ishowshao · March 17, 2017 06:07
diff --git a/list.html b/list.html
 <!DOCTYPE html>
 <html>
 <head>
    <meta charset="utf-8">
    <meta name="viewport"
          content="width=device-width,initial-scale=1.0,minimum-scale=1.0,maximum-scale=1.0,user-scalable=no">
    <title>长列表优化</title>
    <script src="vue.js"></script>
    <style>
        body {
            margin: 0;
        }

        a {
            text-decoration: none;
        }

        #container {
            padding: 0 1em;
            overflow: auto;
            -webkit-overflow-scrolling: touch;
            height: 400px;
        }

        .item {
            height: 40px;
            padding: 10px 0;
            overflow: hidden;
            border-bottom: 1px solid #f1f1f1;
        }

        .item img {
            float: left;
            margin-right: 10px;
            width: 40px;
            height: 40px;
        }

        .item h3 {
            margin: 0;
            font-size: 0.875rem;
            line-height: 1.25rem;
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
            color: #333;
        }

        .item .info {
            font-size: 0.8125rem;
            color: #999;
            line-height: 1.25rem;
            display: flex;
        }

        .item .info > div {
            flex: 1;
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
        }

        #loading {
            background-color: #cccccc;
            -webkit-transition: height 0.3s;
            transition: height 0.3s;
            height: 0;
            overflow: hidden;
        }
    </style>
 </head>
 <body>
 <div id="component">
    <div id="loading" :style="loadingStyle">{{loadingText}}</div>
    <div id="container" @scroll="onScroll" @touchstart="onTouchStart" @touchmove="onTouchMove" @touchend="onTouchEnd">
        <div class="item" v-for="item in list">
            <a href="">
                <img :src="'pics/' + (item + 1) + '.jpg'" width="40">
                <h3>{{item}}</h3>
                <div class="info">
                    <div>热度:9.4亿</div>
                    <div>来源:喜马拉雅</div>
                    <div>主播:未知</div>
                </div>
            </a>
        </div>
    </div>
    <div v-if="scrollBottom === 0">加载中</div>
 </div>
 <script>
    var LOADING_TEXT_INIT = '下拉推荐';
    var LOADING_TEXT_READY = '松开推荐';
    var LOADING_TEXT = '玩命加载中';
    var LOADING_TEXT_RESULT = '成功加载10条';

    var i = 0;
    var list = [];
    for (; i < 20; i++) {
        list.push(i);
    }

    // 模拟ajax取下拉刷新数据
    var fetchData = function (callback) {
        var data = [];
        for (var j = 0; j < 10; j++) {
            data.push(i++);
        }
        setTimeout(function () {
            callback(data);
        }, 800);
    };

    var ITEM_HEIGHT = 61;

    var app = new Vue({
        el: '#component',
        data: {
            startY: 0,
            distance: 0,
            refreshing: false,
            loading: false,
            scrollTop: 0,
            scrollBottom: 1,
            loadingStyle: {
                height: '0px',
                webkitTransition: 'height 0.3s',
                transition: 'height 0.3s'
            },
            loadingText: LOADING_TEXT_INIT,
            threshold: 150, // 触发刷新的下拉距离阈值
            list: list,

            topDetached: [],
            bottomDetached: []
        },
        methods: {
            onScroll: function (e) {
                var me = this;
                var container = e.target;
                this.scrollTop = container.scrollTop;
                this.scrollBottom = container.scrollHeight - container.offsetHeight - container.scrollTop;
 //                console.log(this.scrollTop, this.scrollBottom);

                // 这里以10行列表为单位进行移除
                // 坑：批量移除会一次调整较大高度的scroll位置移动，由于DOM滞后于滚屏，可能导致可滚动区域不足，会导致错位
                // 这个坑确实不好描述，但是多留一些留存的DOM就可避免

                // 上滑
                if (this.scrollTop > 30 * ITEM_HEIGHT) {
                    this.topDetached.push.apply(this.topDetached, this.list.splice(0, 10));
                    e.target.scrollTop = this.scrollTop - 10 * ITEM_HEIGHT;
                }
                if (this.scrollBottom < 10 * ITEM_HEIGHT && this.bottomDetached.length > 0) {
                    this.list.push(...this.bottomDetached.splice(this.bottomDetached.length - 10, 10));
                }

                // 向下滚屏
                if (this.scrollBottom > 30 * ITEM_HEIGHT) {
                    this.bottomDetached.push.apply(this.bottomDetached, this.list.splice(this.list.length - 10, 10));
                }
                if (this.scrollTop < 10 * ITEM_HEIGHT && this.topDetached.length > 0) {
                    this.list.unshift.apply(this.list, this.topDetached.splice(this.topDetached.length - 10, 10));
                    e.target.scrollTop += 10 * ITEM_HEIGHT;
                }

                // 到底部自动加载下一页
                if (this.scrollBottom === 0) {
                    fetchData(function (data) {
                        me.list.push.apply(me.list, data);
                        me.scrollBottom = false;
                    });
                }
            },
            onTouchStart: function (e) {
                if (this.loading) {
                    e.preventDefault();
                    return;
                }

                this.startY = e.changedTouches[0].clientY;
                if (this.scrollTop === 0) {
                    this.loadingStyle.webkitTransition = 'none';
                    this.loadingStyle.transition = 'none';
                    this.loadingText = LOADING_TEXT_INIT;
                }
            },
            onTouchMove: function (e) {
                if (this.loading) {
                    e.preventDefault();
                    return;
                }

                this.distance = e.changedTouches[0].clientY - this.startY;

                // 只有在最顶部才有可能开启下拉刷新
                if (this.scrollTop === 0) {
                    // 只有下拉才触发刷新，上划不能做任何事
                    this.refreshing = this.distance > 0;

                    if (this.refreshing) {
                        e.preventDefault();
                        this.loadingStyle.height = this.distance * (0.4 - 0.4 * this.distance / 2000) + 'px';
                        if (this.distance > this.threshold) {
                            this.loadingText = LOADING_TEXT_READY;
                        }
                    }
                }
            },
            onTouchEnd: function (e) {
                var me = this;

                if (this.refreshing) {
                    this.loadingStyle.webkitTransition = 'height 0.3s';
                    this.loadingStyle.transition = 'height 0.3s';

                    if (this.distance > this.threshold) {
                        e.preventDefault();
                        this.loadingStyle.height = '30px';
                        this.loadingText = LOADING_TEXT;
                        this.loading = true;

                        fetchData(function (data) {
                            me.loadingText = LOADING_TEXT_RESULT;
                            me.list.unshift.apply(me.list, data); // me.list.unshift(...data);
                            me.loadingStyle.height = '0px';
                            me.loading = false;
                        });
                    }
                    else {
                        this.loadingStyle.height = '0px';
                    }

                    this.refreshing = false;
                }

                this.distance = 0;
            }
        }
    });

 </script>
 </body>
 </html>
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	<meta name="viewport"
	content="width=device-width,initial-scale=1.0,minimum-scale=1.0,maximum-scale=1.0,user-scalable=no">
	<title>长列表优化</title>
	<script src="vue.js"></script>
	<style>
	body {
	margin: 0;
	}

	a {
	text-decoration: none;
	}

	#container {
	padding: 0 1em;
	overflow: auto;
	-webkit-overflow-scrolling: touch;
	height: 400px;
	}

	.item {
	height: 40px;
	padding: 10px 0;
	overflow: hidden;
	border-bottom: 1px solid #f1f1f1;
	}

	.item img {
	float: left;
	margin-right: 10px;
	width: 40px;
	height: 40px;
	}

	.item h3 {
	margin: 0;
	font-size: 0.875rem;
	line-height: 1.25rem;
	white-space: nowrap;
	overflow: hidden;
	text-overflow: ellipsis;
	color: #333;
	}

	.item .info {
	font-size: 0.8125rem;
	color: #999;
	line-height: 1.25rem;
	display: flex;
	}

	.item .info > div {
	flex: 1;
	white-space: nowrap;
	overflow: hidden;
	text-overflow: ellipsis;
	}

	#loading {
	background-color: #cccccc;
	-webkit-transition: height 0.3s;
	transition: height 0.3s;
	height: 0;
	overflow: hidden;
	}
	</style>
	</head>
	<body>
	<div id="component">
	<div id="loading" :style="loadingStyle">{{loadingText}}</div>
	<div id="container" @scroll="onScroll" @touchstart="onTouchStart" @touchmove="onTouchMove" @touchend="onTouchEnd">
	<div class="item" v-for="item in list">
	<a href="">
	<img :src="'pics/' + (item + 1) + '.jpg'" width="40">
	<h3>{{item}}</h3>
	<div class="info">
	<div>热度:9.4亿</div>
	<div>来源:喜马拉雅</div>
	<div>主播:未知</div>
	</div>
	</a>
	</div>
	</div>
	<div v-if="scrollBottom === 0">加载中</div>
	</div>
	<script>
	var LOADING_TEXT_INIT = '下拉推荐';
	var LOADING_TEXT_READY = '松开推荐';
	var LOADING_TEXT = '玩命加载中';
	var LOADING_TEXT_RESULT = '成功加载10条';

	var i = 0;
	var list = [];
	for (; i < 20; i++) {
	list.push(i);
	}

	// 模拟ajax取下拉刷新数据
	var fetchData = function (callback) {
	var data = [];
	for (var j = 0; j < 10; j++) {
	data.push(i++);
	}
	setTimeout(function () {
	callback(data);
	}, 800);
	};

	var ITEM_HEIGHT = 61;

	var app = new Vue({
	el: '#component',
	data: {
	startY: 0,
	distance: 0,
	refreshing: false,
	loading: false,
	scrollTop: 0,
	scrollBottom: 1,
	loadingStyle: {
	height: '0px',
	webkitTransition: 'height 0.3s',
	transition: 'height 0.3s'
	},
	loadingText: LOADING_TEXT_INIT,
	threshold: 150, // 触发刷新的下拉距离阈值
	list: list,

	topDetached: [],
	bottomDetached: []
	},
	methods: {
	onScroll: function (e) {
	var me = this;
	var container = e.target;
	this.scrollTop = container.scrollTop;
	this.scrollBottom = container.scrollHeight - container.offsetHeight - container.scrollTop;
	// console.log(this.scrollTop, this.scrollBottom);

	// 这里以10行列表为单位进行移除
	// 坑：批量移除会一次调整较大高度的scroll位置移动，由于DOM滞后于滚屏，可能导致可滚动区域不足，会导致错位
	// 这个坑确实不好描述，但是多留一些留存的DOM就可避免

	// 上滑
	if (this.scrollTop > 30 * ITEM_HEIGHT) {
	this.topDetached.push.apply(this.topDetached, this.list.splice(0, 10));
	e.target.scrollTop = this.scrollTop - 10 * ITEM_HEIGHT;
	}
	if (this.scrollBottom < 10 * ITEM_HEIGHT && this.bottomDetached.length > 0) {
	this.list.push(...this.bottomDetached.splice(this.bottomDetached.length - 10, 10));
	}

	// 向下滚屏
	if (this.scrollBottom > 30 * ITEM_HEIGHT) {
	this.bottomDetached.push.apply(this.bottomDetached, this.list.splice(this.list.length - 10, 10));
	}
	if (this.scrollTop < 10 * ITEM_HEIGHT && this.topDetached.length > 0) {
	this.list.unshift.apply(this.list, this.topDetached.splice(this.topDetached.length - 10, 10));
	e.target.scrollTop += 10 * ITEM_HEIGHT;
	}

	// 到底部自动加载下一页
	if (this.scrollBottom === 0) {
	fetchData(function (data) {
	me.list.push.apply(me.list, data);
	me.scrollBottom = false;
	});
	}
	},
	onTouchStart: function (e) {
	if (this.loading) {
	e.preventDefault();
	return;
	}

	this.startY = e.changedTouches[0].clientY;
	if (this.scrollTop === 0) {
	this.loadingStyle.webkitTransition = 'none';
	this.loadingStyle.transition = 'none';
	this.loadingText = LOADING_TEXT_INIT;
	}
	},
	onTouchMove: function (e) {
	if (this.loading) {
	e.preventDefault();
	return;
	}

	this.distance = e.changedTouches[0].clientY - this.startY;

	// 只有在最顶部才有可能开启下拉刷新
	if (this.scrollTop === 0) {
	// 只有下拉才触发刷新，上划不能做任何事
	this.refreshing = this.distance > 0;

	if (this.refreshing) {
	e.preventDefault();
	this.loadingStyle.height = this.distance * (0.4 - 0.4 * this.distance / 2000) + 'px';
	if (this.distance > this.threshold) {
	this.loadingText = LOADING_TEXT_READY;
	}
	}
	}
	},
	onTouchEnd: function (e) {
	var me = this;

	if (this.refreshing) {
	this.loadingStyle.webkitTransition = 'height 0.3s';
	this.loadingStyle.transition = 'height 0.3s';

	if (this.distance > this.threshold) {
	e.preventDefault();
	this.loadingStyle.height = '30px';
	this.loadingText = LOADING_TEXT;
	this.loading = true;

	fetchData(function (data) {
	me.loadingText = LOADING_TEXT_RESULT;
	me.list.unshift.apply(me.list, data); // me.list.unshift(...data);
	me.loadingStyle.height = '0px';
	me.loading = false;
	});
	}
	else {
	this.loadingStyle.height = '0px';
	}

	this.refreshing = false;
	}

	this.distance = 0;
	}
	}
	});

	</script>
	</body>
	</html>