What is the ScrollView component and how to use it in React Native?-JS Tutorial-php.cn

What is the ScrollView component and how to use it in React Native?

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Release： 2023-08-24 18:01:08

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ScrollView is a scrolling container that can accommodate multiple components and views. It is one of the core components in React Native and uses it to achieve vertical and horizontal scrolling.

ScrollView will be mapped to the corresponding native component according to the running platform. So on Android, the view maps to , on iOS to , and in a web environment to

Example 1: Vertical scrolling using ScrollView

In this example, the ScrollView contains a View and a Text component, and they are wrapped in a View.

To use ScrollView, you first need to import the component −

import { Text, View, StyleSheet, ScrollView} from &#39;react-native&#39;;

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The data to be displayed in ScrollView is stored in the names of the state object, as shown below −

state = {
   names: [
      {&#39;name&#39;: &#39;Ben&#39;, &#39;id&#39;: 1},
      {&#39;name&#39;: &#39;Susan&#39;, &#39;id&#39;: 2},
      {&#39;name&#39;: &#39;Robert&#39;, &#39;id&#39;: 3},
      {&#39;name&#39;: &#39;Mary&#39;, &#39;id&#39;: 4},
      {&#39;name&#39;: &#39;Daniel&#39;, &#39;id&#39;: 5},
      {&#39;name&#39;: &#39;Laura&#39;, &#39;id&#39;: 6},
      {&#39;name&#39;: &#39;John&#39;, &#39;id&#39;: 7},
      {&#39;name&#39;: &#39;Debra&#39;, &#39;id&#39;: 8},
      {&#39;name&#39;: &#39;Aron&#39;, &#39;id&#39;: 9},
      {&#39;name&#39;: &#39;Ann&#39;, &#39;id&#39;: 10},
      {&#39;name&#39;: &#39;Steve&#39;, &#39;id&#39;: 11},
      {&#39;name&#39;: &#39;Olivia&#39;, &#39;id&#39;: 12}
   ]
}

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The data i.e this.state.names is an array. The map() method is used on the array and the name is displayed inside View->Text Component as shown below −

<ScrollView>
   {this.state.names.map((item, index) => (<View key = {item.id} style = {styles.item}><Text>{item.name}</Text></View>))
}
</ScrollView>

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ScrollView works best for static data which is of small size.But if you want to work around with dynamic that can be a huge list best to make use of the FlatList component.

Here is the full code for ScrollView.

import React, { Component } from "react";
import { Text, View, StyleSheet, ScrollView} from &#39;react-native&#39;;
class ScrollViewExample extends Component {
   state = {
      names: [
         {'name': 'Ben', 'id': 1},
         {'name': 'Susan', 'id': 2},
         {'name': 'Robert', 'id': 3},
         {'name': 'Mary', 'id': 4},
         {'name': 'Daniel', 'id': 5},
         {'name': 'Laura', 'id': 6},
         {'name': 'John', 'id': 7},
         {'name': 'Debra', 'id': 8},
         {'name': 'Aron', 'id': 9},
         {'name': 'Ann', 'id': 10},
         {'name': 'Steve', 'id': 11},
         {'name': 'Olivia', 'id': 12}
      ]
   }
   render(props) {
      return (
         
            
               {this.state.names.map((item, index) => ({item.name}))
            }
            
         
      );
   }
}
export default ScrollViewExample;
const styles = StyleSheet.create ({
   item: {
      flexDirection: 'row',
      justifyContent: 'space-between',
      alignItems: 'center',
      padding: 30,
      margin: 2,
      borderColor: '#2a4944',
      borderWidth: 1,
      backgroundColor: '#d2f7f1'
   }
})

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Output

ScrollView组件是什么，如何在React Native中使用它？

Example 2: Horizontal scrolling using ScrollView

By default, ScrollView displays data vertically . To display the data horizontally, use the following attribute

horizontal={true} as shown below −

<ScrollView horizontal={true}>
   {this.state.names.map((item, index) => (<View key = {item.id} style = {styles.item}><Text>{item.name}</Text></View>))
}
</ScrollView>

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import React, { Component } from "react";
import { Text, View, StyleSheet, ScrollView} from &#39;react-native&#39;;
class ScrollViewExample extends Component {
   state = {
      names: [
         {'name': 'Ben', 'id': 1},
         {'name': 'Susan', 'id': 2},
         {'name': 'Robert', 'id': 3},
         {'name': 'Mary', 'id': 4},
         {'name': 'Daniel', 'id': 5},
         {'name': 'Laura', 'id': 6},
         {'name': 'John', 'id': 7},
         {'name': 'Debra', 'id': 8},
         {'name': 'Aron', 'id': 9},
         {'name': 'Ann', 'id': 10},
         {'name': 'Steve', 'id': 11},
         {'name': 'Olivia', 'id': 12}
      ]
   }
   render(props) {
      return (
            
            
               {this.state.names.map((item, index) => ({item.name}))
            }
            
         
      );
   }
}
export default ScrollViewExample;
const styles = StyleSheet.create ({
   item: {
      flexDirection: 'row',
      justifyContent: 'space-between',
      alignItems: 'center',
      padding: 30,
      margin: 2,
      borderColor: '#2a4944',
      borderWidth: 1,
      height:100,
      backgroundColor: '#d2f7f1'
   }
})

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Output

ScrollView组件是什么，如何在React Native中使用它？

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