我正在使用文件选择器插件来选择图像 我想在屏幕上显示选择的图像 下面是我的代码 能够选择图像名称和路径并将它们显示为我的应用程序中的文本，但无法将它们显示为图像，在我显示这些图像后，我想将图像上传到 firebase 存储。
<小时 />import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:file_picker/file_picker.dart';
void main() => runApp(MyApp());
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => new _MyAppState();
}
class _MyAppState extends State<MyApp> {
final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
String _fileName;
String _path;
Map<String, String> _paths;
String _extension;
bool _loadingPath = false;
bool _multiPick = false;
FileType _pickingType = FileType.any;
TextEditingController _controller = new TextEditingController();
@override
void initState() {
super.initState();
_controller.addListener(() => _extension = _controller.text);
}
void _openFileExplorer() async {
setState(() => _loadingPath = true);
try {
if (_multiPick) {
_path = null;
_paths = await FilePicker.getMultiFilePath(
type: _pickingType,
allowedExtensions: (_extension?.isNotEmpty ?? false)
? _extension?.replaceAll(' ', '')?.split(',')
: null);
} else {
_paths = null;
_path = await FilePicker.getFilePath(
type: _pickingType,
allowedExtensions: (_extension?.isNotEmpty ?? false)
? _extension?.replaceAll(' ', '')?.split(',')
: null);
}
} on PlatformException catch (e) {
print("Unsupported operation" + e.toString());
}
if (!mounted) return;
setState(() {
_loadingPath = false;
_fileName = _path != null
? _path.split('/').last
: _paths != null ? _paths.keys.toString() : '...';
});
}
void _clearCachedFiles() {
FilePicker.clearTemporaryFiles().then((result) {
_scaffoldKey.currentState.showSnackBar(
SnackBar(
backgroundColor: result ? Colors.green : Colors.red,
content: Text((result
? 'Temporary files removed with success.'
: 'Failed to clean temporary files')),
),
);
});
}
@override
Widget build(BuildContext context) {
return new MaterialApp(
home: new Scaffold(
key: _scaffoldKey,
appBar: new AppBar(
title: const Text('File Picker example app'),
),
body: new Center(
child: new Padding(
padding: const EdgeInsets.only(left: 10.0, right: 10.0),
child: new SingleChildScrollView(
child: new Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new Padding(
padding: const EdgeInsets.only(top: 20.0),
child: new DropdownButton(
hint: new Text('LOAD PATH FROM'),
value: _pickingType,
items: <DropdownMenuItem>[
new DropdownMenuItem(
child: new Text('FROM AUDIO'),
value: FileType.audio,
),
new DropdownMenuItem(
child: new Text('FROM IMAGE'),
value: FileType.image,
),
new DropdownMenuItem(
child: new Text('FROM VIDEO'),
value: FileType.video,
),
new DropdownMenuItem(
child: new Text('FROM MEDIA'),
value: FileType.media,
),
new DropdownMenuItem(
child: new Text('FROM ANY'),
value: FileType.any,
),
new DropdownMenuItem(
child: new Text('CUSTOM FORMAT'),
value: FileType.custom,
),
],
onChanged: (value) => setState(() {
_pickingType = value;
if (_pickingType != FileType.custom) {
_controller.text = _extension = '';
}
})),
),
new ConstrainedBox(
constraints: BoxConstraints.tightFor(width: 100.0),
child: _pickingType == FileType.custom
? new TextFormField(
maxLength: 15,
autovalidate: true,
controller: _controller,
decoration:
InputDecoration(labelText: 'File extension'),
keyboardType: TextInputType.text,
textCapitalization: TextCapitalization.none,
)
: new Container(),
),
new ConstrainedBox(
constraints: BoxConstraints.tightFor(width: 200.0),
child: new SwitchListTile.adaptive(
title: new Text('Pick multiple files',
textAlign: TextAlign.right),
onChanged: (bool value) =>
setState(() => _multiPick = value),
value: _multiPick,
),
),
new Padding(
padding: const EdgeInsets.only(top: 50.0, bottom: 20.0),
child: Column(
children: <Widget>[
new RaisedButton(
onPressed: () => _openFileExplorer(),
child: new Text("Open file picker"),
),
new RaisedButton(
onPressed: () => _clearCachedFiles(),
child: new Text("Clear temporary files"),
),
],
),
),
new Builder(
builder: (BuildContext context) => _loadingPath
? Padding(
padding: const EdgeInsets.only(bottom: 10.0),
child: const CircularProgressIndicator())
: _path != null || _paths != null
? new Container(
padding: const EdgeInsets.only(bottom: 30.0),
height: MediaQuery.of(context).size.height * 0.50,
child: new Scrollbar(
child: new ListView.separated(
itemCount: _paths != null && _paths.isNotEmpty
? _paths.length
: 1,
itemBuilder: (BuildContext context, int index) {
final bool isMultiPath =
_paths != null && _paths.isNotEmpty;
final String name = 'File $index: ' +
(isMultiPath
? _paths.keys.toList()[index]
: _fileName ?? '...');
final path = isMultiPath
? _paths.values.toList()[index].toString()
: _path;
return new ListTile(
title: new Text(
name,
),
subtitle: new Text(_path),
);
},
separatorBuilder:
(BuildContext context, int index) =>
new Divider(),
)),
)
: new Container(),
),
],
),
),
)),
),
);
}
}
您可以像这样显示图像：
Image.file(
File(_path),
fit: BoxFit.cover,
width: double.infinity,
)
User Image.file 例如Image.file(File(_pickingType.path))
您可以使用 flutter 的image_picker包。 Pub.dev 包装
在生成方法上方定义文件。
File _image;
final picker = ImagePicker();
定义一个这样的函数，用于从库中选取图像：
Future getImage() async {
final pickedFile = await picker.getImage(source: ImageSource.gallery);
//File image = await ImagePicker.pickImage(source: ImageSource.gallery);
setState(() {
if (pickedFile != null) {
_image = File(pickedFile.path);
} else {
print('No image selected');
}
});
}
然后从按钮的某个onPress方法访问该getImage((。 您可以简单地通过此小部件显示图像：
Image.file(_image),
File _selected_file = file_you_got_from_exporer;
FileImage(_selected_file)
Image.memory(_pickedFile.toUint8List())