Question

我有一个stopwatch窗口小部件，该窗口小部件从页面上的Detailed Activity页面调用，该窗口在页面加载时开始。如何使它在后台连续运行，以便当我从Detailed Activity导航到Home页面时，可以显示同一秒表的时间？

此刻，Home页显示上次保存的时间（到变量中）。取而代之的是，我希望这能继续每秒增加两个屏幕之间的切换，反之亦然。我尝试在startWatch()页面中添加initState()和Home方法，但不知道在导航至Detailed Activity页面时如何传递秒表值

为进一步说明这一点，我的想法是在Detailed Activity页上，例如00:15:00->将其传递到Home页并调用initState（）以再次自动启动计时器。这行得通吗？

Timer.dart

class NewStopWatch extends StatefulWidget {

  @override
  _NewStopWatchState createState() => new _NewStopWatchState();
}

class _NewStopWatchState extends State<NewStopWatch> {

  static _NewStopWatchState stopwatch;
  Stopwatch watch = new Stopwatch();
  Timer timer;
  bool startStop = true;
  static String elapsedTime = '';
  String duration;

  updateTime(Timer timer) {
    if (watch.isRunning) {
      setState(() {
        elapsedTime = transformMilliSeconds(watch.elapsedMilliseconds);
        User.getCurrentUser().getCurrentActivity().setElapsedTime(elapsedTime);
      });
    }
  }
@override
  Widget build(BuildContext context) {

    return new Container(
            padding: EdgeInsets.all(20.0),
            child: new Column(
              children: <Widget>[
                new Text(elapsedTime, style: new TextStyle(fontSize: 25.0)),
                SizedBox(height: 20.0),
                new Row(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: <Widget>[
                FloatingActionButton(
                  heroTag: "btn1",
                  backgroundColor: Colors.red,
                  onPressed: () => startOrStop(),
                  child: Icon(Icons.pause)),
                SizedBox(width: 20.0),
                FloatingActionButton(
                  heroTag: "btn2",
                  backgroundColor: Colors.green,
                  onPressed: () => completeActivity(),
                  child: Icon(Icons.check)),
                  ],
                )
              ],
            ));
  }

  void initState() {
    super.initState();
    WidgetsBinding.instance
        .addPostFrameCallback((_) => startWatch());
  }

  startOrStop() {
    if(startStop) {
      startWatch();
    } else {
      stopWatch();
    }
  }

  startWatch() {
    setState(() {
      startStop = false;
      watch.start();
      timer = Timer.periodic(Duration(milliseconds: 100), updateTime);
    });
  }

  stopWatch() {
    setState(() {
      startStop = true;
      watch.stop();
      setTime();
    });
  }

  resetWatch() {
    watch.reset();
    setTime();
  }

  setTime() {
    var timeSoFar = watch.elapsedMilliseconds;
    setState(() {
      elapsedTime = transformMilliSeconds(timeSoFar);
    });
  }

  completeActivity() { //do I call activity.stopActivity()?
    return showDialog(
          context: context,
          builder: (context) => new AlertDialog(
                title: new Text('Complete Activity?',
                    style: new TextStyle(color: Colors.black, fontSize: 20.0)),
                actions: <Widget>[
                  new FlatButton(
                    onPressed: () {
                      duration = elapsedTime;
                      print("Current activitiy: ${User.getCurrentUser().getCurrentActivity()}");
                      // User.getCurrentUser().completeActivity();
                      User.getCurrentUser().addPastActivity(User.getCurrentUser().getCurrentActivity());
                      User.getCurrentUser().getCurrentActivity().setStatus(ActivityStatus.completed);
                      User.getCurrentUser().setCurrentActivity(null);
                      Navigator.push(context, MaterialPageRoute(builder: (context) => FrontPage()));
                      // Navigator.popUntil(context, ModalRoute.withName("/"),);
                    },
                    child:
                        new Text('Yes', style: new TextStyle(fontSize: 18.0)),
                  ),
                  new FlatButton(
                    onPressed: () => Navigator.pop(context), // this line dismisses the dialog
                    child: new Text('No', style: new TextStyle(fontSize: 18.0)),
                  )
                ],
              ),
        ) ??
        false;
    }

  transformMilliSeconds(int milliseconds) {
    int hundreds = (milliseconds / 10).truncate();
    int seconds = (hundreds / 100).truncate();
    int minutes = (seconds / 60).truncate();
    int hours = (minutes / 60).truncate();

    String hoursStr = (hours % 60).toString().padLeft(2, '0');
    String minutesStr = (minutes % 60).toString().padLeft(2, '0');
    String secondsStr = (seconds % 60).toString().padLeft(2, '0');

    return "$hoursStr:$minutesStr:$secondsStr";
  }

   static String getElapsedTime() {
    return elapsedTime;
  }
}

Answer 1

由于您已经发布了很多代码，因此对于此解决方案是否可行，我尚不清楚100％，但是它缺少您实际显示NewStopWatch的部分，但我希望此解决方案有帮助：

在您的NewStopWath类的init方法中将秒表和计时器作为参数传递，并从您的主页（也希望它们显示在该页面上）传递它们……我想它是FrontPage。

像这样：

import tkinter as tk

# colors for certain characters    
colormap = {'b':'blue', 'c':'cyan', 'g':'green', 'm':'magenta', 'o':'orange', 'p':'pink', 'r':'red', 'y':'yellow'}

def on_key(event):
    if event.char in colormap:
        # attach a tag (the character itself) if the character is in the colormap
        event.widget.tag_add(event.char, 'insert-1c')

root = tk.Tk()

text = tk.Text(root)
text.pack()
text.bind('<KeyRelease>', on_key) # on_key() will be executed when a key is pressed inside Text widget
# setup colors for certain characters using tag_config(...)
for c in colormap:
    text.tag_config(c, foreground=colormap[c])

root.mainloop()

请确保检查是否应删除timer = Timer.periodic（Duration（毫秒：100），updateTime）;从startWatch（） 也许您不需要将它作为参数传递

颤振：切换屏幕时连续运行秒表

1 个答案: