更新对话框中的值

Question

我想在从服务器获取数据时在 Dialog 中显示进度值。取到第一个应该显示5%，取到第二个显示10%直到100%（共20个）

showSyncDialog(
      BuildContext context,
      Repository repo,
      BehaviorSubject<double> percentage) {
    double percent = 0.0;
    int count = 0;

    return showDialog(
        barrierDismissible: false,
        context: context,
        builder: (_) {
          return StatefulBuilder(builder: (context, StateSetter setState) {
            return Dialog(
              elevation: 0.0,
              child: FutureBuilder(
                  future: repo.getAdminList(urls),
                  builder: (context, snapshot) {
                    if (snapshot.hasData) {
                      return FutureBuilder<List<ABC>>(
                          future: repo.getList(),
                          builder: (context, snapshotDatas) {
                            if (snapshotDatas.hasData) {
                              for (var i in snapshotDatas.data!) {
                                repo.getItems(i.id!)
                                    .then((value) {
                                  percent = ((count++) / 20 * 100);
                                  print(percent.toString() + "efewfeeff");
                                  percentage.sink.add(percent);
                                  print(percentage.stream.value.toDouble());
                                });
                              }

                              return Padding(
                                padding: EdgeInsets.all(15.0),
                                child: LinearPercentIndicator(
                                  animation: true,
                                  lineHeight: 20.0,
                                  animationDuration: 2000,
                                  percent: percentage.stream.value.toDouble(),
                                  center:
                                      Text(percentage.stream.value.toString()),
                                  linearStrokeCap: LinearStrokeCap.roundAll,
                                  progressColor: Colors.greenAccent,
                                ),
                              );
                            } else {
                              return Text("No item");
                            }
                          });
                    } else {
                      return Text("No item");
                    }
                  }),
            );
          });  
        });
  }

输出

I/flutter (16036): 0.0efewfeeff
I/flutter (16036): 0.0
I/flutter (16036): 5.0efewfeeff
I/flutter (16036): 5.0
I/flutter (16036): 10.0efewfeeff
I/flutter (16036): 10.0
I/flutter (16036): 15.0efewfeeff
I/flutter (16036): 15.0
I/flutter (16036): 20.0efewfeeff
I/flutter (16036): 20.0
...

我的问题是对话框中的百分比值始终显示为 0.0，尽管控制台中显示的值在变化。如何更新对话框中的值？

Answer 1

使用 StatefulBuilder 在 Dialog 内部使用 setState 并仅在其中更新 Widgets。这是一个例子。

showDialog(
  context: context,
  builder: (context) {
    String contentText = "Content of Dialog";
    return StatefulBuilder(
      builder: (context, setState) {
        return AlertDialog(
          title: Text("Title of Dialog"),
          content: Text(contentText),
          actions: <Widget>[
            TextButton(
              onPressed: () => Navigator.pop(context),
              child: Text("Cancel"),
            ),
            TextButton(
              onPressed: () {
                setState(() {
                  contentText = "Changed Content of Dialog";
                });
              },
              child: Text("Change"),
            ),
          ],
        );
      },
    );
  },
);

更新对话框中的值

Update value in dialog

dialog

dart

flutter