Question

我正试图添加一个点心栏，以便无论用户是否登录都显示一条消息。 SnackBar.jsx：

import React from "react";
import PropTypes from "prop-types";
import classNames from "classnames";
import CheckCircleIcon from "@material-ui/icons/CheckCircle";
import ErrorIcon from "@material-ui/icons/Error";
import CloseIcon from "@material-ui/icons/Close";
import green from "@material-ui/core/colors/green";
import IconButton from "@material-ui/core/IconButton";
import Snackbar from "@material-ui/core/Snackbar";
import SnackbarContent from "@material-ui/core/SnackbarContent";
import { withStyles } from "@material-ui/core/styles";

const variantIcon = {
  success: CheckCircleIcon,
  error: ErrorIcon
};

const styles1 = theme => ({
  success: {
    backgroundColor: green[600]
  },
  error: {
    backgroundColor: theme.palette.error.dark
  },
  icon: {
    fontSize: 20
  },
  iconVariant: {
    opacity: 0.9,
    marginRight: theme.spacing.unit
  },
  message: {
    display: "flex",
    alignItems: "center"
  }
});

function SnackbarContentWrapper(props) {
  const { classes, className, message, onClose, variant, ...other } = props;
  const Icon = variantIcon[variant];

  return (
    <SnackbarContent
      className={classNames(classes[variant], className)}
      aria-describedby="client-snackbar"
      message={(
        <span className={classes.message}>
          <Icon className={classNames(classes.icon, classes.iconVariant)} />
          {message}
        </span>
      )}
      action={[
        <IconButton
          key="close"
          aria-label="Close"
          color="inherit"
          className={classes.close}
          onClick={onClose}
        >
          <CloseIcon className={classes.icon} />
        </IconButton>
      ]}
      {...other}
    />
  );
}

SnackbarContentWrapper.propTypes = {
  classes: PropTypes.shape({
    success: PropTypes.string,
    error: PropTypes.string,
    icon: PropTypes.string,
    iconVariant: PropTypes.string,
    message: PropTypes.string,
  }).isRequired,
  className: PropTypes.string.isRequired,
  message: PropTypes.node.isRequired,
  onClose: PropTypes.func.isRequired,
  variant: PropTypes.oneOf(["success", "error"]).isRequired
};

const MySnackbarContentWrapper = withStyles(styles1)(SnackbarContentWrapper);

const CustomizedSnackbar = ({
  open,
  handleClose,
  variant,
  message
}) => {
  return (
    <div>
      <Snackbar
        anchorOrigin={{
          vertical: "bottom",
          horizontal: "left"
        }}
        open={open}
        autoHideDuration={6000}
        onClose={handleClose}
      >
        <MySnackbarContentWrapper
          onClose={handleClose}
          variant={variant}
          message={message}
        />
      </Snackbar>
    </div>
  );
};

CustomizedSnackbar.propTypes = {
  open: PropTypes.bool.isRequired,
  handleClose: PropTypes.func.isRequired,
  variant: PropTypes.string.isRequired,
  message: PropTypes.string.isRequired
};

export default CustomizedSnackbar;

SignInFormContainer.jsx：

import React, { useState } from 'react';
import PropTypes from 'prop-types';
import { connect } from 'react-redux';
import SnackBar from '../../components/SnackBar';
import SignInForm from './SignInForm';

const SingInContainer = ({ message, variant}) => {
    const [open, setSnackBarState] = useState(false);
    const handleClose = (reason) => {
        if (reason === 'clickaway') {
          return;
        }
        setSnackBarState(false)

      };

    if (variant) {
        setSnackBarState(true);
    }
    return (
        <div>
        <SnackBar
            open={open}
            handleClose={handleClose}
            variant={variant}
            message={message}
            />
        <SignInForm/>
        </div>
    )
}

SingInContainer.propTypes = {
    variant: PropTypes.string.isRequired,
    message: PropTypes.string.isRequired
}

const mapStateToProps = (state) => {
    const {variant, message } = state.snackBar;

    return {
        variant,
        message
    }
}

export default connect(mapStateToProps)(SingInContainer);

运行应用程序时出现此错误：

Invariant Violation: Too many re-renders. React limits the number of renders to prevent an infinite loop.
at invariant (http://localhost:9000/bundle.js:34484:15)
at dispatchAction (http://localhost:9000/bundle.js:47879:44)
at SingInContainer (http://localhost:9000/bundle.js:79135:5)
at renderWithHooks (http://localhost:9000/bundle.js:47343:18)
at updateFunctionComponent (http://localhost:9000/bundle.js:49010:20)
at beginWork (http://localhost:9000/bundle.js:50020:16)
at performUnitOfWork (http://localhost:9000/bundle.js:53695:12)
at workLoop (http://localhost:9000/bundle.js:53735:24)
at HTMLUnknownElement.callCallback (http://localhost:9000/bundle.js:34578:14)
at Object.invokeGuardedCallbackDev (http://localhost:9000/bundle.js:34628:16)

该问题归因于SnackBar组件。我使用useState钩子来更改SnackBar的状态。我是否应该使用一个类和一个componentShouldUpdate才能不进行多次渲染？

Answer 1

我怀疑问题在于您正在立即在函数组件体内调用状态设置器，这迫使React使用相同的道具再次再次调用您的函数，最终导致再次调用状态设置器，这会触发React再次调用您的函数。...等等。

const SingInContainer = ({ message, variant}) => {
    const [open, setSnackBarState] = useState(false);
    const handleClose = (reason) => {
        if (reason === 'clickaway') {
          return;
        }
        setSnackBarState(false)

      };

    if (variant) {
        setSnackBarState(true); // HERE BE DRAGONS
    }
    return (
        <div>
        <SnackBar
            open={open}
            handleClose={handleClose}
            variant={variant}
            message={message}
            />
        <SignInForm/>
        </div>
    )
}

相反，我建议您仅使用三元有条件地设置state属性的默认值，所以最终得到：

const SingInContainer = ({ message, variant}) => {
    const [open, setSnackBarState] = useState(variant ? true : false); 
                                  // or useState(!!variant); 
                                  // or useState(Boolean(variant));
    const handleClose = (reason) => {
        if (reason === 'clickaway') {
          return;
        }
        setSnackBarState(false)

      };

    return (
        <div>
        <SnackBar
            open={open}
            handleClose={handleClose}
            variant={variant}
            message={message}
            />
        <SignInForm/>
        </div>
    )
}

综合演示

请参阅此CodeSandbox.io demo，以获取有关其工作原理的全面演示，以及已损坏的组件，您可以在两者之间进行切换。

Answer 2

我也有同样的问题，解决方案是我没有在onClick中绑定事件。因此，当它第一次呈现并且数据更多时，最终又再次调用状态设置器，从而触发React再次调用您的函数，依此类推。

export default function Component(props) {

function clickEvent (event, variable){
    console.log(variable);
}

return (
    <div>
        <IconButton
            key="close"
            aria-label="Close"
            color="inherit"
            onClick={e => clickEvent(e, 10)} // or you can call like this:onClick={() => clickEvent(10)} 
        >
    </div>
)
}

Answer 3

您必须在onClick中链接事件。此外，单击功能必须接收事件。参见示例

file_size

Answer 4

您需要添加一个事件，然后再像这样调用handleFunction：

function SingInContainer() {
..
..
handleClose = () => {
}

return (
    <SnackBar
        open={open}
        handleClose={() => handleClose}
        variant={variant}
        message={message}
        />
    <SignInForm/>
)

}

Answer 5

你可以通过在函数内部使用钩子来防止这个错误

Answer 6

在SnackbarContentWrapper中，您需要更改

<IconButton
          key="close"
          aria-label="Close"
          color="inherit"
          className={classes.close}
          onClick={onClose}
        >

到

<IconButton
          key="close"
          aria-label="Close"
          color="inherit"
          className={classes.close}
          onClick={() => onClose}
        >

，以便仅在您单击时触发操作。

相反，您可以咖喱handleClose中的SingInContainer到

const handleClose = () => (reason) => {
        if (reason === 'clickaway') {
          return;
        }
        setSnackBarState(false)

      };

是一样的

未捕获的不变违规：重新渲染过多。 React限制渲染次数以防止无限循环

6 个答案:

综合演示