你如何动画FB.Canvas.scrollTo？

Question

我创建了一个设置大小(大约2,000像素高)的应用程序,并有一个调用FB.Canvas.scrollTo的菜单,以帮助用户导航长页面.

有没有办法添加平滑的滚动效果？Facebook没有在其开发者博客上提供任何解决方案.

Answer 1

使用@ Jonny的方法,您可以更简单地使用

function scrollTo(y){
    FB.Canvas.getPageInfo(function(pageInfo){
            $({y: pageInfo.scrollTop}).animate(
                {y: y},
                {duration: 1000, step: function(offset){
                    FB.Canvas.scrollTo(0, offset);
                }
            });
    });
}

Answer 2

今天遇到了同样的问题 - 我想出了一些javascript,它利用jQuery的animate方法提供了一些缓动 - 滚动仍然是一个触摸生涩(我猜这是因为FB.Canvas.scrollTo代理).无论如何,这里是片段:

function scrollToTop() {
    // We must call getPageInfo() async otherwise we will get stale data.
    FB.Canvas.getPageInfo(function (pageInfo) { 

        // The scroll position of your app's iFrame.
        var iFrameScrollY = pageInfo.scrollTop;

        // The y position of the div you want to scroll up to.
        var targetDivY = $('#targetDiv').position().top;

        // Only scroll if the user has scrolled the window beneath the target y position.
        if (iFrameScrollY > targetDivY) {
            var animOptions = {

                // This function will be invoked each 'tick' of the animation.
                step: function () {
                    // As we don't have control over the Facebook iFrame we have to ask the Facebook JS API to 
                    // perform the scroll for us.
                    FB.Canvas.scrollTo(0, this.y);
                },

                // How long you want the animation to last in ms.
                duration: 200
            };

            // Here we are going to animate the 'y' property of the object from the 'iFrameScrollY' (the current 
            // scroll position) to the y position of your target div.
            $({ y: iFrameScrollY }).animate({ y: targetDivY }, animOptions);
        }
    });
}