Question

我有一个div的列表，所有div都有float:left的设置和相等的高度/宽度，所以它们彼此相邻并且如果父级小于项目

非常标准。这是为了创建一个twitter bootstrap图标列表，它给出了这样的结果： enter image description here

我使用下面的代码添加了下一个/上一个键盘导航，但是您会注意到向上/向下箭头键被映射以调用左/右功能。我不知道该怎么办才能真正进行上/下导航？

(function ($) {
    $.widget("ui.iconSelect", {

        // default options
        options: {

        },

        $select: null,

        $wrapper: null,

        $list: null,

        $filter: null,

        $active: null,

        icons: {},

        keys: {
            left: 37,
            up: 38,
            right: 39,
            down: 40

        },

        //initialization function
        _create: function () {

            var that = this;
            that.$select = that.element;

            that.$wrapper = $('<div class="select-icon" tabindex="0"></div>');
            that.$filter = $('<input class="span12" tabindex="-1" placeholder="Filter by class name..."/>').appendTo(that.$wrapper);
            that.$list = $('<div class="select-icon-list"></div>').appendTo(that.$wrapper);


            //build the list of icons
            that.element.find('option').each(function () {
                var $option = $(this);
                var icon = $option.val();

                that.icons[icon] = $('<a data-class="' + icon + '"><i class="icon ' + icon + '"></i></a>');

                if ($option.is(':selected')) {
                    that.icons[icon].addClass('selected active');
                }

                that.$list.append(that.icons[icon]);
            });

            that.$wrapper.insertBefore(that.$select);
            that.$select.addClass('hide');



            that._setupArrowKeysHandler();
            that._setupClickHandler();
            that._setupFilter();
            that.focus('selected');
        },

        focus: function (type) {
            var that = this;
            if (that.$active === null || that.$active.length == 0) {
                if (type == 'first') {
                    that.$active = that.$list.find('a:visible:first');
                } else if (type == 'last') {
                    that.$active = that.$list.find('a:visible:last');
                } else if (type == 'selected') {
                    that.$active = that.$list.find('a.selected:visible:first');
                    that.focus('first');
                }
            }
            that.$active.addClass('active');
            var toScroll = ((that.$list.scrollTop() + that.$active.position().top)-that.$list.height()/2)+that.$active.height()/2;
            //that.$list.scrollTop((that.$list.scrollTop() + top)-that.$list.height()/2);
            that.$list.stop(true).animate({
                scrollTop: toScroll,
                queue: false,
                easing: 'linear'
            }, 200);

            if (type === 'selected') {
                return false;
            }

            that.$select.val(that.$active.data('class'));
            that.$select.trigger('change');

        },

        _setupArrowKeysHandler: function () {
            var that = this;

            that.$wrapper.on('keydown', function (e) {
                switch (e.which) {
                    case that.keys.left:
                        that.moveLeft();
                        break;
                    case that.keys.up:
                        that.moveUp();
                        break;
                    case that.keys.right:
                        that.moveRight();
                        break;
                    case that.keys.down:
                        that.moveDown();
                        break;
                    case 16:
                        return true;
                    case 9:
                        return true;
                    break;
                    default:
                        that.$filter.focus();
                        return true;
                }
                return false;
            });
        },

        _setupFilter: function(){
            var that = this;

            that.$filter.on('keydown keyup keypress paste cut change', function(e){
                that.filter(that.$filter.val());
            });
        },

        _setupClickHandler: function () {
            var that = this;
            that.$list.on('click', 'a', function () {
                that.$wrapper.focus();
                that.$active.removeClass('active');
                that.$active = $(this);
                that.focus('first');
            });
        },

        moveUp: function () {
            var that = this;
            return that.moveLeft();
        },

        moveDown: function () {
            var that = this;
            return that.moveRight();
        },

        moveLeft: function () {
            var that = this;
            that.$active.removeClass('active');
            that.$active = that.$active.prevAll(':visible:first');
            that.focus('last');
            return false;
        },

        moveRight: function () {
            var that = this;
            that.$active.removeClass('active');
            that.$active = that.$active.nextAll(':visible:first');
            that.focus('first');
            return false;
        },

        filter: function(word){
            var that = this;
            var regexp = new RegExp(word.toLowerCase());
            var found = false;
            $.each(that.icons, function(i, $v){
                found = regexp.test(i);
                if(found && !$v.is(':visible')){
                    $v.show();
                } else if(!found && $v.is(':visible')){
                    $v.hide();
                }
            });
        }

    });
})(jQuery);

Answer 1

也许是这样的：http://jsfiddle.net/QFzCY/

var blocksPerRow = 4;

$("body").on("keydown", function(e){
    var thisIndex = $(".selected").index();
    var newIndex = null;
    if(e.keyCode === 38) {
        // up
       newIndex = thisIndex - blocksPerRow;
    }
    else if(e.keyCode === 40) {
        // down
        newIndex = thisIndex + blocksPerRow;       
    }
    if(newIndex !== null) { 
        $(".test").eq(newIndex).addClass("selected").siblings().removeClass("selected");   
    }    
 });

基本上，您可以设置一行中有多少项，然后找到当前索引并减去或添加该数量，以通过新索引选择下一个元素。

如果你需要知道每行有多少个块，你可以这样做：

var offset = null;
var blocksPerRow = 0;
$(".test").each(function(){
    if(offset === null) {
        offset = $(this).offset().top;
    }
    else if($(this).offset().top !== offset) {
        return false;
    }
    blocksPerRow++;
});

要处理“边缘”案件，你可以这样做：

if(newIndex >= $(".test").length) {
    newIndex = $(".test").length - newIndex;
}

Answer 2

    moveUp: function () {
        var that = this;
        var index = $(this).index();
        var containerWidth = parseInt( $('.select-icon-list').innerWidth(), 10);
        var iconWidth = parseInt( $('.select-icon-list > a').width(), 10);
        var noOfCols = Math.floor( containerWidth / iconWidth );
        var newIndex = ( (index - noOfCols) < 0 ) ? index : (index - noOfCols);
        var elem = $('.select-icon-list > a')[index];
    },

缓存任何静态的东西。

使用jQuery上/下/左/右键盘导航？

2 个答案: