如何在 React Native 中获取“打开前的键盘高度”？

Question

环境：

React-Native 0.60.4

问题：

我正在开发聊天应用程序。聊天有表情符号选择器。表情符号选择器必须与键盘具有相同的高度。我需要在它打开之前获得键盘的高度。我尝试使用键盘监听器，但它们在打开后会给出高度。我的最终目标是按照图片中的方式进行操作。你是怎么做到的？

示例：

import React, { useState, useEffect, createRef } from "react";
import {
  Keyboard,
  TextInput,
  View,
  EmitterSubscription,
  Button,
  KeyboardAvoidingView,
  StyleSheet
} from "react-native";

const APPROXIMATE_HEIGHT = 360;

const App = () => {
  let inputRef = createRef<TextInput>();

  const [visible, setVisible] = useState(false);
  const [height, setHeight] = useState(APPROXIMATE_HEIGHT);

  useEffect(() => {
    let keyboardDidShowListener: EmitterSubscription;

    keyboardDidShowListener = Keyboard.addListener(
      "keyboardDidShow",
      keyboardDidShow
    );

    return () => {
      if (keyboardDidShowListener) {
        keyboardDidShowListener.remove();
      }
    };
  });

  const keyboardDidShow = (e: any) => {
    setVisible(false);
    setHeight(e.endCoordinates.height); // sets the height after opening the keyboard
  };

  const openEmojiPicker = () => {
    Keyboard.dismiss();
    setVisible(true);
  };

  const openKeyboard = () => {
    setVisible(false);
    inputRef.current!.focus();
  };

  return (
    <KeyboardAvoidingView style={styles.container} behavior="height" enabled>
      <View style={styles.inputToolBar}>
        <Button
          title={visible ? "Open keyboard" : "Open emoji picker"}
          onPress={visible ? openKeyboard : openEmojiPicker}
        />
        <TextInput placeholder="test" ref={inputRef} />
      </View>
      <View style={[styles.emojiPicker, { height: visible ? height : 0 }]} />
    </KeyboardAvoidingView>
  );
};

const styles = StyleSheet.create({
  container: {
    flex: 1,
    position: "absolute",
    bottom: 0,
    left: 0,
    right: 0
  },
  inputToolBar: {
    flexDirection: "row"
  },
  emojiPicker: {
    backgroundColor: "red"
  }
});

export default App;

Answer 1

我不知道一个非常干净的方法来做到这一点，但你可以显示键盘，获取高度，然后用你的视图替换键盘。