《React-Native系列》39、 ReactNative之键盘Keyboard

今天我们来说下RN对键盘事件的支持。

在react-native 的Component组件中有个Keyboard.

github地址如下： https://github.com/facebook/react-native/tree/770091f3c13f7c1bd77c50f979d89a774001fbf0/Libraries/Components/Keyboard

我们先来看下官方提供的例子，监听键盘的弹出与消失。Demo如下：

import React, { Component } from 'react';
import { Keyboard, TextInput } from 'react-native';

class Example extends Component {
  componentWillMount () {
    this.keyboardDidShowListener = Keyboard.addListener('keyboardDidShow', this._keyboardDidShow);
    this.keyboardDidHideListener = Keyboard.addListener('keyboardDidHide', this._keyboardDidHide);
  }

  componentWillUnmount () {
    this.keyboardDidShowListener.remove();
    this.keyboardDidHideListener.remove();
  }

  _keyboardDidShow () {
    alert('Keyboard Shown');
  }

  _keyboardDidHide () {
    alert('Keyboard Hidden');
  }

  render() {
    return (
      <TextInput
        onSubmitEditing={Keyboard.dismiss}
      />
    );
  }
}

Keyboard支持的监听事件如下：

@param {string} nativeEvent The `nativeEvent` is the string that identifies the event you're listening for.  This can be any of the following:
- `keyboardWillShow`
- `keyboardDidShow`
- `keyboardWillHide`
- `keyboardDidHide`
- `keyboardWillChangeFrame`
- `keyboardDidChangeFrame`

使用的时候需要测试下Android和iOS下监听的事件是否都ok。

踩坑如下：

Android 对keyboardWillShow 监听不到。

同样，我们在源码里可以找到使键盘消失的函数

  /**
   * Dismisses the active keyboard and removes focus.
   */
  dismiss () {
    dismissKeyboard();
  }

我们如果需要使用时，可以如下：

const dismissKeyboard = require('dismissKeyboard’);
dismissKeyboard();