通过使用导航条（UINavigationBar）与导航条控制器（UINavigationController）可以方便的在主页面和多层子页面之间切换。下面通过一个简单“组件效果演示”的小例子来说明如何通过代码来进行页面的切换。
功能如下：
1，在AppDelagete.swift入口文件中把首页ViewController做了导航控件的封装
2，首页是一个表格列出几个Swift控件的名称
3，点击表格项即切换到对应组件展示页面，顶部的导航条标题变为该控件的名称，同时导航条左侧还有返回按钮
4，在展示页中，给导航条右侧添加了“效果/代码”切换的按钮，点击分别展示组件的效果和代码
效果图如下：
代码如下：
--- 入口文件 AppDelegate.swift ---
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import UIKit
@UIApplicationMainclass AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
func application(application: UIApplication,
didFinishLaunchingWithOptions launchOptions: NSDictionary?) -> Bool {
// Override point for customization after application launch.
// 把起始ViewController作为导航控件封装，我们在ViewController里就能调用导航条进行页面切换了
var rootViewController = ViewController()
var rootNavigationController = UINavigationController(rootViewController: rootViewController)
self.window!.rootViewController = rootNavigationController
return true
}
func applicationWillResignActive(application: UIApplication) {
}
func applicationDidEnterBackground(application: UIApplication) {
}
func applicationWillEnterForeground(application: UIApplication) {
}
func applicationDidBecomeActive(application: UIApplication) {
}
func applicationWillTerminate(application: UIApplication) {
}
} |
--- 主页面 ViewController.swift ---
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import UIKit
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
// 表格加载
var tableView:UITableView?
// 控件类型
var ctrls = ["UILabel", "UIButton", "UIImageView", "UISlider", "UIWebView"]
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.title = "Swift控件演示"
self.tableView = UITableView(frame:self.view.frame, style:UITableViewStyle.Plain)
self.tableView!.delegate = self
self.tableView!.dataSource = self
self.tableView!.registerClass(UITableViewCell.self, forCellReuseIdentifier: "SwiftCell")
self.view.addSubview(self.tableView!)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// UITableViewDataSource协议方法
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{
return self.ctrls.count
}
// UITableViewDataSource协议方法
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath)
-> UITableViewCell
{
let cell = tableView.dequeueReusableCellWithIdentifier("SwiftCell", forIndexPath:indexPath)
as UITableViewCell
cell.accessoryType = UITableViewCellAccessoryType.DisclosureIndicator
cell.textLabel?.text = self.ctrls[indexPath.row]
return cell
}
// UITableViewDelegate协议方法，点击时调用
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath!)
{
// 跳转到detailViewController，取消选中状态
self.tableView!.deselectRowAtIndexPath(indexPath, animated: true)
// 创建DetailViewController
var detailViewController = DetailViewController()
// 传递控件的title，在detailView里用于判断生成响应的控件
detailViewController.title = self.ctrls[indexPath.row]
// navigationController跳转到detailViewController
self.navigationController!.pushViewController(detailViewController, animated:true)
}
} |
--- 子页面 DetailViewController.swift ---
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import UIKit
class DetailViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
//设置背景色
self.view.backgroundColor = UIColor.whiteColor()
//按title加载控件
loadControl(self.title!)
//设置代码和控件展示切换按钮，增加到导航条的右侧
//这里采用了navigationController不能增加navigationItem
let btn = UIBarButtonItem(title:"代码", style: UIBarButtonItemStyle.Bordered,
target: self, action: "btnCodeClicked:")
self.navigationItem.rightBarButtonItem = btn
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
//构建控件并加载到界面
func loadControl(ctrl:String) {
switch (ctrl) {
case "UILabel":
let label = UILabel(frame: self.view.bounds)
label.backgroundColor = UIColor.clearColor()
label.textAlignment = NSTextAlignment.Center
label.font = UIFont.systemFontOfSize(36)
label.text = "Hello, Ucai"
self.view.addSubview(label)
case "UIButton":
var button = UIButton(frame: CGRectMake(110,120,100,60))
button.backgroundColor = UIColor.blueColor()
button.setTitleColor(UIColor.redColor(), forState: UIControlState.Normal)
button.setTitleColor(UIColor.whiteColor(), forState: UIControlState.Highlighted)
button.setTitle("点击我", forState: .Normal)
button.addTarget(self, action: "buttonClicked:",
forControlEvents: UIControlEvents.TouchUpInside)
self.view.addSubview(button)
case "UIImageView":
var image = UIImage(named: "swift.png")
var imageView = UIImageView(frame:
CGRectMake((CGRectGetWidth(self.view.bounds) - image!.size.width) / 2.0, 120.0,
image!.size.width, image!.size.height))
imageView.image = image!
self.view.addSubview(imageView)
case "UISlider":
let slider = UISlider(frame:CGRectMake(60.0, 120.0, 200.0, 30.0))
self.view.addSubview(slider)
case "UIWebView":
var webView = UIWebView(frame:self.view.bounds)
var request = NSURLRequest(URL: url!)
webView.loadRequest(request)
self.view.addSubview(webView)
default:
println("control name: \(ctrl)")
}
}
//显示控件的代码
func loadCode(ctrl:String) {
var str:String
switch (ctrl) {
case "UILabel":
str = "let label = UILabel(frame: self.view.bounds)\n"
str += "label.backgroundColor = UIColor.clearColor()\n"
str += "label.textAlignment = NSTextAlignment.Center\n"
str += "label.font = UIFont.systemFontOfSize(36)\n"
str += "label.text = \"Hello, Ucai\"\n"
str += "self.view.addSubview(label)"
case "UIButton":
str = "UIButton"
case "UISlider":
str = "let slider = UISlider(frame:CGRectMake(60.0, 120.0, 200.0, 30.0))\n"
str += "self.view.addSubview(slider)"
default:
str = "other ctrl"
}
//在导航条下方位置显示源代码
var txt = UITextView(
frame: CGRectMake(0, 60, self.view.bounds.size.width, self.view.bounds.size.height - 60))
txt.text = str
self.view.addSubview(txt)
}
//清空所有子视图
func clearViews() {
for v in self.view.subviews as [UIView] {
v.removeFromSuperview()
}
}
func buttonClicked(sender:AnyObject) {
println("you clicked button")
}
//显示控件的代码
func btnCodeClicked(sender:AnyObject) {
println("title: \(self.title)")
clearViews()
if self.navigationItem.rightBarButtonItem!.title == "代码" {
loadCode(self.title!)
self.navigationItem.rightBarButtonItem!.title = "效果"
}
else {
self.navigationItem.rightBarButtonItem!.title = "代码"
loadControl(self.title!)
}
}
/*
func btnBackClicked(sender:AnyObject) {
self.navigationController.navigationBar.popNavigationItemAnimated(true)
}
*/
} |
如果使用StoryBoard实现更加简单
AppDelegate.swift都不需要修改。打开Main.storyboard。
（1）点击首页的Scene，选择Editor -> Embed In -> Navigation Controller 即可。
（2）从首页单元格拖“show”的关联Segue到详细页，或从首页View Controller拖手动关联Segue到详细页，并定义这个Segue的Indentifier（比如detail）
这样，点击单元格跳转的代码有所改变，是根据刚才定义Segue的Indentifier来跳转
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// UITableViewDelegate协议方法，点击时调用func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath!){ // 跳转到detailViewController，取消选中状态
self.tableView!.deselectRowAtIndexPath(indexPath, animated: true)
//更具定义的Segue Indentifier进行跳转
self.performSegueWithIdentifier("detail", sender: self.ctrls[indexPath.row])
} //在这个方法中给新页面传递参数override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "detail"{
let controller = segue.destinationViewController as! DetailViewController
controller.title = sender as? String
}
} |