【报Bug】在 iOS 上 nvue list 组件使用 setSpecialEffects 设置 tabs 吸顶，tabs 切换时 list 会闪动

示例代码：

<template>  
    <list :id="pageId" class="page" :bounce="false" fixFreezing="true">  
        <cell>  
            <view id="head" class="header">  
                <text class="header-title">header</text>  
            </view>  
        </cell>  
        <cell>  
            <view class="tabs" :style="'height:' + pageHeight + 'px'">  
                <scroll-view ref="tabbar1" id="tab-bar" class="tab-bar" :scroll="false" :scroll-x="true"  
                    :show-scrollbar="false" :scroll-into-view="scrollInto">  
                    <view style="flex-direction: column;">  
                        <view style="flex-direction: row;">  
                            <view class="uni-tab-item" v-for="(tab,index) in tabList" :key="tab.id" :id="tab.id" :ref="'tabitem'+index"  
                                :data-id="index" :data-current="index" @click="ontabtap">  
                                <text class="uni-tab-item-title" :class="tabIndex==index ? 'uni-tab-item-title-active' : ''">{{tab.name}}</text>  
                            </view>  
                        </view>  
                        <view class="scroll-view-indicator">  
                            <view ref="underline" class="scroll-view-underline" :class="isTap ? 'scroll-view-animation':''"  
                                :style="{left: indicatorLineLeft + 'px', width: indicatorLineWidth + 'px'}"></view>  
                        </view>  
                    </view>  
                </scroll-view>  
                <view class="tab-bar-line"></view>  
                <swiper class="tab-view" ref="swiper1" id="tab-bar-view" :current="tabIndex" :duration="300" @change="onswiperchange"  
                    @transition="onswiperscroll" @animationfinish="animationfinish" @onAnimationEnd="animationfinish">  
                    <swiper-item class="swiper-item" v-for="(page, index) in tabList" :key="index">  
                        <swiper-page class="swiper-page" :pid="page.pageid" :parentId="pageId" ref="page"></swiper-page>  
                    </swiper-item>  
                </swiper>  
            </view>  
        </cell>  
    </list>  
</template>  

<script>  
    // #ifdef APP-PLUS  
    const dom = weex.requireModule('dom');  
    // #endif  

    // 缓存每页最多  
    const MAX_CACHE_DATA = 100;  

    // 缓存页签数量  
    const MAX_CACHE_PAGE = 3;  
    const TAB_PRELOAD_OFFSET = 1;  

    import swiperPage from './swiper-page.nvue';  

    export default {  
        components: {  
            swiperPage  
        },  
        data() {  
            return {  
                tabList: [],  
                tabIndex: 0,  
                cacheTab: [],  
                scrollInto: "",  
                indicatorLineLeft: 0,  
                indicatorLineWidth: 0,  
                isTap: false,  
                showTitleView: true,  
                pageHeight: 300,  
                pageId: "page"  
            }  
        },  
        onLoad() {  
            for (var i = 0; i < 6; i++) {  
                this.tabList.push({  
                    id: "tab" + i,  
                    name: 'Tab ' + (i + 1),  
                    pageid: i + 1  
                })  
            }  
        },  
        onReady() {  
            this.pageHeight = uni.getSystemInfoSync().windowHeight;  
            this._lastTabIndex = 0;  
            this.swiperWidth = 0;  
            this.tabbarWidth = 0;  
            this.tabListSize = {};  
            this._touchTabIndex = 0;  
            this._headHeight = 100;  

            this.pageList = this.$refs.page;  
            this.selectorQuery();  
        },  
        methods: {  
            ontabtap(e) {  
                let index = e.target.dataset.current || e.currentTarget.dataset.current;  
                //let offsetIndex = this._touchTabIndex = Math.abs(index - this._lastTabIndex) > 1;  

                // #ifdef APP-PLUS || H5 || MP-WEIXIN || MP-QQ  
                this.isTap = true;  
                var currentSize = this.tabListSize[index];  
                this.updateIndicator(currentSize.left, currentSize.width);  
                this._touchTabIndex = index;  
                // #endif  

                this.switchTab(index);  
            },  
            onswiperchange(e) {  
                // 注意：百度小程序会触发2次  

                // #ifndef APP-PLUS || H5 || MP-WEIXIN || MP-QQ  
                let index = e.target.current || e.detail.current;  
                this.switchTab(index);  
                // #endif  
            },  
            onswiperscroll(e) {  
                if (this.isTap) {  
                    return;  
                }  

                var offsetX = e.detail.dx;  
                var preloadIndex = this._lastTabIndex;  
                if (offsetX > TAB_PRELOAD_OFFSET) {  
                    preloadIndex++;  
                } else if (offsetX < -TAB_PRELOAD_OFFSET) {  
                    preloadIndex--;  
                }  
                if (preloadIndex === this._lastTabIndex || preloadIndex < 0 || preloadIndex > this.pageList.length - 1) {  
                    return;  
                }  
                if (this.pageList[preloadIndex].dataList.length === 0) {  
                    this.loadTabData(preloadIndex);  
                }  

                // #ifdef APP-PLUS || H5 || MP-WEIXIN || MP-QQ  
                var percentage = Math.abs(this.swiperWidth / offsetX);  
                var currentSize = this.tabListSize[this._lastTabIndex];  
                var preloadSize = this.tabListSize[preloadIndex];  
                var lineL = currentSize.left + (preloadSize.left - currentSize.left) / percentage;  
                var lineW = currentSize.width + (preloadSize.width - currentSize.width) / percentage;  
                this.updateIndicator(lineL, lineW);  
                // #endif  
            },  
            animationfinish(e) {  
                // #ifdef APP-PLUS || H5 || MP-WEIXIN || MP-QQ  
                let index = e.detail.current;  
                if (this._touchTabIndex === index) {  
                    this.isTap = false;  
                }  
                this._lastTabIndex = index;  
                this.switchTab(index);  
                this.updateIndicator(this.tabListSize[index].left, this.tabListSize[index].width);  
                // #endif  
            },  
            selectorQuery() {  
                // #ifdef APP-NVUE  
                uni.createSelectorQuery().in(this).select('#head').boundingClientRect().exec(rect => {  
                    this._headHeight = rect[0].height;  
                });  

                // 查询 tabbar 宽度  
                uni.createSelectorQuery().in(this).select('#tab-bar').boundingClientRect().exec(rect => {  
                    this.tabbarWidth = rect[0].width;  
                });  
                // 查询 tabview 宽度  
                uni.createSelectorQuery().in(this).select('#tab-bar-view').boundingClientRect().exec(rect => {  
                    this.swiperWidth = rect[0].width;  
                });  

                // 因 nvue 暂不支持 class 查询  
                var queryTabSize = uni.createSelectorQuery().in(this);  
                for (var i = 0; i < this.tabList.length; i++) {  
                    queryTabSize.select('#' + this.tabList[i].id).boundingClientRect();  
                }  
                queryTabSize.exec(rects => {  
                    rects.forEach((rect) => {  
                      console.log(rect);  
                        this.tabListSize[rect.dataset.id] = rect;  
                    })  
                    this.updateIndicator(this.tabListSize[this.tabIndex].left, this.tabListSize[this.tabIndex].width);  
                    this.switchTab(this.tabIndex);  
                });  
                // #endif  

            },  
            updateIndicator(left, width) {  
                this.indicatorLineLeft = left;  
                this.indicatorLineWidth = width;  
            },  
            switchTab(index) {  
                if (this.pageList[index].dataList.length === 0) {  
                    this.loadTabData(index);  
                }  

                this.pageList[index].setScrollRef(this._headHeight);  

                if (this.tabIndex === index) {  
                    return;  
                }  

                // 缓存 tabId  
                if (this.pageList[this.tabIndex].dataList.length > MAX_CACHE_DATA) {  
                    let isExist = this.cacheTab.indexOf(this.tabIndex);  
                    if (isExist < 0) {  
                        this.cacheTab.push(this.tabIndex);  
                    }  
                }  

                this.tabIndex = index;  

                // #ifdef APP-NVUE  
                this.scrollTabTo(index);  
                // #endif  
                // #ifndef APP-NVUE  
                this.scrollInto = this.tabList[index].id;  
                // #endif  

                // 释放 tabId  
                if (this.cacheTab.length > MAX_CACHE_PAGE) {  
                    let cacheIndex = this.cacheTab[0];  
                    this.clearTabData(cacheIndex);  
                    this.cacheTab.splice(0, 1);  
                }  
            },  
            scrollTabTo(index) {  
                const el = this.$refs['tabitem' + index][0];  
                let offset = 0;  
                // TODO fix ios offset  
                if (index > 0) {  
                    offset = this.tabbarWidth / 2 - this.tabListSize[index].width / 2;  
                    if (this.tabListSize[index].right < this.tabbarWidth / 2) {  
                        offset = this.tabListSize[0].width;  
                    }  
                }  
                dom.scrollToElement(el, {  
                    offset: -offset  
                });  
            },  
            loadTabData(index) {  
                this.pageList[index].loadData();  
            },  
            clearTabData(index) {  
                this.pageList[index].clear();  
            }  
        }  
    }  
</script>  

<style>  
    /* #ifndef APP-PLUS */  
    page {  
        width: 100%;  
        min-height: 100%;  
        display: flex;  
    }  

    /* #endif */  

    .page {  
        flex: 1;  
    }  

    .header {  
        height: 160px;  
        flex-direction: row;  
        align-items: center;  
        justify-content: center;  
        background-color: #f4f4f4;  
    }  

    .header-title {  
        font-size: 30px;  
        font-weight: bold;  
        color: #444;  
    }  

    .flexible-view {  
        background-color: #f823ff;  
    }  

    .page-head {  
        height: 200px;  
        flex-direction: column;  
        align-items: center;  
        justify-content: center;  
        background-color: red;  
    }  

    .tabs {  
        flex-direction: column;  
        overflow: hidden;  
        background-color: #ffffff;  
        /* #ifdef MP-ALIPAY || MP-BAIDU */  
        height: 100vh;  
        /* #endif */  
    }  

    .tab-bar {  
        width: 750rpx;  
        height: 84rpx;  
        flex-direction: row;  
        /* #ifndef APP-PLUS */  
        white-space: nowrap;  
        /* #endif */  
    }  

    /* #ifndef APP-NVUE */  
    .tab-bar ::-webkit-scrollbar {  
        display: none;  
        width: 0 !important;  
        height: 0 !important;  
        -webkit-appearance: none;  
        background: transparent;  
    }  

    /* #endif */  

    .scroll-view-indicator {  
        position: relative;  
        height: 2px;  
        background-color: transparent;  
    }  

    .scroll-view-underline {  
        position: absolute;  
        top: 0;  
        bottom: 0;  
        width: 0;  
        background-color: #007AFF;  
    }  

    .scroll-view-animation {  
        transition-duration: 0.2s;  
        transition-property: left;  
    }  

    .tab-bar-line {  
        height: 1rpx;  
        background-color: #cccccc;  
    }  

    .tab-view {  
        flex: 1;  
    }  

    .uni-tab-item {  
        /* #ifndef APP-PLUS */  
        display: inline-block;  
        /* #endif */  
        flex-wrap: nowrap;  
        padding-left: 25px;  
        padding-right: 25px;  
    }  

    .uni-tab-item-title {  
        color: #555;  
        font-size: 30rpx;  
        height: 80rpx;  
        line-height: 80rpx;  
        flex-wrap: nowrap;  
        /* #ifndef APP-PLUS */  
        white-space: nowrap;  
        /* #endif */  
    }  

    .uni-tab-item-title-active {  
        color: #007AFF;  
    }  

    .swiper-item {  
        flex: 1;  
        flex-direction: column;  
    }  

    .swiper-page {  
        flex: 1;  
        flex-direction: row;  
        position: absolute;  
        left: 0;  
        top: 0;  
        right: 0;  
        bottom: 0;  
    }  
</style>  

-------------- swiper-page 组件  

<template>  
    <view class="uni-swiper-page">  
        <list ref="list" class="list" :offset-accuracy="5" :bounce="false" fixFreezing="true">  
            <cell v-for="(item, index) in dataList" :key="item.id" :ref="'item'+index">  
                <view class="list-item">  
                    <text>666{{item.name}}</text>  
                </view>  
            </cell>  
            <cell class="loading"></cell>  
        </list>  
    </view>  
</template>  

<script>  
    export default {  
        props: {  
            pid: {  
                type: [Number, String],  
                default: ''  
            },  
            parentId: {  
                type: String,  
                default: ''  
            }  
        },  
        data() {  
            return {  
                scrollable: true,  
                dataList: []  
            }  
        },  
        created() {  
            for (var i = 0; i < 30; i++) {  
                this.dataList.push({  
                    id: i,  
                    name: i  
                });  
            }  
        },  
        methods: {  
            setScrollRef(height) {  
                if (this.$refs['list'].setSpecialEffects) {  
                    this.$refs['list'].setSpecialEffects({  
                        id: this.parentId,  
                        headerHeight: height  
                    });  
                }  
            },  
            loadData() {  
                // 首次激活时被调用  
            },  
            clear() {  
                // 释放数据时被调用，参考 swiper-list 缓存配置  
                this.dataList.length = 0;  
            }  
        }  
    }  
</script>  

<style scoped>  
    .uni-swiper-page {  
        flex: 1;  
        position: absolute;  
        left: 0;  
        top: 0;  
        right: 0;  
        bottom: 0;  
    }  

    .list {  
        flex: 1;  
        background-color: #ebebeb;  
    }  

    .list-item {  
        margin-left: 12px;  
        margin-right: 12px;  
        margin-top: 12px;  
        padding: 20px;  
        background-color: #fff;  
        border-radius: 5px;  
    }  

    .loading {  
        height: 20px;  
    }  
</style>

操作步骤：

在 iOS 上第一个 tab 的内容滚动到下方，第二 tab 滚回到顶部，切换到第一个 tab 滑动，会直接闪一下。

预期结果：

在 iOS 第一个 tab 的内容滚动到下方，第二 tab 滚回到顶部，切换到第一个 tab 滑动，不会闪一下，和安卓一样。

实际结果：

在 iOS 上第一个 tab 的内容滚动到下方，第二 tab 滚回到顶部，切换到第一个 tab 滑动，会直接闪一下。