Material UI this.state 彩色背景错误

Question

我的眼睛受伤了，我试图让滑块不仅可以改变按钮的半径，还可以改变颜色。

这 sandbox 成功更新了半径。

Here is the code:
import React from "react";
import { makeStyles } from "@material-ui/core/styles";
import Grid from "@material-ui/core/Grid";
import Slider from "@material-ui/core/Slider";
import Input from "@material-ui/core/Input";
import Button from "@material-ui/core/Button";
import reactCSS from "reactcss";
import { SketchPicker } from "react-color";

const useStyles = makeStyles((theme) => ({
  root: {
    "& > *": {
      margin: theme.spacing(1)
    }
  },
  Button: {
    width: 150,
    height: 50,
    borderRadius: "var(--borderRadius)"
  }
}));

export default function InputSlider() {
  const classes = useStyles();
  const [value, setValue] = React.useState(30);
  const handleSliderChange = (event, newValue) => {
    setValue(newValue);
  };
  const handleInputChange = (event) => {
    setValue(event.target.value === "" ? "" : Number(event.target.value));
  };
  const handleBlur = () => {
    if (value < 0) {
      setValue(0);
    } else if (value > 30) {
      setValue(30);
    }
  };
  return (
    <div className={classes.root}>
      <style>
        {`:root {
          --borderRadius = ${value}px;
        }`}
      </style>
      <Button
        style={{ borderRadius: value }}
        variant="contained"
        color="primary"
        value="value"
        onChange={handleSliderChange}
        className={classes.Button}
      >
        Fire laser
      </Button>
      <Grid container spacing={2}>
        <Grid item xs>
          <Slider
            value={typeof value === "number" ? value : 0}
            onChange={handleSliderChange}
            aria-labelledby="input-slider"
          />
        </Grid>
        <Grid item>
          <Input
            value={value}
            margin="dense"
            onChange={handleInputChange}
            onBlur={handleBlur}
            inputProps={{
              step: 10,
              min: 0,
              max: 24,
              type: "number"
            }}
          />
        </Grid>
      </Grid>
    </div>
  );
}

现在我正在研究如何使用 color picker 更改按钮的背景颜色，最终还会更改字体颜色。

我收到 this.state 的错误消息。有什么建议？

这是一个正在进行中的不同沙箱，并且有错误消息 - https://codesandbox.io/s/material-demo-forked-l35qy?file=/demo.js

这是带有错误消息的代码：

import React from "react";
import { makeStyles } from "@material-ui/core/styles";
import Grid from "@material-ui/core/Grid";
import Slider from "@material-ui/core/Slider";
import Input from "@material-ui/core/Input";
import Button from "@material-ui/core/Button";
import reactCSS from "reactcss";
import { SketchPicker } from "react-color";

const useStyles = makeStyles((theme) => ({
  root: {
    "& > *": {
      margin: theme.spacing(1)
    }
  },
  Button: {
    width: 150,
    height: 50,
    borderRadius: "var(--borderRadius)",
    background: `rgba(${this.state.color.r}, ${this.state.color.g}, ${this.state.color.b}, ${this.state.color.a})`
  },
  color: {
    width: "36px",
    height: "14px",
    borderRadius: "2px",
    background: `rgba(${this.state.color.r}, ${this.state.color.g}, ${this.state.color.b}, ${this.state.color.a})`
  },
  swatch: {
    padding: "5px",
    background: "#fff",
    borderRadius: "1px",
    display: "inline-block",
    cursor: "pointer"
  },
  popover: {
    position: "absolute",
    zIndex: "2"
  },
  cover: {
    position: "fixed",
    top: "0px",
    right: "0px",
    bottom: "0px",
    left: "0px"
  }
}));

export default function InputSlider() {
  const classes = useStyles();
  const [value, setValue] = React.useState(30);
  const handleSliderChange = (event, newValue) => {
    setValue(newValue);
  };
  const handleInputChange = (event) => {
    setValue(event.target.value === "" ? "" : Number(event.target.value));
  };
  const handleBlur = () => {
    if (value < 0) {
      setValue(0);
    } else if (value > 30) {
      setValue(30);
    }
  };
  const handleClick = () => {
    this.setState({ displayColorPicker: !this.state.displayColorPicker });
  };

  const handleClose = () => {
    this.setState({ displayColorPicker: false });
  };

  const handleChange = (color) => {
    this.setState({ color: color.rgb });
  };
  return (
    <div className={classes.root}>
      <style>
        {`:root {
          --borderRadius = ${value}px;
        }`}
      </style>
      <Button
        style={{ borderRadius: value }}
        variant="contained"
        color="primary"
        value="value"
        onChange={handleSliderChange}
        className={classes.Button}
      >
        Fire laser
      </Button>
      <Grid container spacing={2}>
        <Grid item xs>
          <Slider
            value={typeof value === "number" ? value : 0}
            onChange={handleSliderChange}
            aria-labelledby="input-slider"
          />
        </Grid>
        <Grid item>
          <Input
            value={value}
            margin="dense"
            onChange={handleInputChange}
            onBlur={handleBlur}
            inputProps={{
              step: 10,
              min: 0,
              max: 24,
              type: "number"
            }}
          />
        </Grid>
      </Grid>
      <div>
        <Button style={useStyles.color}></Button>

        <div style={useStyles.swatch} onClick={this.handleClick}>
          <div style={useStyles.color} />
        </div>
        {this.state.displayColorPicker ? (
          <div style={useStyles.popover}>
            <div style={useStyles.cover} onClick={this.handleClose} />
            <SketchPicker
              color={this.state.color}
              onChange={this.handleChange}
            />
          </div>
        ) : null}
      </div>
    </div>
  );
}

Answer 1

您不能在 useStyles 中使用状态，因为您只能访问主题，而不能访问任何道具。您应该改用 makeStyles 调用，因为它至少可以让您传入一些道具。这已经在这里得到回答，并且有一个很好的例子。

另一个问题是您使用的是基于功能的组件，其中状态的编写方式不同。我已经使用 useState 钩子为您重写了它，所以希望这至少能得到要使用的颜色。

export default function InputSlider() {
  const classes = useStyles();
  const [value, setValue] = React.useState(30);
  const [color, setColor] = React.useState({ background: "#fff" });

  const handleSliderChange = (event, newValue) => {
    setValue(newValue);
  };
  const handleInputChange = (event) => {
    setValue(event.target.value === "" ? "" : Number(event.target.value));
  };
  const handleBlur = () => {
    if (value < 0) {
      setValue(0);
    } else if (value > 30) {
      setValue(30);
    }
  };
  const handleClick = (color) => {
    setColor(color);
  };

  const handleClose = () => {
    setColor({ displayColorPicker: false });
  };

  const handleChange = (color) => {
    setColor(color);
  };
  return (
    <div className={classes.root}>
      <style>
        {`:root {
          --borderRadius = ${value}px;
        }`}
      </style>
      <Button
        style={{ borderRadius: value }}
        variant="contained"
        color="primary"
        value="value"
        onChange={handleSliderChange}
        className={classes.Button}
      >
        Fire laser
      </Button>
      <Grid container spacing={2}>
        <Grid item xs>
          <Slider
            value={typeof value === "number" ? value : 0}
            onChange={handleSliderChange}
            aria-labelledby="input-slider"
          />
        </Grid>
        <Grid item>
          <Input
            value={value}
            margin="dense"
            onChange={handleInputChange}
            onBlur={handleBlur}
            inputProps={{
              step: 10,
              min: 0,
              max: 24,
              type: "number"
            }}
          />
        </Grid>
      </Grid>
      <div>
        <Button style={useStyles.color}></Button>

        <div style={useStyles.swatch} onClick={handleClick}>
          <div style={useStyles.color} />
        </div>
        {color ? (
          <div style={useStyles.popover}>
            <div style={useStyles.cover} onClick={handleClose} />
            <SketchPicker color={color} onChange={handleChange} />
          </div>
        ) : null}
      </div>
    </div>
  );
}

Answer 2

@RichardHpa 是正确的，您无法访问 makeStyles 中的状态，并且您混淆了 class 组件和功能组件。在你的情况下，你应该一直使用 useState()。

您已经有了如何设置边框半径的示例，因此您可以复制该流程以在背景颜色中使用它，直接在 Button 上设置样式。

这是代码框：

https://codesandbox.io/s/material-demo-forked-djh78?file=/demo.js

<Button
    style={{
        borderRadius: value,
        background: `rgba(${color.r}, ${color.g}, ${color.b}, ${color.a})`

        // may need another color picker for text coloe. otherwise, bg color will be the same as text color.
        // color: `rgba(${color.r}, ${color.g}, ${color.b}, ${color.a})`
    }}
    variant="contained"
    color="primary"
    value="value"
    onChange={handleSliderChange}
    className={classes.Button}
>

无需为我评分，@RichardHpa 值得称赞。

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