React类如何锚定Popover

Question

[嗨，我是React和Hooks的新手，就像useState一样。我很难理解这个概念以及如何使用它。因此，我不想制作比我更复杂的作品和文件。

我遇到了将React.component从函数切换到类Popover的问题。

我分叉了CodeSandbox以尝试显示我也想切换的内容。但是，我只是不太了解文档以使其实现。

[具有React.Class.Component使用React-States需要发生什么？

这里是sandbox link

Answer 1

    import React, { Component } from "react";
import { makeStyles } from "@material-ui/core/styles";
import Popover from "@material-ui/core/Popover";
import Typography from "@material-ui/core/Typography";
import Button from "@material-ui/core/Button";

// const useStyles = makeStyles(theme => ({
//   typography: {
//     padding: theme.spacing(2)
//   }
// }));

export default class SimplePopover extends Component {
  constructor(props) {
    super(props);
    // const classes = useStyles();
    // const [anchorEl, setAnchorEl] = React.useState(null);
    this.state = {
      anchorEl: null,
      open: false,
      id: undefined
    }
    this.handleClick = this.handleClick.bind(this);
    this.handleClose = this.handleClose.bind(this);

    // const open = Boolean(anchorEl);
    // const id = open ? "simple-popover" : undefined;
  }

  handleClick(event) {
    this.setState({anchorEl: event.currentTarget, open: Boolean(event.currentTarget), id: "simple-popover"});
  }

  handleClose(event) {
    this.setState({anchorEl: event.currentTarget, open: false, id: undefined});
  }

  render() {
    return (
      <div>
        <Button
          aria-describedby={this.id}
          variant="contained"
          color="primary"
          onClick={this.handleClick}
        >
          Open Popover
        </Button>
        <Popover
          id={this.id}
          open={this.state.open}
          anchorEl={this.state.anchorEl}
          onClose={this.handleClose}
          anchorOrigin={{
            vertical: "bottom",
            horizontal: "center"
          }}
          transformOrigin={{
            vertical: "top",
            horizontal: "center"
          }}
        >
          {/* <Typography className={this.classes.typography}> */}
          <div>The content of the Popover.</div>
          {/* </Typography> */}
        </Popover>
      </div>
    );
  }
}

错误

const [anchorEl, setAnchorEl] = React.useState(null);

您不能在类组件内部使用挂钩