如何在ReactJS中获得视口高度?在正常的JavaScript中使用

window.innerHeight()

但是使用ReactJS,我不确定如何获得这些信息。我的理解是

ReactDOM.findDomNode()

仅适用于已创建的组件。然而,对于文档或body元素,情况并非如此,它们可以为我提供窗口的高度。


当前回答

使用钩子(React 16.8.0+)

创建一个useWindowDimensions钩子。

import { useState, useEffect } from 'react';

function getWindowDimensions() {
  const { innerWidth: width, innerHeight: height } = window;
  return {
    width,
    height
  };
}

export default function useWindowDimensions() {
  const [windowDimensions, setWindowDimensions] = useState(getWindowDimensions());

  useEffect(() => {
    function handleResize() {
      setWindowDimensions(getWindowDimensions());
    }

    window.addEventListener('resize', handleResize);
    return () => window.removeEventListener('resize', handleResize);
  }, []);

  return windowDimensions;
}

之后你就可以像这样在元件中使用它了

const Component = () => {
  const { height, width } = useWindowDimensions();

  return (
    <div>
      width: {width} ~ height: {height}
    </div>
  );
}

工作示例

原来的答案

在React中也是一样的,你可以使用window。innerHeight来获取当前视口的高度。

正如你在这里看到的

其他回答

这个答案与Jabran Saeed的类似,除了它也处理窗口大小的调整。接下来交给我吧。

constructor(props) {
  super(props);
  this.state = { width: 0, height: 0 };
  this.updateWindowDimensions = this.updateWindowDimensions.bind(this);
}

componentDidMount() {
  this.updateWindowDimensions();
  window.addEventListener('resize', this.updateWindowDimensions);
}

componentWillUnmount() {
  window.removeEventListener('resize', this.updateWindowDimensions);
}

updateWindowDimensions() {
  this.setState({ width: window.innerWidth, height: window.innerHeight });
}

我建议使用useSyncExternalStore

import { useSyncExternalStore } from "react";

const store = {
  size: {
    height: undefined,
    width: undefined
  }
};

export default function ChatIndicator() {
  const { height, width } = useSyncExternalStore(subscribe, getSnapshot);
  return (
    <h1>
      {width} {height}
    </h1>
  );
}

function getSnapshot() {
  if (
    store.size.height !== window.innerHeight ||
    store.size.width !== window.innerWidth
  ) {
    store.size = { height: window.innerHeight, width: window.innerWidth };
  }
  return store.size;
}

function subscribe(callback) {
  window.addEventListener("resize", callback);
  return () => {
    window.removeEventListener("resize", callback);
  };
}

如果你想试试:https://codesandbox.io/s/vibrant-antonelli-5cecpm

@speckledcarp和@Jamesl的回答都很精彩。然而,在我的例子中,我需要一个组件,其高度可以扩展整个窗口高度,在呈现时有条件....但是在render()中调用HOC会重新渲染整个子树。很糟糕。

另外,我对获取作为道具的值不感兴趣,但只是想要一个父div,将占据整个屏幕的高度(或宽度,或两者)。

所以我写了一个父组件,提供了一个完整的高度(和/或宽度)div。

一个用例:

class MyPage extends React.Component {
  render() {
    const { data, ...rest } = this.props

    return data ? (
      // My app uses templates which misbehave badly if you manually mess around with the container height, so leave the height alone here.
      <div>Yay! render a page with some data. </div>
    ) : (
      <FullArea vertical>
        // You're now in a full height div, so containers will vertically justify properly
        <GridContainer justify="center" alignItems="center" style={{ height: "inherit" }}>
          <GridItem xs={12} sm={6}>
            Page loading!
          </GridItem>
        </GridContainer>
      </FullArea>
    )

下面是这个组件:

import React, { Component } from 'react'
import PropTypes from 'prop-types'

class FullArea extends Component {
  constructor(props) {
    super(props)
    this.state = {
      width: 0,
      height: 0,
    }
    this.getStyles = this.getStyles.bind(this)
    this.updateWindowDimensions = this.updateWindowDimensions.bind(this)
  }

  componentDidMount() {
    this.updateWindowDimensions()
    window.addEventListener('resize', this.updateWindowDimensions)
  }

  componentWillUnmount() {
    window.removeEventListener('resize', this.updateWindowDimensions)
  }

  getStyles(vertical, horizontal) {
    const styles = {}
    if (vertical) {
      styles.height = `${this.state.height}px`
    }
    if (horizontal) {
      styles.width = `${this.state.width}px`
    }
    return styles
  }

  updateWindowDimensions() {
    this.setState({ width: window.innerWidth, height: window.innerHeight })
  }

  render() {
    const { vertical, horizontal } = this.props
    return (
      <div style={this.getStyles(vertical, horizontal)} >
        {this.props.children}
      </div>
    )
  }
}

FullArea.defaultProps = {
  horizontal: false,
  vertical: false,
}

FullArea.propTypes = {
  horizontal: PropTypes.bool,
  vertical: PropTypes.bool,
}

export default FullArea

我发现了一个简单的组合QoP和speckledcarp的答案,使用React Hooks和调整大小功能,代码行数略少:

const [width, setWidth]   = useState(window.innerWidth);
const [height, setHeight] = useState(window.innerHeight);
const updateDimensions = () => {
    setWidth(window.innerWidth);
    setHeight(window.innerHeight);
}
useEffect(() => {
    window.addEventListener("resize", updateDimensions);
    return () => window.removeEventListener("resize", updateDimensions);
}, []);

哦,是的,确保resize事件是双引号,而不是单引号。这一点让我有点不安;)

我刚刚编辑了QoP当前的答案以支持SSR,并将其与Next.js (React 16.8.0+)一起使用:

/钩/ useWindowDimensions.js:

import { useState, useEffect } from 'react';

export default function useWindowDimensions() {

  const hasWindow = typeof window !== 'undefined';

  function getWindowDimensions() {
    const width = hasWindow ? window.innerWidth : null;
    const height = hasWindow ? window.innerHeight : null;
    return {
      width,
      height,
    };
  }

  const [windowDimensions, setWindowDimensions] = useState(getWindowDimensions());

  useEffect(() => {
    if (hasWindow) {
      function handleResize() {
        setWindowDimensions(getWindowDimensions());
      }

      window.addEventListener('resize', handleResize);
      return () => window.removeEventListener('resize', handleResize);
    }
  }, [hasWindow]);

  return windowDimensions;
}

/ yourComponent.js:

import useWindowDimensions from './hooks/useWindowDimensions';

const Component = () => {
  const { height, width } = useWindowDimensions();
  /* you can also use default values or alias to use only one prop: */
  // const { height: windowHeight = 480 } useWindowDimensions();

  return (
    <div>
      width: {width} ~ height: {height}
    </div>
  );
}