Double-Tap Trouble: Conquering Multiple Tap Issues in Flutter

Ah, the joys of mobile app development!
As we craft our beautiful, intuitive, and engaging apps using Flutter, we must prepare for the unexpected. I am not talking about bugs or crashes here, but rather the inevitable encounter with an overexcited user whose fingers can’t resist the temptation to tap, tap, and tap some more.

Picture this: Jim is on his lunch break, scrolling through his favorite social media app. He stumbles upon a hilarious post that’s just perfect for pranking Dwight. Excitedly, Jim taps the “Share” button to send it to the office group chat, but nothing happens. Determined not to miss this golden opportunity, he taps the button again and again. When the app finally catches up, the office group chat is flooded with 17 identical messages. Awkward!!!

In this article, we’ll dive into the issue of “Multiple Tap” in Flutter and discuss the importance of implementing a prevention mechanism. By the end of this article, you’ll be well-equipped to handle Multiple Tap scenarios like a professional app developer.

The Reason :

When a user interacts with a button, most of the time the app initiates an API call behind the scenes, but there is no immediate visual feedback on the display. Consequently, the user assumes their initial tap was unsuccessful and proceeds to tap again, often compounding the problem.

The Prevention :

Thus far, we’ve determined that the multiple tap issue exists and that providing visual feedback to the user is essential. It’s clear that we must offer some form of visual indicator to communicate that the button is processing a task.
What’s better than showing a loader on the button? Just like this :

But unfortunately, this does not stop the over enthusiastic user from tapping and accidentally firing tons of API calls.

So let’s explore some prevention options along with showing that loader:

1. We can disable the button for a fixed amount of time and then enable it, the technical term for this is “debouncing”.
2. We can disable the button until the API call or a time-consuming operation is finished, and then enable the button again.

Debouncing Button Taps in Flutter

To implement this solution, we’ll create a reusable widget that debounces button taps. This widget will accept a callback and a debounce duration as arguments, ensuring that the button action is triggered only once within the specified time interval.

Here’s the code for the DebouncedButton widget:

import 'dart:async';
import 'package:flutter/material.dart';

class DebouncedButton extends StatefulWidget {
  final VoidCallback onPressed;
  final Widget child;
  final Duration debounceDuration;

  DebouncedButton({
    Key? key,
    required this.onPressed,
    required this.child,
    this.debounceDuration = const Duration(milliseconds: 500),
  }) : super(key: key);

  @override
  _DebouncedButtonState createState() => _DebouncedButtonState();
}

class _DebouncedButtonState extends State<DebouncedButton> {
  bool _isProcessing = false;
  Timer? _debounceTimer;

  void _handleTap() {
    if (_isProcessing) return;

    _isProcessing = true;
    widget.onPressed();

    _debounceTimer = Timer(widget.debounceDuration, () {
      _isProcessing = false;
    });
  }

  @override
  void dispose() {
    _debounceTimer?.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return ElevatedButton(
      onPressed: _handleTap,
      child: widget.child,
    );
  }
}

Now, let’s see how to use the DebouncedButton widget:

import 'package:flutter/material.dart';
import 'debounced_button.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('Debounced Button Example')),
        body: Center(
          child: DebouncedButton(
            onPressed: () {
              print('Button tapped');
            },
            child: Text('Tap me!'),
          ),
        ),
      ),
    );
  }
}

Using a Mixin with Future-based Button Debouncing

Now, let’s dive into a flexible solution using a mixin that waits for the future call to complete, instead of using a fixed timer. This approach ensures that the button remains disabled only for the duration of the API call, providing a more responsive user experience.

Here’s the code for the mixin:

mixin PreventMultipleTap on StatefulWidget {
  bool _isProcessing = false;

  Future<void> handleTap(Future<void> Function() onTap) async {
    if (_isProcessing) return;
    _isProcessing = true;
    try {
      await onTap();
    } finally {
       if (mounted) {
        setState(() {
          _isProcessing = false;
        });
      }
    }
  }
}

Now, let’s see how to use the PreventMultipleTap mixin in a StatefulWidget:

import 'package:flutter/material.dart';
import 'prevent_multiple_tap_mixin.dart';

class MyButton extends StatefulWidget {
  const MyButton({Key? key}) : super(key: key);

  @override
  _MyButtonState createState() => _MyButtonState();
}

class _MyButtonState extends State<MyButton> with PreventMultipleTap {
  @override
  Widget build(BuildContext context) {
    return ElevatedButton(
      onPressed: _isProcessing
          ? null
          : () async {
              await handleTap(() async {
                // Replace this with your actual API call or a time-consuming operation
                await Future.delayed(const Duration(seconds: 3));
                print('Operation completed');
              });
            },
      child: Text('Tap me!'),
    );
  }
}

By addressing the “Multiple Tap” issue in Flutter, you’ll create a seamless user experience that accommodates even the most enthusiastic tappers. With the knowledge provided in this article, you’re now equipped to handle multiple tap scenarios like a pro.

So, the next time Jim encounters a post that’s perfect for pranking Dwight during his lunch break, he can tap away without causing chaos in the Office group chat. Equipped with the knowledge and skills shared in this article, you can confidently handle multiple tap scenarios like a seasoned app developer. Go forth, and tap responsibly!

Hello everyone!! I am Debasmita. I fell in love with Flutter a long time ago and I am head over heels now. I am a Senior Mobile Developer at Peggy , Co-founder of Flutter Hiring Network and a public speaker. Check out recent updates from me in twitter, linkedIn, youtube, github.
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