An **input gesture** in Flutter allows users to interact with an application. Users can control the application by touching the screen, mouse, or keyboard.



# 
## List of input gestures in Flutter

* **Tap:** This means to touch the screen from the fingertip or mouse for a short time. This gesture has the following events:
  * `onTapDown`
  * `onTapUp`
  * `onTap`
  * `onTapCancel`




* **Double tap:** This means tapping the screen twice from the fingertip or double-clicking using a mouse. This gesture has the following events:
  * `onDoubleTap`

* **Long press:** Touch the screen from the fingertip or mouse for a long period. This gesture has the following events:
  * `onLongPress`

* **Drag and drop:** Press the screen from the fingertip and then drag it to another location. This gesture allows the drag functionalities in two ways:
  1. **Horizontal drag:** Horizontal drag gesture has the following events:
     * `onHorizontalDragStart`
     * `onHorizontalDragUpdate`
     * `onHorizontalDragEnd`
  2. **Vertical drag:** Vertical drag gesture has the following events:
     * `onVerticalDragStart`
     * `onVerticalDragStart`
     * `onVerticalDragStart`
  

* **Pan:** Press the screen with the fingertip and move anywhere without releasing it. This gesture has the following events:
  * `onPanStart`
  * `onPanUpdate`
  * `onPanEnd`


* **Pinch:** Zoom in or out with two fingers.



## Example of `onTapUp`

Let's discuss the example of the `onTap` event that will be executed when the user touches the screen:

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatefulWidget {
  @override
  _FirstApp createState() => _FirstApp();
}

class _FirstApp extends State<MyApp> {
  Color _rectangle = Colors.green;

  void _blockColor() {
    setState(() {
      _rectangle = _rectangle == Colors.green ? Colors.red : Colors.green;
    });
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: GestureDetector(
          onTap: _blockColor,
          child: Container(
            width: 1000,
            height: 1000,
            color: _rectangle,
          ),
        ),
      ),
    );
  }
}






import React from 'react';
import { shallow, configure } from 'enzyme';
import Adapter from 'enzyme-adapter-react-16';

configure({ adapter: new Adapter() });

import HelloWorld from './app';

var TestResult = function() {
    this.succeeded = false;
    this.reason = "";
    this.input = "";
    this.expected_output = "";
    this.actual_output = "";
}

export const executeTests = function() {

  var results = [];

  result = new TestResult();
  result.input = 'HelloWorld Component';
  result.expected_output = "span containing text 'Hello World'"

  let wrapper = shallow(<HelloWorld />);

  // Call your Challenge function here.

  let type = wrapper.type();
  let testSuccessful = true;
  let failureReason;

  if (type !== 'span') {
    testSuccessful = false;
    failureReason = "You need to render exactly one span HTML element";
  } else if (wrapper.props().children != "Hello World") {
     testSuccessful = false;
     failureReason = "You have rendered wrong message in your span element";
  }

  result.actual_output = wrapper.html();

  if (testSuccessful) {
    result.succeeded = true;
    result.reason = "Succeeded"
  } else {
    result.succeeded = false;
    result.reason = failureReason;
  }

  results.push(result);

  return results;
}


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## Explanation
**Lines 13–17:** The `_blockColor()` function will be called when the user taps the screen. This function will change the color on each tap from green to red and red to green.

**Lines 24–28:** We have set the container widget. This widget has a `width` of `1000`, a `height` of `100`, and a background `color` is set to `_rectangle`. This `_rectangle` will change color on each tap.

 


flutter.tar.gz

What is an input gesture in Flutter?

Flutter's input gestures include tap, double tap, long press, drag, pan, and pinch, enabling user interaction.

What is an input gesture in Flutter?

List of input gestures in Flutter

Example of onTapUp

Explanation

Example of `onTapUp`