javascript - Backbone.js DOM 尚未在渲染方法中准备好应用 jquery 魔法

Question

我正在尝试构建一个包含多个列表的待办事项列表。一切正常。当我想使用 JQuery UI Sortable 时，问题就来了。 我在 TaskListView 的渲染函数中添加了代码片段，但我必须将其包装到 setTimeout 函数中，以便它等待 DOM 加载完毕。

我很确定有更好的方法可以做到这一点，但我还没有找到。感谢您的帮助。

var TaskView = Backbone.View.extend({
    initialize: function(task) {
        this.task = task;
    },
    render: function() {
        var completedClass = "completedTask";
        if (this.task.completed == 100) completedClass = "pendingTask";
        var html = ""
        + "<li class='task-<%= task.get('id') %> ' data-id='<%= task.get('id') %>' sortable='true'>"
        + "<div class='float-left'><i class='icon-trash removeTask' data-id='<%= task.get('id') %>'></i></div>"
        + "<div class='float-left'>"
        + "<span class='editTask ' data-type='title' data-id='<%= task.get('id') %>'><%= task.get('title') %></span> "
        + "</div>"
        + "<div class='float-right'>"
        + "<span class='editTask task-responsible label' data-type='responsible' data-id='<%= task.get('id') %>'><%= task.get('responsible') %></span>"
        + "<span class='editTask task-deadline label' data-type='ended' data-id='<%= task.get('id') %>'><%= task.get('ended') %></span>"
        + "<span class='label criticallyLevelToggle editTask <%= criticallyLevelClass %>' data-type='completed' data-id='<%= task.get('id') %>'><%= parseInt(task.get('completed')) %>%</span>"
        + "</div>"
        + "<div class='clear'>&nbsp;</div>"
        +"</li>";

        var template = _.template( html, {task: this.task, criticallyLevelClass:this.task.getCriticallyLevelClass(), completed: completedClass});
        this.$el.html(template);
        return this;
    }
});

var TaskListView = Backbone.View.extend({
    initialize: function(tasks) {
        this.tasks = tasks;
    },
    render: function() {
        var html = ""
        +"<ul class='tasks'>"
        +"<%= tasksli %>"
        +"<li><div class='float-left'><input type='text' placeholder='New task...' class='new-task' name='new-task'/></div><div class='clear'>&nbsp;</div></li>"
        +"</ul>";
        + "";
        var tasksRendered = "";
        if (_.isArray(this.tasks)) {
            for (var i = 0; i < this.tasks.length; i++) {
                var tView = new TaskView(new Task(this.tasks[i]));
                tasksRendered += tView.render().el.innerHTML;
            };
        }
        var template = _.template(html, { tasksli: tasksRendered});
        this.$el.html(template);

        setTimeout(function(){this.$('.tasks').sortable({
            stop: function(e, ui) {
                ui.item.trigger('drop', ui.item.index());
            }
        });}, 500);

        return this;
    }
});

Answer 1

不用setTimeout，只需使用$(function () { })(或$(document).ready)通常等待 DOM 准备就绪。这些函数没有什么特别之处，您可以随时向它们添加新的回调。您只需担心在回调中维护 this 的含义。

render: function() {
    var html = ""
    +"<ul class='tasks'>"
    +"<%= tasksli %>"
    +"<li><div class='float-left'><input type='text' placeholder='New task...' class='new-task' name='new-task'/></div><div class='clear'>&nbsp;</div></li>"
    +"</ul>";
    + "";
    var tasksRendered = "";
    if (_.isArray(this.tasks)) {
        for (var i = 0; i < this.tasks.length; i++) {
            var tView = new TaskView(new Task(this.tasks[i]));
            tasksRendered += tView.render().el.innerHTML;
        };
    }
    var template = _.template(html, { tasksli: tasksRendered});
    this.$el.html(template);
    var self = this;

    $(function(){
        self.$('.tasks').sortable({
        stop: function(e, ui) {
            ui.item.trigger('drop', ui.item.index());
        }
    })

    return this;
}

或者，(可能更正确)采取措施确保您的主干 View 在 DOM 准备就绪之前不会调用其 render 方法。