    ),
      ),
    );
  }
}

输出：

Answer 5

将图像小部件放在容器内，并为容器提供对齐中心，并为图像提供特定的宽高。

return Container(
      alignment: Alignment.center,// use aligment
      color: Color.fromRGBO(0, 96, 91, 1.0),
      child: Image.asset('assets/images/splash_logo.png',
        height: 150,
        width: 150,
      fit: BoxFit.cover),
    );

Answer 6

我用了这个并且与我一起工作得很好！

  Container(
                    width: MediaQuery.of(context).size.width,
                    height: 175,
                    decoration: BoxDecoration(
                      image: DecorationImage(
                        fit: BoxFit.cover,
                        image: NetworkImage(YOUTUBE_THUMBNAIL_PART_ONE +
                            video.key +
                            YOUTUBE_THUMBNAIL_PART_TWO),
                      ),
                    )),

Answer 7

您想要做的可能是使用较大容器的大小。在这种情况下，您的媒体应该占据整个专用空间：

return Container(
      alignment: Alignment.center,
      height: double.infinity,
      width: double.infinity,
      child: Image.asset(
        '', //TODO fill path
        height: double.infinity,
        width: double.infinity,
        fit: BoxFit.cover,
      ),
    );

您可以使用fit值：

BoxFit.cover将覆盖整个容器
BoxFit.fitWidth将适合宽度，并最终放置水平白条以填充空间
BoxFit.fitHeight将适合高度，并最终放置垂直白条以填充空间

Answer 8

如果可以使用fit属性，那么我将这个非常清晰的备忘单（章节fit属性）详细说明所有内容：https://medium.com/jlouage/flutter-boxdecoration-cheat-sheet-72cedaa1ba20

Answer 9

我遇到了同样的问题，我只是在使用MediaQuery类获取屏幕宽度后，在Image.asset类中添加了fit：BoxFit.fill **

    Container(
              child:Image.asset(link,fit: BoxFit.fill,)
              width: screensize.width,
              height: 150,
            ))

Answer 10

您只需要 fit 类的 Image 属性：

Image.asset(
  'your_image_asset',
  fit: BoxFit.fill, // Expands to fill parent (changes aspect ratio)
)

或

Image.asset(
  'your_image_asset',
  fit: BoxFit.cover, // Zooms the image (maintains aspect ratio)
)

Answer 11

            Center(
          child: Container(
            margin: EdgeInsets.only(top: 75),
            width: 120,
            height: 120,
            alignment: Alignment.center,
            child: Image.asset(
              "assets/images/call.png",
              fit: BoxFit.cover,
              height: 45,
              width: 45,
            ),
            decoration: new BoxDecoration(
              color: Colors.white,
              borderRadius: new BorderRadius.all(new Radius.circular(120)),
              border: new Border.all(
                color: Colors.blue,
                width: 4.0,
              ),
            ),
          ),
        )

使用您想要的边框

# training loop
w0 = -1
w1 = 1
b = 1
a = 0.5
epochs = 50000
for i in range(epochs):
  # loop over all the points to calculate the gradient
  dw0 = 0
  dw1 = 0
  db = 0

  for point in data:

    x0 = point[0]
    x1 = point[1]
    y = point[-1]

    z = (w0 * x0) + (w1 * x1) + b
    # print(z)
    a = 1/(1 + np.exp(-z))  # sigmoid
    # print(a)

    dz = a - y  # dz = dL/dz (derivative of loss function wrt z)

    dw0 += dz * x0
    dw1 += dz * x1
    db += dz

  dw0 /= len(data)  # av. val over all data points
  dw1 /= len(data)
  db /= len(data)

    
  # gradient descent step
  w0 = w0 - (a * dw0)
  w1 = w1 - (a * dw1)
  b  =  b - (a * db) 

print(w0, w1, b)
print()

Flutter如何处理固定尺寸的盒子内的图像？

11 个答案: