Knockout学习之Single Page Application
这篇通过一个带导航栏的邮件应用来学习单页应用
1.添加一个ul标签，通过foreach绑定上数据集合
2.在ul中添加li标签，因为ul上绑定的数据是数组，所以在li上绑定方式要用
data-bind="text:$data"
3.既然是导航，就应该可选择，即点击之后样式要变化，并且有特定时间。
先通过改变class的方式处理样式变化。class的属性名比较奇怪，居然是css。
data-bind="css:{selectedClass: (判断语句)}"
点击时，获取数据并替换绑定的数据，这样与之相关的View就会更新。
注：table绑定chosenFolderData时用到了with绑定。这与其他语言中的with是一样的意思。
在这里，它创建了一个绑定上下文，在该table下绑定到chosenFolderData的元素都不需要添加前缀chosenFolderData
例如mails的绑定。
4.最后再添加上初始化数据：默认选中某个选项(如Inbox).
<!DOCTYPE HTML> <html> <head> <title>Single Page Application</title> <script src="../JS/jquery-latest.min.js" type="text/javascript"></script> <script src="knockout-2.2.0.js" type="text/javascript"></script> <script src="mailsData.js" type="text/javascript"></script> <style type="text/css"> body { font-family: Helvetica, Arial } input:not([type]), input[type=text], input[type=password], select { background-color: #FFFFCC; border: 1px solid gray; padding: 2px; } .folders { background-color: #bbb; list-style-type: none; padding: 0; margin: 0; border-radius: 7px; background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0, #d6d6d6), color-stop(0.4, #c0c0c0), color-stop(1,#a4a4a4)); margin: 10px 0 16px 0; font-size: 0px; } .folders li:hover { background-color: #ddd; } .folders li:first-child { border-left: none; border-radius: 7px 0 0 7px; } .folders li { font-size: 16px; font-weight: bold; display: inline-block; padding: 0.5em 1.5em; cursor: pointer; color: #444; text-shadow: #f7f7f7 0 1px 1px; border-left: 1px solid #ddd; border-right: 1px solid #888; } .folders li { *display: inline !important; } /* IE7 only */ .folders .selected { background-color: #444 !important; color: white; text-shadow:none; border-right-color: #aaa; border-left: none; box-shadow:inset 1px 2px 6px #070707; } .mails { width: 100%; table-layout:fixed; border-spacing: 0; } .mails thead { background-color: #bbb; font-weight: bold; color: #444; text-shadow: #f7f7f7 0 1px 1px; } .mails tbody tr:hover { cursor: pointer; background-color: #68c !important; color: White; } .mails th, .mails td { text-align:left; padding: 0.4em 0.3em; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; } .mails th { border-left: 1px solid #ddd; border-right: 1px solid #888; padding: 0.4em 0 0.3em 0.7em; } .mails th:nth-child(1), .mails td:nth-child(1) { width: 20%; } .mails th:nth-child(2), .mails td:nth-child(2) { width: 15%; } .mails th:nth-child(3), .mails td:nth-child(3) { width: 45%; } .mails th:nth-child(4), .mails td:nth-child(4) { width: 15%; } .mails th:last-child { border-right: none } .mails tr:nth-child(even) { background-color: #EEE; } .viewMail .mailInfo { background-color: #dae0e8; padding: 1em 1em 0.5em 1.25em; border-radius: 1em; } .viewMail .mailInfo h1 { margin-top: 0.2em; font-size: 130%; } .viewMail .mailInfo label { color: #777; font-weight: bold; min-width: 2.75em; text-align:right; display: inline-block; } .viewMail .message { padding: 0 1.25em; } </style> </head> <body> <ul class="folders" data-bind="foreach:folders"> <!--这里有个特殊的属性css 注意它不是样式表的意思，而是class的简写 在这里的意思是，当后面的判断为true时，添加class = selected --> <li data-bind="text:$data ,click:$root.goToFolder ,css:{selected:($data == $root.chosenFolderId())} "></li> </ul> <table class="mails" data-bind="with:chosenFolderData"> <thead> <tr><th>From</th><th>To</th><th>Subject</th> <th>Date</th></tr> </thead> <tbody data-bind="foreach:mails"> <tr> <td data-bind="text:from"></td> <td data-bind="text:to"></td> <td data-bind="text:subject"></td> <td data-bind="text:date"></td> </tr> </tbody> </table> <script type="text/javascript"> function WebmailViewModel() { //Data var self = this; self.folders = ["Inbox", "Archive", "Sent", "Spam"]; self.chosenFolderId = ko.observable(); self.chosenFolderData = ko.observable(); //Behavior self.goToFolder = function(folder) { self.chosenFolderId(folder); //这里应该是用Ajax从Server获取数据，为了方便，我们就把直接它放到变量里吧 //获得的是普通的JSON格式数据 //$.get("http://learn.knockoutjs.com/mail", { folder: folder }, self.chosenFolderData); self.chosenFolderData(mailsData[folder]); }; //Show Inbox By Default. self.goToFolder("Inbox"); } ko.applyBindings(new WebmailViewModel()); </script> </body> </html>
添加查看个人邮件功能
用户现在可以在各文件夹(导航)间切换。还欠缺个读取邮件的功能。
好吧，让我们着手定义一个ViewModel属性来把绑定到邮件的数据显示出来。
在WebmailViewModel里添加
self.chosenMailData = ko.observable();
接下来需要更新我们之前绑定的元素，以便用户点击某一个邮件时，ViewModel会加载响应的邮件信息。
那么，首先在<tr>元素上绑定click
<tr data-bind="click:$root.goToMail">
然后在WebmailViewModel中实现goToMail方法。
self.goToMail = function(mail) { self.chosenFolderId(mail.folder); self.chosenFolderData(null); $.get("/mail", { mailId: mail.id }, self.chosenFolderData); };
最后再把chosenMilData绑定到元素上就能够显示出来了。
<div class = "viewMail" data-bind="with:chosenMailData"> <div class="mailInfo> <h1 data-bind="text:subject"></h1> <p><label>From</label>:<span data-bind="text:from"></span></p> <p><label>To</label>:<span data-bind="text:to"></span></p> <p><label>Date</label>:<span data-bind="text:Date"></span></p> </div> <p class="message" data-bind="html:messageContent"></p> </div>
大功告成。现在点击一条邮件的话，页面上就会显示该邮件的详细信息。
注意一下html绑定的用法。
<p class="message" data-bind="html:messageContent"></p>
它相当于是用p.innerHTML = messageContent
所以要用这个标签绑定数据时，一定要先确定服务器端不会给你发来恶意代码。
还有Demo的效果如此漂亮是因为页面上有良好的CSS代码(Copy from Knockout official Demo)
Knockout.js本身不提供UI效果
<!DOCTYPE HTML> <html> <head> <title>Single Page Application</title> <script src="../JS/jquery-latest.min.js" type="text/javascript"></script> <script src="knockout-2.2.0.js" type="text/javascript"></script> <script src="mailsData.js" type="text/javascript"></script> <style type="text/css"> body { font-family: Helvetica, Arial } input:not([type]), input[type=text], input[type=password], select { background-color: #FFFFCC; border: 1px solid gray; padding: 2px; } body { font-family: Helvetica, Arial} .folders { background-color: #bbb; list-style-type: none; padding: 0; margin: 0; border-radius: 7px; background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0, #d6d6d6), color-stop(0.4, #c0c0c0), color-stop(1,#a4a4a4)); margin: 10px 0 16px 0; font-size: 0px; } .folders li:hover { background-color: #ddd; } .folders li:first-child { border-left: none; border-radius: 7px 0 0 7px; } .folders li { font-size: 16px; font-weight: bold; display: inline-block; padding: 0.5em 1.5em; cursor: pointer; color: #444; text-shadow: #f7f7f7 0 1px 1px; border-left: 1px solid #ddd; border-right: 1px solid #888; } .folders li { *display: inline !important; } /* IE7 only */ .folders .selected { background-color: #444 !important; color: white; text-shadow:none; border-right-color: #aaa; border-left: none; box-shadow:inset 1px 2px 6px #070707; } .mails { width: 100%; table-layout:fixed; border-spacing: 0; } .mails thead { background-color: #bbb; font-weight: bold; color: #444; text-shadow: #f7f7f7 0 1px 1px; } .mails tbody tr:hover { cursor: pointer; background-color: #68c !important; color: White; } .mails th, .mails td { text-align:left; padding: 0.4em 0.3em; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; } .mails th { border-left: 1px solid #ddd; border-right: 1px solid #888; padding: 0.4em 0 0.3em 0.7em; } .mails th:nth-child(1), .mails td:nth-child(1) { width: 20%; } .mails th:nth-child(2), .mails td:nth-child(2) { width: 15%; } .mails th:nth-child(3), .mails td:nth-child(3) { width: 45%; } .mails th:nth-child(4), .mails td:nth-child(4) { width: 15%; } .mails th:last-child { border-right: none } .mails tr:nth-child(even) { background-color: #EEE; } .viewMail .mailInfo { background-color: #dae0e8; padding: 1em 1em 0.5em 1.25em; border-radius: 1em; } .viewMail .mailInfo h1 { margin-top: 0.2em; font-size: 130%; } .viewMail .mailInfo label { color: #777; font-weight: bold; min-width: 2.75em; text-align:right; display: inline-block; } .viewMail .message { padding: 0 1.25em; } </style> </head> <body> <!--Folders--> <ul class="folders" data-bind="foreach:folders"> <!--这里有个特殊的属性css 注意它不是样式表的意思，而是class的简写 在这里的意思是，当后面的判断为true时，添加class = selected --> <li data-bind="text:$data ,click:$root.goToFolder ,css:{selected:($data == $root.chosenFolderId())} "></li> </ul> <!--Mails Grid--> <table class="mails" data-bind="with:chosenFolderData"> <thead> <tr><th>From</th><th>To</th><th>Subject</th> <th>Date</th></tr> </thead> <tbody data-bind="foreach:mails"> <tr data-bind="click:$root.goToMail"> <td data-bind="text:from"></td> <td data-bind="text:to"></td> <td data-bind="text:subject"></td> <td data-bind="text:date"></td> </tr> </tbody> </table> <!--Chosen Mail--> <div class = "viewMail" data-bind="with:chosenMailData"> <div class="mailInfo"> <h1 data-bind="text:subject"></h1> <p><label>From:</label><span data-bind="text:from"></span></p> <p><label>To:</label><span data-bind="text:to"></span></p> <p><label>Date:</label><span data-bind="text:date"></span></p> </div> <p class="message" data-bind="html:messageContent"></p> </div> <script type="text/javascript"> function WebmailViewModel() { //Data var self = this; self.folders = ["Inbox", "Archive", "Sent", "Spam"]; //选中的文件夹 self.chosenFolderId = ko.observable(); //文件夹中的邮件数据 self.chosenFolderData = ko.observable(); //邮件中的数据(From,To,Subject,Date..) self.chosenMailData = ko.observable(); //Behavior self.goToFolder = function(folder) { self.chosenFolderId(folder); //更换Folder时，清空邮件信息 self.chosenMailData(null); //这里应该是用Ajax从Server获取数据，为了方便，我们就把直接它放到变量里吧 //获得的是普通的JSON格式数据 //$.get("http://learn.knockoutjs.com/mail", { folder: folder }, self.chosenFolderData); self.chosenFolderData(mailsData[folder]); }; self.goToMail = function(mail) { self.chosenFolderId(mail.folder); //清空文件夹内所有邮件，以在页面上隐藏邮件信息 self.chosenFolderData(null); //暂且用全局变量来替代。 self.chosenMailData(mailData[Number(mail.id) % 3]); //$.get("http://learn.knockoutjs.com/mail", { mailId: mail.id }, self.chosenFolderData); }; //Show Inbox By Default. self.goToFolder("Inbox"); } ko.applyBindings(new WebmailViewModel()); </script> </body> </html>