javascript – 如何使用react-native的TextInput的`selectionState`道具？

我正在构建一个反应原生的应用程序.我有一个< TextInput>,当出现问题时,我希望引起< TextInput>变得专注. < TextInput>上唯一记录的方法实例是.isFocused()和.clear() – 看起来都不像我在寻找.我显然想要.focus().

我发现这个仅限iOS的selectedState道具似乎提供了我正在寻找的东西. The docs说：

iOS selectionState DocumentSelectionState

An instance of DocumentSelectionState,this is some state that is responsible for maintaining selection information for a document.

Some functionality that can be performed with this instance is:

blur()

focus()

update()

You can reference DocumentSelectionState in vendor/document/selection/DocumentSelectionState.js

我不清楚如何运用这个道具,我没有在网上找到任何例子.在doc页面上发布的冗长示例代码不使用它.

有人能告诉我这可能是什么样子吗？这是我最好的猜测：
import React,{
    Component
} from 'react';
import {
    // the "DocumentSelectionState.js" file mentioned in the docs
    // lives inside react-native,so hopefully it's exported 
    DocumentSelectionState,TextInput,TouchableHighlight,View
} from 'react-native';
import Styles from './style';

export default class Scene extends Component {

    constructor(props) {
        super(props);

        // get my hands on "An instance of DocumentSelectionState"
        // which I can pass to the TextInput,and whose .focus()
        // method I can call
        this.text1DSS = new DocumentSelectionState();
    }

    render() {
        return (
            
不幸的是,该代码将无法运行： undefined is not a constructor (evaluating ‘new _reactNative.DocumentSelectionState()’) 我认为这意味着react-native不会导出DocumentSelectionState成员(或者至少我的版本不是：0.23,仍然是documents the prop). 我无法弄清楚如何在vanilla RN设置中访问DocumentSelectionState,所以我无法真正测试我的理论. 谁有人在这里工作？


最佳答案
我能够访问.focus()方法的唯一方法是通过this.refs
您的代码看起来像：

import React,{ Component } from 'react';
import { TextInput,View } from 'react-native';
import Styles from './style';

export default class Scene extends Component {


    render() {
         return (
            

希望有所帮助

iosios

javascript – 如何使用react-native的TextInput的`selectionState`道具？

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