APICloud AVM框架列表组件list-view的使用、flex布局教程
作者：互联网
avm.js 是APICloud 推出的多端开发框架。使用 avm.js 一个技术栈可同时开发 Android & iOS 原生 App、小程序和 iOS 轻 App，且多端渲染效果统一；全新的 App 引擎 3.0 不依赖 webView，提供百分百的原生渲染，保障 App 性能和体验与原生 App 一致。
list-view 定义可复用内容的竖向滚动视图，可以优化内存占用和渲染性能，支持下拉刷新和上拉加载。可使用 scroll-view 的基本属性。
list-view 里面可放置 cell、list-header、list-footer、refresh 等组件，使用 cell 组件作为每项显示内容。
下面看一个list-view的示例：
<template>
<list-view id="listView" class="main" enable-back-to-top onscrolltolower={this.onscrolltolower}>
<cell class="cell c-lc-rl_ac c-sy-border_bottom c-lc-ptb" onclick={this.itemClick}>
<img class="img" src={item.url} alt="">
<text class="title c-filling-w c-pl">{item.title}</text>
</cell>
<list-footer class="footer">
<text>加载中...</text>
</list-footer>
</list-view>
</template>
<style src='../../css/c-layout-mini.css' scoped>
</style>
<style>
.main {
width: 100%;
height: 100%;
}
.cell {
width: 100%;
height: 70px;
}
.img {
height: 50px;
width: 50px;
margin-left: 10px;
}
.title {
height: 50px;
font-size: 20px;
line-height: 50px;
}
.footer {
justify-content: center;
align-items: center;
}
</style>
<script>
export default {
name: 'test',
methods: {
apiready() {
this.initData(false);
},
initData(loadMore) {
var that = this;
var skip = that.dataList ? that.dataList.length : 0;
var dataList = [];
for (var i = 0; i < 20; i++) {
dataList[i] = {
title: '项目' + (i + skip),
url: '../../image/nav_tab_2.png'
}
}
var listView = document.getElementById('listView');
if (loadMore) {
that.dataList = that.dataList.concat(dataList);
listView.insert({
data: dataList
});
} else {
that.dataList = dataList;
listView.load({
data: dataList
});
}
},
onscrolltolower() {
this.initData(true);
},
itemClick(e) {
api.alert({
msg: '当前项索引：' + e.currentTarget.index
});
}
}
}
</script>
效果如下图：
list-view 只支持APP，需要用自定义loader或APPloader 调试。调试教程可查看文档APICloud Studio3 WiFi真机同步和WiFi真机预览使用说明
list-view 自带内存回收功能，可以滚动加载更多。
给list-view 添加下拉刷新组件 refresh
根据refresh 组件文档，把 refresh 标签添加到 list-view 标签中，如下:
<template>
<list-view id="listView" class="main" enable-back-to-top onscrolltolower={this.onscrolltolower}>
<refresh class="refresh" state={refreshState} onstatechange={this.onstatechange}>
<image class={refreshIconClass} src="../../image/refresh.png"></image>
<image class={refreshLoadingClass} src="../../image/loading_more.gif"></image>
<text class="refreshStateDesc">{refreshStateDesc}</text>
</refresh>
<cell class="cell c-lc-rl_ac c-sy-border_bottom c-lc-ptb" onclick={this.itemClick}>
<img class="img" src={item.url} alt="">
<text class="title c-filling-w c-pl">{item.title}</text>
</cell>
<list-footer class="footer">
<text>加载中...</text>
</list-footer>
</list-view>
</template>
把refresh 组件的css ，js 代码也复制到相应的style 和 script 标签中，并在项目目录image 标签下添加用到的两张下拉刷新图片。完整代码如下：
<template>
<list-view id="listView" class="main" enable-back-to-top onscrolltolower={this.onscrolltolower}>
<refresh class="refresh" state={refreshState} onstatechange={this.onstatechange}>
<image class={refreshIconClass} src="../../image/refresh.png"></image>
<image class={refreshLoadingClass} src="../../image/loading_more.gif"></image>
<text class="refreshStateDesc">{refreshStateDesc}</text>
</refresh>
<cell class="cell c-lc-rl_ac c-sy-border_bottom c-lc-ptb" onclick={this.itemClick}>
<img class="img" src={item.url} alt="">
<text class="title c-filling-w c-pl">{item.title}</text>
</cell>
<list-footer class="footer">
<text>加载中...</text>
</list-footer>
</list-view>
</template>
<style src='../../css/c-layout-mini.css' scoped>
</style>
<style>
.main {
width: 100%;
height: 100%;
}
.cell{
width: 100%;
height: 70px;
}
.img{
height: 50px;
width: 50px;
margin-left: 10px;
}
.title {
height: 50px;
font-size: 20px;
line-height: 50px;
}
.footer {
justify-content: center;
align-items: center;
}
.refresh {
align-items: center;
justify-content: center;
background-color: #eee;
}
.refreshStateDesc {
color: #e3007f;
font-size: 13px;
}
.refreshIcon {
position: absolute;
width: 25px;
height: 22px;
bottom: 21px;
left: 70px;
transition-property: transform;
transition-duration: 100ms;
}
.refreshIcon-normal {
transform: rotate(0);
visibility: visible;
}
.refreshIcon-dragging {
transform: rotate(180deg);
visibility: visible;
}
.refreshIcon-refreshing {
visibility: hidden;
}
.refreshLoading {
position: absolute;
width: 22px;
height: 22px;
bottom: 21px;
left: 70px;
visibility: hidden;
}
.refreshLoading-refreshing {
visibility: visible;
}
</style>
<script>
export default {
name: 'test',
data(){
return {
refreshState: 'normal'
}
},
computed: {
refreshIconClass(){
if (this.data.refreshState == 'normal') {
return 'refreshIcon refreshIcon-normal';
} else if (this.data.refreshState == 'dragging') {
return 'refreshIcon refreshIcon-dragging';
} else if (this.data.refreshState == 'refreshing') {
return 'refreshIcon refreshIcon-refreshing';
}
},
refreshLoadingClass() {
if (this.data.refreshState == 'refreshing') {
return 'refreshLoading refreshLoading-refreshing';
} else {
return 'refreshLoading';
}
},
refreshStateDesc() {
if (this.data.refreshState == 'normal') {
return '下拉可以刷新';
} else if (this.data.refreshState == 'dragging') {
return '松开可以刷新';
} else if (this.data.refreshState == 'refreshing') {
return '刷新中...';
}
}
},
methods:{
apiready() {
this.initData(false);
},
initData(loadMore) {
var that = this;
var skip = that.dataList?that.dataList.length:0;
var dataList = [];
for (var i=0;i<20;i++) {
dataList[i] = {
title: '项目' + (i + skip),
url: '../../image/nav_tab_2.png'
}
}
var listView = document.getElementById('listView');
if (loadMore) {
that.dataList = that.dataList.concat(dataList);
listView.insert({
data: dataList
});
} else {
that.dataList = dataList;
listView.load({
data: dataList
});
}
},
onscrolltolower() {
this.initData(true);
},
itemClick(e) {
api.alert({
msg: '当前项索引：' + e.currentTarget.index
});
},
onstatechange(e) {
var state = e.detail.state;
if (state == 'normal') {
this.data.refreshState = 'normal';
} else if (state == 'dragging') {
this.data.refreshState = 'dragging';
} else if (state == 'refreshing') {
this.data.refreshState = 'refreshing';
var that = this;
setTimeout(function(){
that.data.refreshState = 'normal';
}, 2000);
}
}
}
}
</script>
wi-fi 同步到手机 loader，下拉页面，运行效果如下：
Flex 布局介绍：
Flex 布局意思是弹性盒子布局，比较适合移动端场景，适配不同屏幕大小。
<div> <div>item</div> <div>item</div> <div>item</div> </div>
通常可以把父元素定义为弹性盒子或称为容器，其子元素为弹性盒子的项目。flex布局的主要功能是在主轴或交叉轴按预期排列分布项目，定义每个项目占用空间比例，并可跟随容器大小伸缩。
上图引自下面这篇博客，推荐阅读：
http://www.ruanyifeng.com/blog/2015/07/flex-grammar.html
推荐一个flex git:
https://gitee.com/jiang_xincheng/c-layout
标签：flex,APICloud,return,dataList,list,height,refreshIcon,data 来源： https://www.cnblogs.com/fc-uz/p/15846698.html