尝试将 :focus 样式应用于样式化组件内的嵌套 SVG

Question

我有一个简单的搜索栏 React 组件。

该组件是一个 <div> 包装一个 <input> 元素和一个 <svg> 并通过样式组件应用样式。我已经阅读了有关 Styled Components 的文档，但在这种情况下，我似乎找不到将 :focus 样式应用于嵌套子元素的方法 <svg>。

Expected behavior: The SVG should turn blue when the input is in :focus

Current behavior: The SVG color stays black no matter if the input is in :focus or not

我这里有一个 CodePen，显示 :focus 样式适用于输入，但不适用于 <svg>

还有我当前的组件：

import React, { useState } from "react";
import styled from "styled-components";

export const FilterTextbox = () => {
  const [text, setText] = useState("");
  const handleChange = (event: any) => {
    setText(event.target.value);
  };
  return (
    <StyledInput className={"inputWithIcon"}>
      <Input
        type="text"
        value={text}
        onChange={handleChange}
        placeholder="Search"
      />
      <svg
        xmlns="http://www.w3.org/2000/svg"
        viewBox="0 0 24 24"
        width="36px"
        height="36px"
      >
        <path d="M 13.261719 14.867188 L 15.742188 17.347656 C 15.363281 18.070313 15.324219 18.789063 15.722656 19.1875 L 20.25 23.714844 C 20.820313 24.285156 22.0625 23.972656 23.015625 23.015625 C 23.972656 22.058594 24.285156 20.820313 23.714844 20.25 L 19.191406 15.722656 C 18.789063 15.324219 18.070313 15.363281 17.347656 15.738281 L 14.867188 13.261719 Z M 8.5 0 C 3.804688 0 0 3.804688 0 8.5 C 0 13.195313 3.804688 17 8.5 17 C 13.195313 17 17 13.195313 17 8.5 C 17 3.804688 13.195313 0 8.5 0 Z M 8.5 15 C 4.910156 15 2 12.089844 2 8.5 C 2 4.910156 4.910156 2 8.5 2 C 12.089844 2 15 4.910156 15 8.5 C 15 12.089844 12.089844 15 8.5 15 Z" />
      </svg>
    </StyledInput>
  );
};

const Input = styled.input`
  height: 50px;
  width: 100%;
  border: 2px solid #aaa;
  border-radius: 4px;
  margin: 8px 0;
  outline: none;
  padding: 8px;
  box-sizing: border-box;
  transition: 0.3s;
  padding-left: 50px;
  font-size: 25px;
  :focus {
    border-color: dodgerBlue;
    box-shadow: 0 0 8px 0 dodgerBlue;
  }
`;

const StyledInput = styled.div`
  svg {
    position: absolute;
    left: 0;
    top: 8px;
    padding: 9px 8px;
    color: black;
    transition: 0.3s;
    :focus {
      color: dodgerBlue;
    }
  }

  /* &svg:focus {
    color: dodgerBlue;
  } */

  &.inputWithIcon {
    position: relative;
  }
`;

Answer 1

是input 引起了关注，所以样式规则应该包含input:focus。

当输入具有焦点时，此 CSS 规则将针对 svg：

input:focus + svg {
  /* styling goes here */
}

这是一个使用直接 HTML 和 CSS 的示例。

div {
  margin: 8px;
  position: relative;
}

input {
  height: 50px;
  width: 100%;
  border: 2px solid #aaa;
  border-radius: 4px;
  margin: 8px 0;
  outline: none;
  padding: 8px;
  box-sizing: border-box;
  transition: 0.3s;
  padding-left: 50px;
  font-size: 25px;
}

svg {
  position: absolute;
  left: 0;
  top: 8px;
  padding: 9px 8px;
  color: black;
  transition: 0.3s;
}

input:focus {
  border-color: dodgerBlue;
  box-shadow: 0 0 8px 0 dodgerBlue;
}

input:focus+svg {
  fill: dodgerBlue;
}

<div>
  <input>
  <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" width="36px" height="36px">
        <path d="M 13.261719 14.867188 L 15.742188 17.347656 C 15.363281 18.070313 15.324219 18.789063 15.722656 19.1875 L 20.25 23.714844 C 20.820313 24.285156 22.0625 23.972656 23.015625 23.015625 C 23.972656 22.058594 24.285156 20.820313 23.714844 20.25 L 19.191406 15.722656 C 18.789063 15.324219 18.070313 15.363281 17.347656 15.738281 L 14.867188 13.261719 Z M 8.5 0 C 3.804688 0 0 3.804688 0 8.5 C 0 13.195313 3.804688 17 8.5 17 C 13.195313 17 17 13.195313 17 8.5 C 17 3.804688 13.195313 0 8.5 0 Z M 8.5 15 C 4.910156 15 2 12.089844 2 8.5 C 2 4.910156 4.910156 2 8.5 2 C 12.089844 2 15 4.910156 15 8.5 C 15 12.089844 12.089844 15 8.5 15 Z" />
  </svg>
</div>