firebase - FirebaseStorage抖动

Question

我是Firebase的新手，我无法弄清楚我应该将什么样的参数传递给putfile中的
以下代码，是否有任何有关flutter的Firebase的教程或适当的文档？

实现代码

import "dart:io";
import "package:flutter/material.dart";
import "package:firebase_storage/firebase_storage.dart";
import "package:flutter/widgets.dart";

class uploadApp extends StatefulWidget{
  @override
  State<StatefulWidget> createState() =>_uploadApp(); 
}

class _uploadApp extends State<uploadApp>{

  var count=1;
  final File file = File("images/ts2.jpg");
  final FirebaseStorage _storage = FirebaseStorage(storageBucket:"gs://console.firebase.google.com/project/baby-name-4ef54/storage/baby-name-4ef54.appspot.com");
  StorageUploadTask _uploadTask;

  void firebasebackend(){
    String filePath = "images/$count.jpg";
    setState(() {
      _uploadTask = _storage.ref().child(filePath).putFile(file);
    });
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title:"upload",
      home:Material(
        child:Container(child:Center(
          child:
           Column(
            children: <Widget>[
              Container(
                width: 300.0,
                height: 300.0,
                decoration: BoxDecoration(
                  borderRadius: BorderRadius.all(Radius.circular(300.0)),
                  image:DecorationImage(
                    image: AssetImage("images/ts2.jpg"),
                    fit: BoxFit.cover
                  )
                ),
              ),
              Center(
                child: RaisedButton(
                  child:Text("Upload"),
                  onPressed: (){
                    firebasebackend();
                    setState(){
                  count=count+1;
                       };     
                  },
                ),
              )
            ],
          ),
        )
      )
      )
    );
  }
}

'package:firebase_storage/src/storage_reference.dart': Failed assertion: line 62 pos 12: 'file.existsSync()': is not true.

将图片直接从文件夹直接上传到Firebase存储，该怎么办？

Answer 1

根据firebase_storage插件的代码:

  /// Asynchronously uploads a file to the currently specified
  /// [StorageReference], with an optional [metadata].
  StorageUploadTask putFile(File file, [StorageMetadata metadata]) {
    assert(file.existsSync());
    final _StorageFileUploadTask task =
        _StorageFileUploadTask._(file, _firebaseStorage, this, metadata);
    task._start();
    return task;
  }

将file作为参数，并将类型StorageMetadata的变量作为可选参数。

https://github.com/FirebaseExtended/flutterfire/blob/master/packages/firebase_storage/lib/src/storage_reference.dart#L61

https://api.dart.dev/stable/2.7.0/dart-io/File-class.html