React Material UI ListItem 點擊

Question

我想創建一個國家列表，其中的 ListItems 是可點擊的，並且每個 ListItem 在點擊時都有一個靠近文本的圖標。 我創建了一個列表並實現了列表的可點擊屬性。 但是，當我單擊列表中的一個列表項時，我無法在 1 單擊中選擇另一項，它首先取消選擇前一個，然后選擇另一個。 這是我的實現包含的代碼部分：

class CountryList extends Component {
  constructor(props) {
    super(props);
    this.state = {clicked: false};
    this.handleClick = this.handleClick.bind(this);
  }

  handleClick() {
    this.setState(state => ({
      clicked: !state.clicked
    }));
  }

  render() {
    const {classes} = this.props;
    const { clicked } = this.state;

    let listItems = myList.map((item) =>
      <>
        <ListItem className={ clicked ? classes.listItemClicked : classes.listItemNotClicked }
          onClick={this.handleClick} classes={classes.ListItem} button key={item.id}>
        
            {clicked ? 
            <ListItemIcon><DoneIcon style={{ color: 'rgb(239, 239, 239)', fontSize: '2.2rem' }}/></ListItemIcon>
           : <ListItemIcon><DoneIcon style={{ display: 'none', color: 'rgb(239, 239, 239)', fontSize: '2.2rem', backgroundColor: 'rgb(239, 239, 239)' }}/></ListItemIcon>}

           <ListItemText classes={{primary: classes.listItemText}} primary={item.value} />
       </ListItem>
       <Divider /> 
      </>
    );

    return (
      <List className={classes.list}>{listItems}</List>
    );
  }
}


const myList = [
  {id: 1, value: 'Albania'}, {id: 2, value: 'Austria'}, {id: 3, value: 'Belarus'}, {id: 4, value: 'Belgium'}, 
  {id: 5, value: 'Bosnia'}, {id: 6, value: 'Bulgaria'}, {id: 7, value: 'Croatia'}, {id: 8, value: 'Cyprus'}, 
  {id: 9, value: 'Czech'}, {id: 10, value: 'Denmark'}, {id: 11, value: 'Estonia'}, {id: 12, value: 'Finland'}, 
  {id: 13, value: 'France'}, {id: 14, value: 'Germany'}, {id: 15, value: 'Greece'}, {id: 16, value: 'Hungary'}, 
  {id: 17, value: 'Iceland'}, {id: 18, value: 'Ireland'}, {id: 19, value: 'Italy'}, {id: 20, value: 'Latvia'}, 
  {id: 21, value: 'Lithuania'}, {id: 22, value: 'Luxembourg'}, {id: 23, value: 'Macedonia'}, 
  {id: 24, value: 'Malta'}, {id: 25, value: 'Moldova'}, {id: 26, value: 'Montenegro'}, 
  {id: 27, value: 'Netherlands'}, {id: 28, value: 'Norway'}, {id: 29, value: 'Pakistan'}, 
  {id: 30, value: 'Poland'}, {id: 31, value: 'Portugal'}, {id: 32, value: 'Romania'}, {id: 33, value: 'Russia'}, 
  {id: 34, value: 'Serbia'}, {id: 35, value: 'Slovakia'}, {id: 36, value: 'Slovenia'}, 
  {id: 37, value: 'Spain'}, {id: 38, value: 'Sweden'}, {id: 39, value: 'Switzerland'}, {id: 40, value: 'Turkey'}, 
  {id: 41, value: 'Ukraine'}, {id: 42, value: 'Others'}
];

這是 App.js 文件中的代碼：

<CountryList myList={myList} />

另外，我在文本之前添加了一個圖標。 當我單擊 1 個項目時，它會顯示該圖標，但如果我的鼠標在其上，它還會顯示另一個元素圖標。 我想顯示被點擊元素的圖標。 我怎樣才能做到這一點？

這是屏幕截圖：

仔細看，比利時旁邊有一個圖標。

這是codesandbox中代碼的鏈接：https ://codesandbox.io/s/gifted-snow-5p1gd? file=/ src/Country.js

Answer 1

這是一個工作演示

您需要將活動列表項保持在某種狀態，正如我在您的代碼中看到的this.state.clicked這是一個布爾值，因此現在您無法設置單擊元素的樣式，因為沒有引用選擇哪個

設置狀態以保留單擊的項目

this.state = { clickedItem: "" };

更改onClick to。

<ListItem
    key={item.id}
    className={
      this.state.clickedItem === item.id
        ? classes.listItemClicked
        : classes.listItemNotClicked
    }
    onClick={() => this.handleClick(item)}
>

在 onCLick 中將點擊的項目設置為狀態

handleClick(item) {
  this.setState({
    clickedItem: item.id
  });
}

現在您在狀態中擁有單擊的項目，在下一次渲染中（由於上述狀態更改而發生），您可以在渲染中具有以下邏輯

<ListItem
  key={item.id}
  className={
    this.state.clickedItem === item.id //if item.id === clickedItemId then add a separate css class
      ? classes.listItemClicked
      : classes.listItemNotClicked
  }
  onClick={() => this.handleClick(item)}
>
  <ListItemIcon>
    //if item.id === clickedItemId then show the DoneIcon
    {this.state.clickedItem === item.id && (
      <DoneIcon
        style={{ color: "rgb(239, 239, 239)", fontSize: "2.2rem" }}
      />
    )}
  </ListItemIcon>
  <ListItemText primary={item.value} />
</ListItem>

Answer 2

您必須使用索引映射單擊。 嘗試這個：

 class CountryList extends Component { constructor(props) { super(props); this.state = {clicked: null}; this.handleClick = this.handleClick.bind(this); } handleClick(key) { this.setState(state => ({ clicked: key })); } render() { const {classes} = this.props; const { clicked } = this.state; let listItems = myList.map((item, index) => <> <ListItem className={ clicked == index ? classes.listItemClicked : classes.listItemNotClicked } onClick={this.handleClick} classes={classes.ListItem} button key={item.id}> {clicked == index ? <ListItemIcon><DoneIcon style={{ color: 'rgb(239, 239, 239)', fontSize: '2.2rem' }}/></ListItemIcon> : <ListItemIcon><DoneIcon style={{ display: 'none', color: 'rgb(239, 239, 239)', fontSize: '2.2rem', backgroundColor: 'rgb(239, 239, 239)' }}/></ListItemIcon>} <ListItemText classes={{primary: classes.listItemText}} primary={item.value} /> </ListItem> <Divider /> </> ); return ( <List className={classes.list}>{listItems}</List> ); } } const myList = [ {id: 1, value: 'Albania'}, {id: 2, value: 'Austria'}, {id: 3, value: 'Belarus'}, {id: 4, value: 'Belgium'}, {id: 5, value: 'Bosnia'}, {id: 6, value: 'Bulgaria'}, {id: 7, value: 'Croatia'}, {id: 8, value: 'Cyprus'}, {id: 9, value: 'Czech'}, {id: 10, value: 'Denmark'}, {id: 11, value: 'Estonia'}, {id: 12, value: 'Finland'}, {id: 13, value: 'France'}, {id: 14, value: 'Germany'}, {id: 15, value: 'Greece'}, {id: 16, value: 'Hungary'}, {id: 17, value: 'Iceland'}, {id: 18, value: 'Ireland'}, {id: 19, value: 'Italy'}, {id: 20, value: 'Latvia'}, {id: 21, value: 'Lithuania'}, {id: 22, value: 'Luxembourg'}, {id: 23, value: 'Macedonia'}, {id: 24, value: 'Malta'}, {id: 25, value: 'Moldova'}, {id: 26, value: 'Montenegro'}, {id: 27, value: 'Netherlands'}, {id: 28, value: 'Norway'}, {id: 29, value: 'Pakistan'}, {id: 30, value: 'Poland'}, {id: 31, value: 'Portugal'}, {id: 32, value: 'Romania'}, {id: 33, value: 'Russia'}, {id: 34, value: 'Serbia'}, {id: 35, value: 'Slovakia'}, {id: 36, value: 'Slovenia'}, {id: 37, value: 'Spain'}, {id: 38, value: 'Sweden'}, {id: 39, value: 'Switzerland'}, {id: 40, value: 'Turkey'}, {id: 41, value: 'Ukraine'}, {id: 42, value: 'Others'} ];