如何在按鈕小部件中顯示進度指示器（如圖所示）

Question

我是 flutter 的新手。 我已經實現了一個按鈕，我想在單擊按鈕時像下面這樣進度指示器。

我已經使用百分比指標package 來實現，但它沒有正確存檔。

我的代碼是，

class DownloadIndicatorWidget extends StatefulWidget {
  bool download = false;

  @override
  _DownloadIndicatorWidgetState createState() => _DownloadIndicatorWidgetState();
}

class _DownloadIndicatorWidgetState extends State<DownloadIndicatorWidget> {

  @override
  Widget build(BuildContext context) {
    return widget.download?ClipRRect(
      borderRadius: BorderRadius.circular(10),
      child: Container(
        height: 40,
      decoration: BoxDecoration(
          border: Border.all(
            color: Color(0xff9F00C5), //                   <--- border color
            width: 10.0,
          ),
          borderRadius: BorderRadius.circular(10.0)
      ),
        child: LinearPercentIndicator(
//      width: MediaQuery.of(context).size.width -
//        width:107,
          animation: true,
          lineHeight: 40.0,
          animationDuration: 2500,
          percent: 1,
          center: Text(
              "Downloading...",
              textAlign: TextAlign.center,
              style: TextStyle(
                  color: Colors.black,
                  fontWeight: FontWeight.w800,
                  fontSize: 14
              )),
          linearStrokeCap: LinearStrokeCap.roundAll,
          progressColor: Color(0xff9F00C5),
          backgroundColor: Colors.white,
        ),
      ),
    ):RaisedButton(
      onPressed: () {
        setState(() {
          widget.download = true;
        });
      },
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(10.0)),
      padding: EdgeInsets.all(0.0),
      child: Ink(
        decoration: BoxDecoration(
            gradient: LinearGradient(colors: [Color(0xff9F00C5), Color(0xff9405BD),Color(0xff7913A7),Color(0xff651E96), Color(0xff522887)],
              begin: Alignment.topCenter,
              end: Alignment.bottomCenter,
            ),
            borderRadius: BorderRadius.circular(10.0)
        ),
        child: Container(
          constraints: BoxConstraints(maxWidth: 300.0, minHeight: 50.0),
          alignment: Alignment.center,
          child: Text(
            "Download",
            textAlign: TextAlign.center,
            style: TextStyle(
                color: Colors.white,
                fontWeight: FontWeight.w800,
                fontSize: 18
            ),
          ),
        ),
      ),
    );
  }
}

那么，如何正確實現像圖像一樣存檔呢？ 如果有任何其他方法可以實現它，請建議我我真的需要這個。 提前致謝！

Answer 1

此代碼可能會對您有所幫助。

import 'dart:async';

import 'package:flutter/material.dart';

class Progress extends StatefulWidget {
  @override
  _ProgressState createState() => _ProgressState();
}

class _ProgressState extends State<Progress> {
  double progress = 0;

  void initState() {
    super.initState();

    Timer.periodic(Duration(milliseconds: 100), (Timer t) {
      setState(() {
        if (progress > 120) {
          progress = 0;
        } else {
          progress += 5;
        }
      });
    });
  }

  @override
  Widget build(BuildContext context) {
    return Center(
      child: FlatButton(
        onPressed: () {},
        child: ClipRRect(
            borderRadius: BorderRadius.circular(10),
            child: Container(
                height: 45,
                width: 120,
                decoration: BoxDecoration(
                    borderRadius: BorderRadius.circular(10),
                    border: Border.all(
                      color: Colors.indigo,
                      width: 1,
                    )),
                child: Stack(
                  children: <Widget>[
                    AnimatedContainer(
                      color: Colors.indigo,
                      width: progress,
                      duration: Duration(milliseconds: 100),
                      curve: Curves.fastOutSlowIn,
                    ),
                    Center(child: Text("Downloading...")),
                  ],
                ))),
      ),
    );
  }
}