CircularProgressIndicator

CircularProgressIndicator

嗨,我已经设计了忘记密码屏幕和按钮点击集成FireBase。我想在用户单击按钮时显示CircularProgressIndicator,并在FireBase执行完成时将其取消。
有人知道怎么做吗?我想让CircularProgressIndicator在设备的中心。

class ForgotPasswordScreen extends StatelessWidget {

  final emailController = new TextEditingController();
  final authHandler = new Auth();

  @override
  Widget build(BuildContext context) {
    return new Scaffold(body: Container(
      height: MediaQuery.of(context).size.height,
      decoration: BoxDecoration(
        color: Colors.white,
      ),
      child: new Column(
        crossAxisAlignment: CrossAxisAlignment.center,
        mainAxisSize: MainAxisSize.max,
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          new Row(
            children: <Widget>[
              new Expanded(
                child: new Padding(
                  padding: const EdgeInsets.only(left: 40.0),
                  child: new Text(
                    "EMAIL",
                    style: TextStyle(
                      fontWeight: FontWeight.bold,
                      color: Colors.redAccent,
                      fontSize: 15.0,
                    ),
                  ),
                ),
              ),
            ],
          ),
          new Container(
            width: MediaQuery.of(context).size.width,
            margin: const EdgeInsets.only(left: 40.0, right: 40.0, top: 10.0),
            alignment: Alignment.center,
            decoration: BoxDecoration(
              border: Border(
                bottom: BorderSide(
                    color: Colors.redAccent,
                    width: 0.5,
                    style: BorderStyle.solid),
              ),
            ),
            padding: const EdgeInsets.only(left: 0.0, right: 10.0),
            child: new Row(
              crossAxisAlignment: CrossAxisAlignment.center,
              mainAxisAlignment: MainAxisAlignment.start,
              children: <Widget>[
                new Expanded(
                  child: TextField(
                    controller: emailController,
                    textAlign: TextAlign.left,
                    decoration: InputDecoration(
                      border: InputBorder.none,
                      hintText: 'PLEASE ENTER YOUR EMAIL',
                      hintStyle: TextStyle(color: Colors.grey),
                    ),
                  ),
                ),
              ],
            ),
          ),
          Divider(
            height: 24.0,
          ),
          new Container(
            width: MediaQuery.of(context).size.width,
            margin: const EdgeInsets.only(left: 30.0, right: 30.0, top: 20.0),
            alignment: Alignment.center,
            child: new Row(
              children: <Widget>[
                new Expanded(
                  child: new FlatButton(
                    shape: new RoundedRectangleBorder(
                      borderRadius: new BorderRadius.circular(30.0),
                    ),
                    color: Colors.redAccent,
                    onPressed: () => authHandler.sendPasswordResetEmail(emailController.text).then((void nothing) {
                      print("done");
                    }).catchError((e) => print(e)),
                    child: new Container(
                      padding: const EdgeInsets.symmetric(
                        vertical: 20.0,
                        horizontal: 20.0,
                      ),
                      child: new Row(
                        mainAxisAlignment: MainAxisAlignment.center,
                        children: <Widget>[
                          new Expanded(
                            child: Text(
                              "FORGOT PASSWORD",
                              textAlign: TextAlign.center,
                              style: TextStyle(
                                  color: Colors.white,
                                  fontWeight: FontWeight.bold),
                            ),
                          ),
                        ],
                      ),
                    ),
                  ),
                ),
              ],
            ),
          ),
        ],
      ),
    ));
  }

}

最佳答案

好的,首先你得稍微修改一下你的代码。
Stateless更改为Stateful以管理小部件的状态,并放置一个名为isLoading的全局变量。
您可以使用该变量,当您按下按钮时设置为isLoadingtrue,完成后设置为isLoadingfalse。
build方法中添加验证以在isLoading为真时显示循环进程,否则显示字段。
此处为代码示例:

    class ForgotPasswordScreen extends StatefulWidget {
      @override
      ForgotPasswordScreenState createState() {
        return new ForgotPasswordScreenState();
      }
    }

    class ForgotPasswordScreenState extends State<ForgotPasswordScreen> {
      final emailController = new TextEditingController();
      final authHandler = new Auth();
      bool isLoading = false;

      @override
      Widget build(BuildContext context) {
        return new Scaffold(
            body: Container(
                height: MediaQuery.of(context).size.height,
                decoration: BoxDecoration(
                  color: Colors.white,
                ),
                child: isLoading
                    ? Center(
                        child: CircularProgressIndicator(),
                      )
                    : new Column(
                        crossAxisAlignment: CrossAxisAlignment.center,
                        mainAxisSize: MainAxisSize.max,
                        mainAxisAlignment: MainAxisAlignment.center,
                        children: <Widget>[
                          new Row(
                            children: <Widget>[
                              new Expanded(
                                child: new Padding(
                                  padding: const EdgeInsets.only(left: 40.0),
                                  child: new Text(
                                    "EMAIL",
                                    style: TextStyle(
                                      fontWeight: FontWeight.bold,
                                      color: Colors.redAccent,
                                      fontSize: 15.0,
                                    ),
                                  ),
                                ),
                              ),
                            ],
                          ),
                          new Container(
                            width: MediaQuery.of(context).size.width,
                            margin: const EdgeInsets.only(
                                left: 40.0, right: 40.0, top: 10.0),
                            alignment: Alignment.center,
                            decoration: BoxDecoration(
                              border: Border(
                                bottom: BorderSide(
                                    color: Colors.redAccent,
                                    width: 0.5,
                                    style: BorderStyle.solid),
                              ),
                            ),
                            padding: const EdgeInsets.only(left: 0.0, right: 10.0),
                            child: new Row(
                              crossAxisAlignment: CrossAxisAlignment.center,
                              mainAxisAlignment: MainAxisAlignment.start,
                              children: <Widget>[
                                new Expanded(
                                  child: TextField(
                                    controller: emailController,
                                    textAlign: TextAlign.left,
                                    decoration: InputDecoration(
                                      border: InputBorder.none,
                                      hintText: 'PLEASE ENTER YOUR EMAIL',
                                      hintStyle: TextStyle(color: Colors.grey),
                                    ),
                                  ),
                                ),
                              ],
                            ),
                          ),
                          Divider(
                            height: 24.0,
                          ),
                          new Container(
                            width: MediaQuery.of(context).size.width,
                            margin: const EdgeInsets.only(
                                left: 30.0, right: 30.0, top: 20.0),
                            alignment: Alignment.center,
                            child: new Row(
                              children: <Widget>[
                                new Expanded(
                                  child: new FlatButton(
                                    shape: new RoundedRectangleBorder(
                                      borderRadius: new BorderRadius.circular(30.0),
                                    ),
                                    color: Colors.redAccent,
                                    onPressed: () {
                                      setState(() {
                                        isLoading = true;
                                      });
                                      authHandler
                                          .sendPasswordResetEmail(
                                              emailController.text)
                                          .then((void nothing) {
                                        print("done");
                                        setState(() {
                                          isLoading = false;
                                        });
                                      }).catchError((e) => print(e));
                                    },
                                    child: new Container(
                                      padding: const EdgeInsets.symmetric(
                                        vertical: 20.0,
                                        horizontal: 20.0,
                                      ),
                                      child: new Row(
                                        mainAxisAlignment: MainAxisAlignment.center,
                                        children: <Widget>[
                                          new Expanded(
                                            child: Text(
                                              "FORGOT PASSWORD",
                                              textAlign: TextAlign.center,
                                              style: TextStyle(
                                                  color: Colors.white,
                                                  fontWeight: FontWeight.bold),
                                            ),
                                          ),
                                        ],
                                      ),
                                    ),
                                  ),
                                ),
                              ],
                            ),
                          ),
                        ],
                      )));
      }
    }

关于android - 如何在flutter中使用CircularProgressIndicator,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/51883112/

10-09 07:56