ScrollView组件是什么，如何在React Native中使用它？

示例 1：使用 ScrollView 进行垂直滚动

在这个示例中，ScrollView 包含一个 View 和一个 Text 组件，并且它们被包裹在一个 View 中。

要使用 ScrollView，首先需要导入该组件 −

import { Text, View, StyleSheet, ScrollView} from 'react-native';

要在ScrollView中显示的数据存储在状态对象的names中，如下所示 −

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}
   ]
}

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 −

   {this.state.names.map((item, index) => ({item.name}))
}

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 'react-native';
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'
   }
})

输出

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示例2：使用ScrollView水平滚动

默认情况下，ScrollView垂直显示数据。要水平显示数据，请使用以下属性

horizontal={true} 如下所示 −

   {this.state.names.map((item, index) => ({item.name}))
}

import React, { Component } from "react";
import { Text, View, StyleSheet, ScrollView} from 'react-native';
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'
   }
})

输出