dreamland/lib/graceUI/jsTools/graceLazyload.js

/**
懒加载
来自 grace.hcoder.net 
作者 hcoder 深海 5213606@qq.com

版权声明 : 
GraceUI 的版权约束是不能转售或者将 GraceUI 直接发布到公开渠道！
侵权必究，请遵守版权约定！
*/
var graceLazyWinHeight = 500;
var graceLazyTimer = null;
module.exports = {
	load : function(top, _page){
		if (graceLazyTimer != null){clearTimeout(graceLazyTimer);}
		graceLazyTimer = setTimeout(function(){
			uni.getSystemInfo({
				success: function (res) {
					graceLazyWinHeight = res.windowHeight;
					//遍历img
					uni.createSelectorQuery().selectAll('.grace-img-lazy').fields(
						{
							rect: true,
						}, function (res) {
							var isShow = [];
							//检查图片是否在窗口可视区域
							for (var i = 0; i < res.length; i++) {
								if (res[i].top <= graceLazyWinHeight + top) {
									isShow[i] = true;
								} else {
									break;
								}
							}
							_page.isShow = isShow;
						}
					).exec();
				}
			});
		}, 200);
	}
}