Implement React Native Pressable onLongPress for Dragging Motion Event

In React Native, handling touch gestures like long presses and drags can add a dynamic and interactive element to your app. One common use case is enabling an element to be moved around the screen by long-pressing and dragging it. While React Native provides built-in touch event handlers like `onPress`, `onLongPress`, and `onMoveShouldSetPanResponder`, it doesn’t offer a built-in mechanism to combine these gestures for dragging behavior. However, by leveraging the `Pressable` component and combining it with the PanResponder API, you can create a smooth dragging experience.

In this article, we’ll

Explore How to Implement React Native Pressable onLongPress for Dragging Motion Event

Prerequisites

Before diving into the code, make sure you have the following:
– React Native environment set up.
– Basic understanding of React Native components like `View`, `Pressable`, and `Text`.

Key Concepts

– Pressable` Component: A core component in React Native used to detect touch events like `onPress`, `onLongPress`, `onPressIn`, and `onPressOut`.
– PanResponder: A utility in React Native that allows you to track and respond to touch gestures like dragging and panning across the screen.

Steps to Implement Dragging on LongPress

We will create a component where you can long-press on a `Pressable` element to initiate a drag. When the user presses and holds the element, they can drag it around the screen.

1. Set Up Your React Native Project

If you don’t have a project set up yet, you can create one using:

bash

npx react-native init DraggingApp
cd DraggingApp

2. Install Dependencies

We’ll be using the built-in `PanResponder` and `Pressable` components, so no additional libraries are required.

3. Create the Dragging Component

Here’s a simple implementation using `Pressable` for detecting long presses and `PanResponder` for handling drag gestures.

javascript

import React, { useState, useRef } from ‘react’;
import { View, Text, PanResponder, Animated, StyleSheet } from ‘react-native’;

const DraggableItem = () => {
// State to track the position of the draggable element
const [isDragging, setIsDragging] = useState(false);
const pan = useRef(new Animated.ValueXY()).current; // Animated value to control the drag

// Create a PanResponder instance to track the drag motion
const panResponder = useRef(
PanResponder.create({
onStartShouldSetPanResponder: () => true,
onMoveShouldSetPanResponder: () => true,
onPanResponderGrant: () => {
// When dragging starts, set the dragging state to true
setIsDragging(true);
},
onPanResponderMove: (e, gestureState) => {
// Update the position of the element as the user drags
pan.setValue({
x: gestureState.dx,
y: gestureState.dy,
});
},
onPanResponderRelease: () => {
// When drag ends, reset the dragging state
setIsDragging(false);
},
})
).current;

return (
<View style={styles.container}>
<Pressable
onLongPress={() => {
// This event triggers when the user long-presses
console.log(‘Long press detected!’);
}}
>
<Animated.View
{…panResponder.panHandlers} // Attach the panHandlers to the draggable element
style={[styles.box, { transform: pan.getTranslateTransform() }]}
>
<Text style={styles.text}>Drag Me</Text>
</Animated.View>
</Pressable>
{isDragging && <Text style={styles.status}>Dragging…</Text>}
</View>
);
};

const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: ‘center’,
alignItems: ‘center’,
backgroundColor: ‘#f0f0f0’,
},
box: {
width: 100,
height: 100,
backgroundColor: ‘#4CAF50’,
justifyContent: ‘center’,
alignItems: ‘center’,
borderRadius: 8,
},
text: {
color: ‘#fff’,
fontWeight: ‘bold’,
},
status: {
marginTop: 20,
fontSize: 18,
color: ‘gray’,
},
});

export default DraggableItem;

4. Explanation of the Code

1. State Management

We use the `useState` hook to track whether the element is being dragged. The `isDragging` state is used to show the dragging status message.

2. Animated Value

We use `Animated.ValueXY()` to create an animated value for the position of the draggable element. This allows for smooth transitions as the user moves the element.

3. PanResponder: The `PanResponder` is responsible for handling drag gestures

– onStartShouldSetPanResponder: This function returns `true` when a touch gesture should start tracking, meaning when the user starts interacting with the element.
– onMoveShouldSetPanResponder: This function returns `true` to allow movement tracking.
– onPanResponderGrant: This event is triggered when the drag gesture starts. It sets the `isDragging` state to `true`.
– onPanResponderMove: As the user moves the element, we update its position using the `pan.setValue()` method.
– onPanResponderRelease: When the user releases the element, the `isDragging` state is set to `false`.

4. Pressable` Component

The `Pressable` component is used to detect a `onLongPress` event. You can add additional logic inside the `onLongPress` callback to trigger actions when the user long presses on the element.

5. Transforming the Element

The `transform` style with `pan.getTranslateTransform()` is used to apply the updated position values from `PanResponder` to the element as it is dragged.

5. Styling and UI

The `View` and `Text` components provide basic layout and content for the draggable box. The `box` style defines the look of the draggable element, which has a green background and rounded corners. The `status` text shows when the element is being dragged.

Conclusion

Using `Pressable` and `PanResponder` together allows you to handle complex gestures like long presses followed by dragging motions in React Native. This combination enables interactive UIs where users can press and hold to drag elements around the screen.

You can extend this further by adding bounds to constrain the dragging area or by implementing custom animations when the drag starts or ends. Experiment with different gestures to create unique user experiences in your React Native app! Hope this article from hire tech firms helped you!