当 src 更改时，React img 不会立即更改。 我怎样才能解决这个问题？

Question

I have a basic <img> with a src.

<img src={src} />

If I change the src from say /1.jpg to /2.jpg and the new image takes 1 second to load, React will continue to show /1.jpg until the new image is loaded.

What I want is for the old image to be discarded while the new image is being loaded. (eg display: none)

Any idea how to accomplish this? Ideally without conditional rendering, because I still need to use onLoad and onError

EDIT: Here's some more code. It's a little more complicated than my question, but I'm just trying to add some loading and error state to the image.

I have a button that calls this onClick

this.props.history.push('/${page + 1}');

This is the image component, where src is based on the page from the URL.

import React, { Component } from 'react';
import CenteredLoading from 'components/loading/CenteredLoading';

type Props = { src: string };

type State = {
  status: 'LOADING' | 'LOADED' | 'FAILED',
};

class ImageWithLoader extends Component<Props, State> {
  state = {
    status: 'LOADING',
  };

  handleImageLoad = () => {
    this.setState({ status: 'LOADED' });
    console.error('image loaded');
  };

  handleImageError = () => {
    this.setState({ status: 'FAILED' });
    console.error('image error');
  };

  render() {
    const { src, ...otherProps } = this.props;
    const { status } = this.state;

    return (
      <React.Fragment>
        <img
        {...otherProps}
        onLoad={this.handleImageLoad}
        onError={this.handleImageError}
        src={src}
        />

        {status === 'LOADING' && <CenteredLoading />}
        {status === 'FAILED' && <p>error</p>}
      </React.Fragment>
    );
  }
}

export default ImageWithLoader;

Answer 1

只需将关键属性添加到您的图像标签，并为图像源等关键属性分配一些唯一值。

<img src={image_source} key={image_source}></img>

Answer 2

Made my own workaround.

I believe because react isn't mounting a new component (ie <img> ), it's not going to update to the new image until it's finished loading.

What I did was check if the src changed in componentDidUpdate and change the status to LOADING . Then I set img style to display: none while its status was LOADING .

EDIT: Also, by manually setting my own key, I can force React to re-render the <img>