以父组件内的对象形式从所有子组件获取合并数据：React JS

Question

我正在为一个应用程序实现一个设置页面。对于每个设置，我都实现了一个启用（绿色）或禁用（红色）状态的滑块。但是父级的设置是只读的，并且是根据其子级的值计算的。

Parent 的设置推导如下：如果所有孩子都是红色的，则父母保持红色；如果都是绿色，则父母保持绿色；如果至少有一个孩子是绿色的，那么父母会保持灰色（待定）。

这些设置按如下方式分组：

父功能 1：（只读切换）

 Setting 1   (Toggle)

 Setting 2   (Toggle)

父功能 2：（只读切换）

Setting 1   (Toggle)

Setting 2   (Toggle)

最后还有一个按钮，它为我提供了所有父母和孩子的综合价值观。但到目前为止，我只能和一个父母和两个孩子一起做。

有人可以帮助在一个地方获取所有设置的合并值（就像配置所有这些设置的超级父组件）。

为此，我将 react-multi-toggle 用于此切换开关。

非常感谢您的帮助。

代码沙盒：https://codesandbox.io/s/react-multi-toggle-solution-perfect-v9bi5

应用

import React from "react";
import ChildSwitch from "./ChildSwitch";
import ParentSwitch from "./ParentSwitch";

export default class App extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      parentVal: "disabled",
      switch1Val: "enabled",
      switch2Val: "disabled"
    };
  }

  componentDidMount() {
    this.setParentSwitchValue();
  }

  onGetChildSwitchValues = () => {
    console.log(this.state);
  };

  setChildSwitchValue = (whichSwitch, selected) => {
    this.setState(
      prevState => ({ ...prevState, [whichSwitch]: selected }),
      this.setParentSwitchValue
    );
  };

  setParentSwitchValue = () => {
    const { switch1Val, switch2Val } = this.state;
    const switchStates = [switch1Val, switch2Val];
    let parent = "pending";
    if (switchStates.every(val => val === "enabled")) {
      parent = "enabled";
    }
    if (switchStates.every(val => val === "disabled")) {
      parent = "disabled";
    }
    this.setState(prevState => ({ ...prevState, parentVal: parent }));
  };

  render() {
    const { parentVal, switch1Val, switch2Val } = this.state;
    return (
      <>
        <div className="boxed">
          Parent Setting 1 :{" "}
          <ParentSwitch
            parentSwitch={parentVal}
            onSelect={this.setParentSwitchValue}
          />
          Setting 1:
          <ChildSwitch
            switchName={"switch1Val"}
            selected={switch1Val}
            onSelect={this.setChildSwitchValue}
          />
          Setting 2:
          <ChildSwitch
            switchName={"switch2Val"}
            selected={switch2Val}
            onSelect={this.setChildSwitchValue}
          />
        </div>
        <button onClick={this.onGetChildSwitchValues}>Get All Values</button>
      </>
    );
  }
}

儿童设置

import MultiToggle from "react-multi-toggle";
import React from "react";

export default class ChildSwitch extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      options: [
        {
          displayName: "Disabled",
          value: "disabled"
        },
        {
          displayName: "Enabled",
          value: "enabled"
        }
      ]
    };
  }

  onSelectOption = selected => {
    this.props.onSelect(this.props.switchName, selected);
  };

  render() {
    const { options } = this.state;
    const { selected } = this.props;
    return (
      <MultiToggle
        options={options}
        selectedOption={selected}
        onSelectOption={this.onSelectOption}
      />
    );
  }
}

家长设置

import MultiToggle from "react-multi-toggle";
import React from "react";
import "react-multi-toggle/style.css";

export default class ParentSwitch extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      options: [
        {
          displayName: "Disabled",
          value: "disabled"
        },
        {
          displayName: "Pending",
          value: "pending"
        },
        {
          displayName: "Enabled",
          value: "enabled"
        }
      ]
    };
  }

  render() {
    const { options } = this.state;
    return (
      <MultiToggle
        options={options}
        selectedOption={this.props.parentSwitch}
        onSelectOption={() => {}}
      />
    );
  }
}

Answer 1

我建议您将您的孩子和父母归为一个组件。假设我们将其命名为Settings。然后，我们创建另一个组件来呈现设置列表和一个按钮。最后一个组件将保存所有设置的值。最后，每次Setting Component Change 的值，我们都会更新列表。查看示例working app here。

应用组件

export default class App extends PureComponent {
  state = {};

  onSettingChange = (settingId, setting) => {
    this.setState(prevState => ({
      ...prevState,
      [settingId]: setting
    }));
  };

  onGetSettingValues = () => {
    console.log(this.state);
  };

  render() {
    return (
      <Fragment>
        <Setting id="setting1" onChange={this.onSettingChange} />
        <Setting id="setting2" onChange={this.onSettingChange} />
        <button onClick={this.onGetSettingValues}>Get All Values</button>
      </Fragment>
    );
  }
}

设置组件

import React, { PureComponent, Fragment } from "react";
import ChildSwitch from "./ChildSwitch";
import ParentSwitch from "./ParentSwitch";

export default class Setting extends PureComponent {
  state = {
    parentVal: "disabled",
    switch1Val: "enabled",
    switch2Val: "disabled"
  };

  componentDidMount() {
    this.setParentSwitchValue();
  }

  setChildSwitchValue = (whichSwitch, selected) => {
    this.setState(
      prevState => ({ ...prevState, [whichSwitch]: selected }),
      this.setParentSwitchValue
    );
  };

  handleChange = () => {
    const { id, onChange } = this.props;
    onChange(id, this.state);
  };

  setParentSwitchValue = () => {
    const { switch1Val, switch2Val } = this.state;
    const switchStates = [switch1Val, switch2Val];
    let parent = "pending";
    if (switchStates.every(val => val === "enabled")) {
      parent = "enabled";
    }
    if (switchStates.every(val => val === "disabled")) {
      parent = "disabled";
    }

    this.setState(
      prevState => ({ ...prevState, parentVal: parent }),
      this.handleChange
    );
  };

  render() {
    const { parentVal, switch1Val, switch2Val } = this.state;
    return (
      <Fragment>
        <div className="boxed">
          Parent Setting 1
          <ParentSwitch
            parentSwitch={parentVal}
            onSelect={this.setParentSwitchValue}
          />
          Setting 1:
          <ChildSwitch
            switchName={"switch1Val"}
            selected={switch1Val}
            onSelect={this.setChildSwitchValue}
          />
          Setting 2:
          <ChildSwitch
            switchName={"switch2Val"}
            selected={switch2Val}
            onSelect={this.setChildSwitchValue}
          />
        </div>
      </Fragment>
    );
  }
}

Answer 2

将所有状态放入一个 context hook。

const SettingsContext = createContext({state1, state2/* all your states in here*/);

然后，您将把整个事情包装到这个上下文中：

<SettingsContext.Provider>
  <App/>
</SettingsContext.Provider>

现在您可以访问任何孩子、父母等的状态。但我建议不要将“禁用”、“启用”等内容存储为字符串，而是将状态存储为 { enabled: true, pending: false}