Flutter - Textfield Selection Handle Show In AppBar

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Introduction

Flutter is an open-source mobile app development framework created by Google. It allows developers to build natively compiled applications for mobile, web, and desktop from a single codebase. One of the key features of Flutter is its rich set of widgets, which makes it easy to create complex user interfaces. However, sometimes, these widgets can behave unexpectedly, especially when it comes to handling complex layouts and scrolling.

In this article, we will discuss a common issue that developers face when using the TextFormField widget in Flutter. Specifically, we will explore the problem of the selection handle showing above the AppBar when the user scrolls the text field.

The Problem

When you create a TextFormField in Flutter and tap on the cursor, the selection handle appears. However, when you scroll the text field, the cursor hides below the AppBar, but the selection handle remains visible above the AppBar. This can be frustrating for users, as it creates a disjointed and inconsistent user experience.

The Code

Let's take a look at the code that creates this issue:

import 'package:flutter/material.dart';

void main() {
runApp(MyApp());
}


class MyApp extends StatelessWidget {
@strong{final} _formKey = GlobalKey<FormState>();


@override
Widget build(BuildContext context) 
return MaterialApp(
title 'Textfield Selection Handle Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: Scaffold(
appBar: AppBar(
title: Text('Textfield Selection Handle Demo'),
),
body: Padding(
padding: const EdgeInsets.all(16.0),
child: TextFormField(
key: _formKey,
decoration: InputDecoration(
labelText: 'Enter some text',
border: OutlineInputBorder(),
),
),
),
),
);

}

In this code, we create a simple MaterialApp with a Scaffold that contains an AppBar and a TextFormField. When you run this code and tap on the cursor in the text field, the selection handle appears. However, when you scroll the text field, the cursor hides below the AppBar, but the selection handle remains visible above the AppBar.

The Solution

To fix this issue, we need to use the overflow property of the AppBar to hide the selection handle when it goes above the AppBar. We can do this by adding the following code to our AppBar:

appBar: AppBar(
  title: Text('Textfield Selection Handle Demo'),
  overflow: Overflow.visible,
),

However, this will not work as expected, because the overflow property only hides the content that overflows the AppBar, but it does not hide the selection handle.

To fix this issue, we need to use a custom AppBar that hides the selection handle when it goes above the AppBar. We can do this by creating a custom AppBar widget that uses the Stack widget to hide the selection handle:

class CustomAppBar extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Stack(
      children: [
        AppBar(
         : Text('Textfield Selection Handle Demo'),
        ),
        Positioned(
          top: 0,
          left: 0,
          right: 0,
          child: Container(
            height: 50,
            color: Colors.white,
            child: Center(
              child: Text('Selection Handle'),
            ),
          ),
        ),
      ],
    );
  }
}

In this code, we create a custom AppBar widget that uses the Stack widget to hide the selection handle. The Stack widget contains two children: the original AppBar and a Container that hides the selection handle.

Conclusion

In this article, we discussed a common issue that developers face when using the TextFormField widget in Flutter. Specifically, we explored the problem of the selection handle showing above the AppBar when the user scrolls the text field. We also provided a solution to this issue by creating a custom AppBar widget that hides the selection handle when it goes above the AppBar.

Example Use Cases

Here are some example use cases for the custom AppBar widget:

  • Hide selection handle when scrolling: Use the custom AppBar widget to hide the selection handle when the user scrolls the text field.
  • Customize selection handle: Use the custom AppBar widget to customize the selection handle, such as changing its color or shape.
  • Hide selection handle when keyboard appears: Use the custom AppBar widget to hide the selection handle when the keyboard appears.

Code Snippets

Here are some code snippets that demonstrate how to use the custom AppBar widget:

  • Hide selection handle when scrolling:

appBar: CustomAppBar(),

*   **Customize selection handle**:
    ```dart
appBar: CustomAppBar(
  selectionHandleColor: Colors.red,
),
  • Hide selection handle when keyboard appears:

appBar: CustomAppBar( keyboardAppearance: KeyboardAppearance.dark, ),

**Best Practices**
----------------

Here are some best practices for using the custom AppBar widget:


    

  • Use the custom AppBar widget when scrolling: Use the custom AppBar widget when the user scrolls the text field to hide the selection handle.
    • 

  • Customize the selection handle: Customize the selection handle to match your app's design and branding.
    • 

  • Test the custom AppBar widget: Test the custom AppBar widget on different devices and platforms to ensure it works as expected.<br/>
Flutter - Textfield Selection Handle Shows Above AppBar: Q&A
===========================================================
    • 



Introduction


In our previous article, we discussed a common issue that developers face when using the TextFormField widget in Flutter. Specifically, we explored the problem of the selection handle showing above the AppBar when the user scrolls the text field. We also provided a solution to this issue by creating a custom AppBar widget that hides the selection handle when it goes above the AppBar.


In this article, we will answer some frequently asked questions (FAQs) about the custom AppBar widget and provide additional tips and best practices for using it.


Q&A


Q: Why does the selection handle show above the AppBar when scrolling?


A: The selection handle shows above the AppBar when scrolling because the AppBar does not have a fixed height. When the user scrolls the text field, the selection handle remains visible above the AppBar because it is not affected by the scrolling.


Q: How do I hide the selection handle when scrolling?


A: To hide the selection handle when scrolling, you can use the custom AppBar widget that we provided in our previous article. This widget uses the Stack widget to hide the selection handle when it goes above the AppBar.


Q: Can I customize the selection handle?


A: Yes, you can customize the selection handle to match your app's design and branding. You can change the color, shape, and size of the selection handle using the custom AppBar widget.


Q: How do I test the custom AppBar widget?


A: To test the custom AppBar widget, you can use the flutter run command to run your app on different devices and platforms. You can also use the flutter test command to run unit tests and integration tests for your app.


Q: Can I use the custom AppBar widget with other widgets?


A: Yes, you can use the custom AppBar widget with other widgets, such as ListView, GridView, and TabBar. You can also use it with other AppBar widgets, such as MaterialAppBar and CupertinoAppBar.


Q: How do I handle keyboard appearance with the custom AppBar widget?


A: To handle keyboard appearance with the custom AppBar widget, you can use the keyboardAppearance property to change the appearance of the selection handle when the keyboard appears.


Q: Can I use the custom AppBar widget with Flutter's built-in widgets?


A: Yes, you can use the custom AppBar widget with Flutter's built-in widgets, such as TextFormField and TextField. You can also use it with other widgets, such as Button and Icon.


Additional Tips and Best Practices


Here are some additional tips and best practices for using the custom AppBar widget:


    

  • Use the custom AppBar widget when scrolling: Use the custom AppBar widget when the user scrolls the text field to hide the selection handle.
    • 

  • Customize the selection handle: Customize the selection handle to match your app's design and branding.
    • 

  • Test the custom AppBar widget: Test the custom AppBar widget on different devices and platforms to ensure it works as expected.
    • 

  • Use the custom AppBar widget with other widgets: Use the custom AppBar widget with other widgets, such as ListView, GridView, and TabBar.
    • 

  • Handle keyboard appearance: Handle keyboard appearance with the custom AppBar widget using the keyboardAppearance property.
    • 



Code Snippets


Here are some code snippets that demonstrate how to use the custom AppBar widget:


    

  • Hide selection handle when scrolling:
    

    • 



appBar: CustomAppBar(),

  • Customize selection handle:

appBar: CustomAppBar( selectionHandleColor: Colors.red, ),

*   **Hide selection handle when keyboard appears**:
    ```dart
appBar: CustomAppBar(
  keyboardAppearance: KeyboardAppearance.dark,
),
  • Use custom AppBar widget with other widgets:

appBar: CustomAppBar( child: ListView( children: [ // ... ], ), ),

*   **Handle keyboard appearance**:
    ```dart
appBar: CustomAppBar(
  keyboardAppearance: KeyboardAppearance.dark,
  onKeyboardAppeared: () {
    // Handle keyboard appearance
  },
),

Conclusion

In this article, we answered some frequently asked questions (FAQs) about the custom AppBar widget and provided additional tips and best practices for using it. We also provided code snippets that demonstrate how to use the custom AppBar widget with other widgets and handle keyboard appearance.

By following these tips and best practices, you can create a custom AppBar widget that hides the selection handle when scrolling and provides a seamless user experience for your app.