JavaScript范围问题导致只有一个绑定工作

Question

我正在使用Raphael.js库进行特定的工作.我正在创建圈子和绑定悬停事件,显示/隐藏文本.问题是只显示/隐藏了最后一个圆圈上的文字,即使我在其他圆圈上空盘旋.

这是我的代码:

for(var i=0; i<feedData.length; i++){               
                var x = ((i+1)*diff);
                var t = r.text(x, 120, feedData[i].title).hide();

                var c = r.circle(x,150,10);
                c.attr({fill: "red"});
                c.attr({stroke: "red"});
                c.attr({title: feedData[i].title});             
                c.hover(function (event) {
                    this.animate({r: 13}, 200);
                    t.show();
                }, function (event) {
                    this.animate({r: 10}, 200);
                    t.hide();
                });             
            }

对于Raphael.js参考

http://raphaeljs.com/reference.html#events

Answer 1

好吧,我对raphael库一无所知,但看起来你可以将你c.hover的自我调用函数包装起来,以创建一个引用正确值的闭包t.

(function( local_t ) {
    c.hover(function (event) {
        this.animate({r: 13}, 200);
        local_t.show();
    }, function (event) {
        this.animate({r: 10}, 200);
        local_t.hide();
    });
})( t );

这样,当你创建hover事件处理程序时,它将传入值的值t,并将其作为局部变量t_local(或者你给它的任何名称)引用它,这将持续到调用处理程序(和之后).

所以完整的代码将是:

for(var i=0; i<feedData.length; i++){               
    var x = ((i+1)*diff);
    var t = r.text(x, 120, feedData[i].title).hide();

    var c = r.circle(x,150,10);
    c.attr({fill: "red"});
    c.attr({stroke: "red"});
    c.attr({title: feedData[i].title});             
    (function( local_t ) {
        c.hover(function (event) {
            this.animate({r: 13}, 200);
            local_t.show();
        }, function (event) {
            this.animate({r: 10}, 200);
            local_t.hide();
        });
    })( t );         
}

编辑:您可以将整个for()语句包含在内部,但我认为这不会对Chrome您在下面的评论中提到的具体问题产生影响.

for(var i = 0; i < feedData.length; i++){
     (function( local_i ) {
        var x = ( ( local_i + 1) * diff );
        var t = r.text(x, 120, feedData[ local_i ].title).hide();

        var c = r.circle(x, 150, 10);
        c.attr({fill: "red"});
        c.attr({stroke: "red"});
        c.attr({title: feedData[ local_i ].title});             

        c.hover(function (event) {
            this.animate({r: 13}, 200);
            local_t.show();
        }, function (event) {
            this.animate({r: 10}, 200);
            local_t.hide();
        });
    })( i );         
}