flutter - 在颤动中调用另一个函数飞镖进入页面

Question

我有一个带有应用栏标题的空白页面和一个称为上传页面的功能飞镖。如何将此函数调用到页面？如何显示带有上传功能的页面？

另一个问题是，flutter 可以调用一个按钮来从文件资源管理器中选择文件。单击按钮后，它将导航到文件目录，以便我可以将文件上传到页面，页面将显示我上传的文件。

[空白页][2]

上传页面.dart

import 'package:file_picker/file_picker.dart';
import 'package:flutter/services.dart';
import 'package:flutter_auth/Screens/Login/components/body.dart';

main() => runApp(UploadPage());

class UploadPage extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return _App();
  }
}

class _App extends State<UploadPage> {
  String _fileName;
  String _path;
  Map<String, String> _paths;
  String _extension;
  bool _loadingPath = false;
  bool _multiPick = false;
  bool _hasValidMime = false;
  FileType _pickingType;
  TextEditingController _controller = new TextEditingController();

  @override
  void initState() {
    super.initState();
    _controller.addListener(() => _extension = _controller.text);
  }

  void _openFileExplorer() async {
    if (_pickingType != FileType.custom || _hasValidMime) {
      setState(() => _loadingPath = true);
      try {
        if (_multiPick) {
          _path = null;
          _paths = await FilePicker.getMultiFilePath(
              type: _pickingType, allowedExtensions: [_extension]);
        } else {
          _paths = null;
          _paths = await FilePicker.getMultiFilePath(
              type: _pickingType, allowedExtensions: [_extension]);
        }
      } 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()
                : '...';
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text("FilePickerApp"),
        ),
        body: Container(
          child: Center(
              child: Column(
            children: <Widget>[
              new Padding(
                padding: const EdgeInsets.only(top: 50.0, bottom: 20.0),
                child: new RaisedButton(
                  onPressed: () => _openFileExplorer(),
                  child: new Text("Open file picker"),
                ),
              ),
              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(),
              ),
            ],
          )),
        ),
      ),
    );
  }
}


  [1]: https://i.stack.imgur.com/yda1c.png
  [2]: https://i.stack.imgur.com/OMb0P.png

标签： flutterdart