Question

我似乎无法找到如何实现这一目标的答案，但这是我多次见过的一个功能。基本上我正在回显列表，我想创建使用箭头键/输入突出显示和选择这些项目的功能。有人可以帮助我了解如何实现这一目标吗？我知道如何使用密钥代码（当然），而不是如何将其转换为用于选择列表中项目的功能代码...

我在想也许我必须要有一些隐藏的单选按钮才能将其标记为选中或不...但即使这样我也不知道如何从一个单选按钮跳到另一个单选按钮在列表中。所以如果有人能帮我一把，我真的很感激。谢谢。

Answer 1

由于您没有真正解释您遇到的问题，我刚刚创建了一个通用的解决方案。希望这会有所帮助：

var li = $('li');
var liSelected;
$(window).keydown(function(e) {
    if(e.which === 40) {
        if(liSelected) {
            liSelected.removeClass('selected');
            next = liSelected.next();
            if(next.length > 0) {
                liSelected = next.addClass('selected');
            } else {
                liSelected = li.eq(0).addClass('selected');
            }
        } else {
            liSelected = li.eq(0).addClass('selected');
        }
    } else if(e.which === 38) {
        if(liSelected) {
            liSelected.removeClass('selected');
            next = liSelected.prev();
            if(next.length > 0) {
                liSelected = next.addClass('selected');
            } else {
                liSelected = li.last().addClass('selected');
            }
        } else {
            liSelected = li.last().addClass('selected');
        }
    }
});

JSFiddle：http://jsfiddle.net/Vtn5Y/

Answer 2

2020更新

万一有人想在 Vue.js 中做到这一点，我在下面的代码中添加了必要的注释，其余内容不言自明

HTML

<script type="text/x-template" id="list">
  <div id="list-container" ref="root">
    <div v-for="item in items" :key="item.id" class="list-item" :class="item.id === selectedId ? 'selected': ''" @click="select(item.id)">
      {{item.value}}
    </div>
  </div>
</script>

<div id="app">
  <list></list>
</div>

CSS

* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}

html {
  height: 100%;
}

body {
  height: 100%;
  min-height: 100%;
  padding: 1rem;
  font-family: 'Tahoma', sans-serif;
}

.list-item {
  padding: 1rem 0.25rem;
}

.selected {
  background: lightyellow;
}

JS

const items = new Array(100).fill(null).map((item, index) => {
  return { id: index, value: "Item " + index };
});

// https://stackoverflow.com/questions/5685589/scroll-to-element-only-if-not-in-view-jquery
function scrollIntoViewIfNeeded(target) {
    var rect = target.getBoundingClientRect();
    if (rect.bottom > window.innerHeight) {
        target.scrollIntoView(false);
    }
    if (rect.top < 0) {
        target.scrollIntoView();
    } 
}

Vue.component("list", {
  template: "#list",
  data() {
    return {
      items,
      selectedId: 0
    };
  },
  methods: {
    select(itemId) {
      this.selectedId = itemId;
      scrollIntoViewIfNeeded(this.$refs.root.children[itemId])
      // this.$refs.root.children[item.id].scrollIntoView({ behavior: "smooth" });
    },
    handleKeyDown(event) {
      switch (event.keyCode) {
        // In case of left arrow key move to the last item
        case 37:
          if (this.selectedId > 0) {
            this.select(this.selectedId - 1);
          }
          // Prevent the default scroll event from firing
          event.preventDefault();
          break;
        // In case of up arrow key, move to the last item
        case 38:
          if (this.selectedId > 0) {
            this.select(this.selectedId - 1);
          }
          event.preventDefault();
          break;
        // In case of right arrow key, move to the next item
        case 39:
          if (this.selectedId < this.items.length - 1) {
            this.select(this.selectedId + 1);
          }
          event.preventDefault();
          break;
        // In case of down arrow key, move to the next item
        case 40:
          if (this.selectedId < this.items.length - 1) {
            this.select(this.selectedId + 1);
          }
          event.preventDefault();
          break;
      }
    }
  },
  mounted() {
    window.addEventListener("keydown", this.handleKeyDown);
  },
  destroyed() {
    window.removeEventListener("keydown", this.handleKeyDown);
  }
});

new Vue({
  el: "#app"
});

Answer 3

本机JavaScript的示例

var ul = document.getElementById('list');
var liSelected;
var index = -1;

document.addEventListener('keydown', function(event) {
var len = ul.getElementsByTagName('li').length-1;
  if(event.which === 40) {
index++;
  //down 
  if (liSelected) {
			removeClass(liSelected, 'selected');
      next = ul.getElementsByTagName('li')[index];
      if(typeof next !== undefined && index <= len) {
      
                liSelected = next;
            } else {
             	index = 0;
                 liSelected = ul.getElementsByTagName('li')[0];
            }
            addClass(liSelected, 'selected');
            console.log(index);
    }
    else {
    index = 0;
    
   	 liSelected = ul.getElementsByTagName('li')[0];
			 addClass(liSelected, 'selected');
    }
  }
  else if (event.which === 38) {
  
  //up
    if (liSelected) {
			removeClass(liSelected, 'selected');
      index--;
      console.log(index);
      next = ul.getElementsByTagName('li')[index];
      if(typeof next !== undefined && index >= 0) {
                liSelected = next;
            } else {
            		index = len;
                 liSelected = ul.getElementsByTagName('li')[len];
            }
            addClass(liSelected, 'selected');
    }
    else {
    index = 0;
   	 liSelected = ul.getElementsByTagName('li')[len];
			addClass(liSelected, 'selected');
    }
  }
}, false);

function removeClass(el, className) {
    if(el.classList) {
        el.classList.remove(className);
    } else {
        el.className = el.className.replace(new RegExp('(^|\\b)' + className.split(' ').join('|') + '(\\b|$)', 'gi'), ' ');
    }
};

function addClass(el, className) {
    if(el.classList) {
        el.classList.add(className);
    } else {
        el.className += ' ' + className;
    }
};

li.selected {background:yellow}

<ul id="list">
    <li>Item 1</li>
    <li>Item 2</li>
    <li>Item 3</li>
    <li>Item 4</li>
</ul>

https://jsfiddle.net/m6watqpe/

Answer 4

这可能取决于浏览器。它似乎仅在无线电输入彼此相邻时才起作用（标签也可以）。

<input type="radio" ... /> 
<input type="radio" ... />
<input type="radio" ... />

但这会破坏Firefox和其他浏览器中的无线电导航：

<div><input type="radio" ... /> ... </div>
<div><input type="radio" ... /> ... </div>

一旦你想要制作比简单列表（类别......）更复杂的东西，这很烦人。

使用箭头键浏览列表？（JavaScript的/ JQ）

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使用箭头键浏览列表？ （JavaScript的/ JQ）

4 个答案:

使用箭头键浏览列表？（JavaScript的/ JQ）