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Flutter-Web: Mouse hover -> Change cursor to pointer

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走了就别回头了
走了就别回头了 2021-02-05 06:59

How can the cursor appearance be changed within Flutter? I know that with the Listener() Widget we can listen for Mouse-Events, but I haven\'t found any information regarding h

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  • 暗喜
    2021-02-05 06:59

    Starting with dev channel build version 1.19.0–3.0.pre there is built-in support for the pointer cursor. The same method as bellow is used with the difference that is applied to the Flutter app container element flt-glass-pane. Using the bellow method will just duplicate the behavior.

    In order to override the pointer cursor, you can use the bellow method but applied on the flt-glass-pane element.

    A workaround for this is the following:

    1. You have to set an id (for example app-container on the entire body of the app's index.html template).

    This is how your index.html will look like:

    <!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>My awesome app</title>
</head>
<body id="app-container">
  <script src="main.dart.js" type="application/javascript"></script>
</body>
</html>
    1. Next, you have to create a wrapper dart class. I called it hand_cursor.dart:
    import 'package:flutter_web/gestures.dart';
import 'package:flutter_web/widgets.dart';
import 'package:universal_html/html.dart' as html;
// see https://pub.dev/packages/universal_html

class HandCursor extends MouseRegion {

  // get a reference to the body element that we previously altered 
  static final appContainer = html.window.document.getElementById('app-container');

  HandCursor({Widget child}) : super(
    onHover: (PointerHoverEvent evt) {
      appContainer.style.cursor='pointer';
      // you can use any of these: 
      // 'help', 'wait', 'move', 'crosshair', 'text' or 'pointer'
      // more options/details here: http://www.javascripter.net/faq/stylesc.htm
    },
    onExit: (PointerExitEvent evt) {
      // set cursor's style 'default' to return it to the original state
      appContainer.style.cursor='default';
    },
    child: child
  );

}
    1. After that, wherever you want to have the hand cursor shown, you have to wrap your element in this HandCursor wrapper. See the class awesome_button.dart bellow:
    import 'package:awesome_app/widgets/containers/hand_cursor.dart';
import 'package:flutter_web/material.dart';
import 'package:flutter_web/widgets.dart';

class AwesomeButton extends StatelessWidget {

  @override
  Widget build(BuildContext context) {
    return Stack(
      children: <Widget>[
        HandCursor(
          child: IconButton(
            onPressed: () {
              // do some magic
            },
            icon: Icon(Icons.star)
          ),
        )
      ],
    );
  }

}

    A short explanation can be found here.

    A more versatile update, that works on the new web projects created with the master channel of Flutter, can be found here.

    I hope it helps.

    0 讨论(0)
  • 别那么骄傲
    2021-02-05 07:03

    From Flutter beta version 1.19.0-4.1.pre, add id to body and set cursor of that doesn't work. Because flt-glass-pane is replacing the cursor. So the solution is that set cursor directly to flt-glass-pane.

    Below is the update that is working.

    class HandCursor extends MouseRegion {
    static final appContainer = html.window.document.querySelectorAll('flt-glass-pane')[0];
    HandCursor({Widget child}) : super(
        onHover: (PointerHoverEvent evt) {
            appContainer.style.cursor='pointer';
        },
        onExit: (PointerExitEvent evt) {
            appContainer.style.cursor='default';
        },
        child: child
    );    
}
    0 讨论(0)
  • 暗喜
    2021-02-05 07:09

    Adapted answer by Constantin Stan

    For those who want to have the click effect similar to InkWell widget and with border radius option:

    Add to your pubspec.yaml file

    dependencies:
  universal_html: ^1.1.4

    Then add to the index.html file the following the tag <body id="app-container"> as below:

    <!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>Your App Title</title>
</head>
<body id="app-container">
  <script src="main.dart.js" type="application/javascript"></script>
</body>
</html>

    Finally create the following widget and use encapsulated all the necessary widgets:

    import 'package:flutter/foundation.dart';
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:universal_html/prefer_sdk/html.dart' as html;

class InkWellMouseRegion extends InkWell {
  InkWellMouseRegion({
    Key key,
    @required Widget child,
    @required GestureTapCallback onTap,
    double borderRadius = 0,
  }) : super(
          key: key,
          child: !kIsWeb ? child : HoverAware(child: child),
          onTap: onTap,
          borderRadius: BorderRadius.circular(borderRadius),
        );
}

class HoverAware extends MouseRegion {

  // get a reference to the body element that we previously altered 
  static final appContainer = html.window.document.getElementById('app-container');

  HoverAware({Widget child}) : super(
    onHover: (PointerHoverEvent evt) {
      appContainer.style.cursor='pointer';
      // you can use any of these: 
      // 'help', 'wait', 'move', 'crosshair', 'text' or 'pointer'
      // more options/details here: http://www.javascripter.net/faq/stylesc.htm
    },
    onExit: (PointerExitEvent evt) {
      // set cursor's style 'default' to return it to the original state
      appContainer.style.cursor='default';
    },
    child: child
  );

}
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  • 悲&欢浪女
    2021-02-05 07:11

    I believe that mouse events won't work on the web, Listener Widget was demoed on Google I/O 2019 and worked with mouse, but that was as a ChromeOS app and not a web app.

    According to Flutter web on GitHub:

    At this time, desktop UI interactions are not fully complete, so a UI built with flutter_web may feel like a mobile app, even when running on a desktop browser.

    0 讨论(0)
  • 名媛妹妹
    2021-02-05 07:16

    I had difficulties finding documentation on the now built-in support. Here is what helped me: https://github.com/flutter/flutter/issues/58260

    And this did the trick for me, without changing index.html etc.

    MouseRegion(
  cursor: SystemMouseCursors.click,
    child: GestureDetector(
      child: Icon(
        Icons.add_comment,
        size: 20,
        ),
      onTap: () {},
    ),
  ),
    0 讨论(0)
  • 甜味超标
    2021-02-05 07:22

    The previous method is deprecated. Here is the updated code

    import 'package:flutter/gestures.dart';
import 'package:flutter/widgets.dart';
import 'package:universal_html/prefer_sdk/html.dart' as html;

class HandCursor extends MouseRegion {
  static final appContainer = html.window.document.getElementById('app-container');
  HandCursor({Widget child})
      : super(
          onHover: (PointerHoverEvent evt) {
            appContainer.style.cursor = 'pointer';
          },
          onExit: (PointerExitEvent evt) {
            appContainer.style.cursor = 'default';
          },
          child: child,
        );
}

    And in your pubspec.yaml file, add universal_html as a package as a dependency. The version may change.

    dependencies:
  flutter:
    sdk: flutter
  universal_html: ^1.1.4

    You still want to have an id of app-container attached to the body of your html. Here is my html file.

    <!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>Your App Title</title>
</head>
<body id="app-container">
  <script src="main.dart.js" type="application/javascript"></script>
</body>
</html>

    You want to put the code for the HandCursor widget in its own file. You can call it hand_cursor.dart. And to use it on the widget you want the hand to show up on, import it into the file you're working on and wrap the widget you want in the HandCursor widget.

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