如何将FutureBuilder<File>图像转换为BoxDecoraiton图像
如何将FutureBuilder<File>图像转换为BoxDecoraiton图像
提问于 2018-06-06 06:47:51
使用flutter插件image_picker 0.4.4，我可以使用以下内容显示相机或图库中的图像
Widget _previewImageBkg() {
return FutureBuilder<File>(
future: _imageFileBkg,
builder: (BuildContext context, AsyncSnapshot<File> snapshot) {
if (snapshot.connectionState == ConnectionState.done && snapshot.data != null) {
print('_previewImage.........check callback for this image. .>>>>>');
final File file = snapshot.data;
myBgURL = uploadFile('user@image.com_B.jpg', file);
return Image.file(snapshot.data);
} else if (snapshot.error != null) {
return const Text(
'Error picking image.',
textAlign: TextAlign.center,
);
} else {
return const Text(
'You have not yet picked an image.',
textAlign: TextAlign.center,
);
}
}
)如果将图像放入容器中，则图像显示正常
return Scaffold(
appBar: AppBar(
title: Text('Set Profile Images'),
),
body: Center(
child: new Container(
width: screen.width,
height: 250.0,
child: _previewImageBkg()),
),但是，我想将其显示在图像中(BoxDecoration：...)
child: new Container(
width: screenSize.width,
height: 275.0,
decoration: new BoxDecoration(
image: new DecorationImage(
image: (_previewImageBkg()== null ? new ExactAssetImage('images/nav_header_bg.png') : _previewImageBkg()),
fit: BoxFit.cover,
),
),
),
/flutter (29415): type 'FutureBuilder<File>' is not a subtype of type 'ImageProvider<dynamic>'如何将此文件转换为Image？更大的目标是获得BoxDecoration的- fit: BoxFit.cover -属性。
回答 1
Stack Overflow用户
回答已采纳
发布于 2018-06-06 10:20:22
像这样使用FileImage来构建你的装饰容器--关联的Future必须返回一个文件：
@override
Widget build(BuildContext context) {
return new FutureBuilder<File>(
future: _imageFileBkg,
builder: (context, snapshot) {
if (!snapshot.hasData) return Container(); // or some other placeholder
return new Container(
width: screenSize.width,
height: 275.0,
decoration: new BoxDecoration(
image: new DecorationImage(
image: new FileImage(snapshot.data),
fit: BoxFit.cover,
)),
);
},
);
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/50709969
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