Firebase 按下按钮时如何显示FutureBuilder对话框?
我用FutureBuilder上传图像FirebaseStorage,当我按下上传按钮时,我想显示一个等待对话框。在FireStorage上成功上载图像,但未显示任何内容。我的密码怎么了?我认为FutureBuilder返回小部件并按下按钮无效。也许这就是问题所在。或者我给FutureBuilder打错电话了。你对我的错误代码有什么建议吗 这是我的密码Firebase 按下按钮时如何显示FutureBuilder对话框?,firebase,dart,flutter,future,builder,Firebase,Dart,Flutter,Future,Builder,我用FutureBuilder上传图像FirebaseStorage,当我按下上传按钮时,我想显示一个等待对话框。在FireStorage上成功上载图像,但未显示任何内容。我的密码怎么了?我认为FutureBuilder返回小部件并按下按钮无效。也许这就是问题所在。或者我给FutureBuilder打错电话了。你对我的错误代码有什么建议吗 这是我的密码 Widget buildBody(BuildContext context) { return new Single
Widget buildBody(BuildContext context) {
return new SingleChildScrollView(
child: new Column(
children: [
new SizedBox(
width: double.infinity,
child: new RaisedButton(
child: new Text('Upload'),
onPressed: () {
futureBuilder();
},
),
),
],
),
);
}
Future mediaUpload() async {
final fileName = DateTime.now().millisecondsSinceEpoch.toString() + '.jpg';
final StorageReference storage = FirebaseStorage.instance.ref().child(fileName);
final StorageUploadTask task = storage.putFile(_image);
return task.future;
}
Widget futureBuilder() {
return new FutureBuilder(
future: mediaUpload(),
builder: (BuildContext context, AsyncSnapshot snapshot) {
switch (snapshot.connectionState) {
case ConnectionState.none:
print('ConnectionState.none');
return new Text('Press button to start.');
case ConnectionState.active:
print('ConnectionState.active');
return new Text('');
case ConnectionState.waiting:
waitingDialog(context);
return waitingDialog(context);
case ConnectionState.done:
print('ConnectionState.done');
if (snapshot.hasError) return new Text('Error: ${snapshot.error}');
print(snapshot.data.downloadUrl);
Navigator.of(context).pushReplacementNamed('home');
return new Text('Result: ${snapshot.data.downloadUrl}');
}
},
);
}
waitingDialog(BuildContext context) {
return showDialog(
context: context,
barrierDismissible: false,
builder: (BuildContext context) {
return new Center(
child: new SizedBox(
width: 40.0,
height: 40.0,
child: const CircularProgressIndicator(
value: null,
strokeWidth: 2.0,
),
),
);
},
);
}
我不能100%确定为什么
FutureBuilder
不起作用。但我有一个猜测。在上面的示例中,FutureBuilder
未连接到widgetTree(屏幕)。未附加表示从FutureBuilder
返回的值不显示在屏幕中。在这种情况下,文本
基于未连接到屏幕的快照.connectionState
返回
解决方法:(我已经测试过了,它成功了,你能验证一下吗)
谢谢你,迪内什,它很有魅力。但是如何使用FutureBuilder呢?我不明白。我将尝试找出
FutureBuilder
在这种情况下不起作用的原因。我查看了FutureBuilder
,但什么也没得到。我想我的猜测是正确的。如果我发现了什么,我会让你知道的。请做我想做的事情。如果我得到什么,我也会让你知道。有没有从future builder调用警报对话框的解决方案?
futureBuilder(BuildContext context) {
mediaUpload().then((task) { // fire the upload
Navigator.of(context).maybePop(); // remove the dialog on success upload
}); // we can use task(which returned from
// mediaUpload()) to get the values like downloadUrl.
waitingDialog(context); // show the spinner dialog
}