MVVM模式不但可用于Form表单,在复杂的管理页面中也能大显身手。例如,分页显示Blog的功能,我们先把后端代码写出来:
在apis.py中定义一个Page类用于存储分页信息:
class Page(object): def __init__(self, item_count, page_index=1, page_size=10): self.item_count = item_count self.page_size = page_size self.page_count = item_count // page_size + (1 if item_count % page_size > 0 else 0) if (item_count == 0) or (page_index > self.page_count): self.offset = 0 self.limit = 0 self.page_index = 1 else: self.page_index = page_index self.offset = self.page_size * (page_index - 1) self.limit = self.page_size self.has_next = self.page_index < self.page_count self.has_previous = self.page_index > 1 def __str__(self): return 'item_count: %s, page_count: %s, page_index: %s, page_size: %s, offset: %s, limit: %s' % (self.item_count, self.page_count, self.page_index, self.page_size, self.offset, self.limit) __repr__ = __str__
在handlers.py中实现API:
@get('/api/blogs') def api_blogs(*, page='1'): page_index = get_page_index(page) num = yield from Blog.findNumber('count(id)') p = Page(num, page_index) if num == 0: return dict(page=p, blogs=()) blogs = yield from Blog.findAll(orderBy='created_at desc', limit=(p.offset, p.limit)) return dict(page=p, blogs=blogs)
管理页面:
@get('/manage/blogs') def manage_blogs(*, page='1'): return { '__template__': 'manage_blogs.html', 'page_index': get_page_index(page) }
模板页面首先通过API:GET /api/blogs?page=?拿到Model:
{ "page": { "has_next": true, "page_index": 1, "page_count": 2, "has_previous": false, "item_count": 12 }, "blogs": [...] }
然后,通过Vue初始化MVVM:
<script> function initVM(data) { var vm = new Vue({ el: '#vm', data: { blogs: data.blogs, page: data.page }, methods: { edit_blog: function (blog) { location.assign('/manage/blogs/edit?id=' + blog.id); }, delete_blog: function (blog) { if (confirm('确认要删除“' + blog.name + '”?删除后不可恢复!')) { postJSON('/api/blogs/' + blog.id + '/delete', function (err, r) { if (err) { return alert(err.message || err.error || err); } refresh(); }); } } } }); $('#vm').show(); } $(function() { getJSON('/api/blogs', { page: {{ page_index }} }, function (err, results) { if (err) { return fatal(err); } $('#loading').hide(); initVM(results); }); }); </script>
View的容器是#vm,包含一个table,我们用v-repeat可以把Model的数组blogs直接变成多行的<tr>:
<div id="vm" class="uk-width-1-1"> <a href="/manage/blogs/create" class="uk-button uk-button-primary"><i class="uk-icon-plus"></i> 新日志</a> <table class="uk-table uk-table-hover"> <thead> <tr> <th class="uk-width-5-10">标题 / 摘要</th> <th class="uk-width-2-10">作者</th> <th class="uk-width-2-10">创建时间</th> <th class="uk-width-1-10">操作</th> </tr> </thead> <tbody> <tr v-repeat="blog: blogs" > <td> <a target="_blank" v-attr="href: '/blog/'+blog.id" v-text="blog.name"></a> </td> <td> <a target="_blank" v-attr="href: '/user/'+blog.user_id" v-text="blog.user_name"></a> </td> <td> <span v-text="blog.created_at.toDateTime()"></span> </td> <td> <a href="#0" v-on="click: edit_blog(blog)"><i class="uk-icon-edit"></i> <a href="#0" v-on="click: delete_blog(blog)"><i class="uk-icon-trash-o"></i> </td> </tr> </tbody> </table> <div v-component="pagination" v-with="page"></div> </div>
往Model的blogs数组中增加一个Blog元素,table就神奇地增加了一行;把blogs数组的某个元素删除,table就神奇地减少了一行。所有复杂的Model-View的映射逻辑全部由MVVM框架完成,我们只需要在HTML中写上v-repeat指令,就什么都不用管了。
可以把v-repeat="blog: blogs"看成循环代码,所以,可以在一个<tr>内部引用循环变量blog。v-text和v-attr指令分别用于生成文本和DOM节点属性。
完整的Blog列表页如下:
参考源码
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