iOS跳转到含有不同UINavigationItem的ViewC

想实现这样跳转方法，原本就知道两个UINavigationController不能相互跳转，并且也懒得做自定义modal跳转动画，于是研究了三个小时总算有了两种实现方法

简书APP PUSH跳转 简书APP PUSH跳转

第一种：在viewWillAppear中设置nav bar的隐藏与显示

1. 在AppDelegate中设置rootVC为含有nav的ViewController

self.window = UIWindow(frame: UIScreen.mainScreen().bounds)
self.window?.makeKeyAndVisible()
let vc = ViewController()
self.window?.rootViewController = UINavigationController(rootViewController: vc)

2. ViewController：
   在viewWillAppear中设置nav bar的隐藏

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)
    // 动画必须设置为true，否则会导致转场动画是nav bar不显示
    self.navigationController?.setNavigationBarHidden(true, animated: true) 
}

随意添加一个按钮实现跳转

屏幕快照 2016-05-19 下午7.01.08.png

3. 在SecondViewController中设置显示nav bar
   同样在viewWillAppear设置nav bar为显示

override func viewDidLoad() {
    super.viewDidLoad()
    self.view.backgroundColor = UIColor.whiteColor()
    
    self.navigationItem.title = "首页"
   
    // 最好不要设置leftBarButton，会导致pop手势失效
    // self.navigationItem.leftBarButtonItem = UIBarButtonItem(title: "下一页", style: .Done, target: self, action: #selector(self.returnAction))
}
override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)
    self.navigationController?.setNavigationBarHidden(false, animated: true)
}

这样就实现了从无item到有item的跳转：

1.gif

4. 在ViewController中添加一个自定义的UINavigationBar

    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.backgroundColor = UIColor.whiteColor()
        // 一定要设置nav的view的颜色，否则在跳转时自定义的bar右上角会有黑色。但是如果将自定义的bar设置为其他View（比如UIView）就不会有这种现象
        self.navigationController?.view.backgroundColor = UIColor.whiteColor()
        
        let customBar = UINavigationBar(frame: CGRectMake(0, 0, self.view.frame.width, 64))
        self.view.addSubview(customBar)
        
        let customItem = UINavigationItem(title: "首页")
        customItem.leftBarButtonItem = UIBarButtonItem(title: "进入", style: .Done, target: self, action: #selector(self.next))
        customBar.items = [customItem]
}

效果：

2.gif

第二种：封装基类，直接隐藏掉nav bar，添加一个自定义的bar，继承基类即会实现该效果，方便使用

BaseViewController：

class BaseViewController: UIViewController {
    
    // 使用自定义的navigationItem
    // 不能使用原本的navigationItem，当pop回来后里面的item会消失，可能和生命周期有关，不知道它都干了些什么
    var customNavigationItem = UINavigationItem(title: "")
    
    // 怎么私有化navigationItem啊！！这样会失败
//    override private var navigationItem: UINavigationItem
//    override private var navigationItem: UINavigationItem
//    override private var navigationItem: UINavigationItem
//    override private var navigationItem: UINavigationItem {
//        get{
//            return self.navigationItem
//        }
//    }

    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.backgroundColor = UIColor.whiteColor()
        // 隐藏原本的nav
        self.navigationController?.view.backgroundColor = UIColor.whiteColor() // 需要设置点颜色，否则push时右上角会显示一段黑色
        // 必须设置这两个属性，否则会导致pop手势失效
        self.navigationController?.navigationBar.shadowImage = UIImage()
        self.navigationController?.navigationBar.setBackgroundImage(UIImage(), forBarMetrics: .Default)
        self.navigationController?.navigationBar.hidden = true

        // 不能使用这个方法，会导致pop手势失效，也不能把bar removeFromSuperView
//        self.navigationController?.setNavigationBarHidden(true, animated: true)
        
        // 自定义的nav bar，直接加到view上
        let customBar = UINavigationBar(frame: CGRectMake(0, 0, self.view.frame.width, 64))
        self.view.addSubview(customBar)
        
        // 设置item
        customBar.items = [customNavigationItem]
    }
}

使用：
ViewController：

class ViewController: BaseViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        
        self.customNavigationItem.title = "首页"
        self.customNavigationItem.leftBarButtonItem = UIBarButtonItem(title: "下一页", style: .Done, target: self, action: #selector(self.next))
    }
    
    func next() {
        let sec = SecondViewController()
        self.navigationController?.pushViewController(sec, animated: true)
    }
}

SecondViewCotroller：

class SecondViewController: BaseViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.backgroundColor = UIColor.whiteColor()
        
        self.customNavigationItem.title = "第二页"
        self.customNavigationItem.leftBarButtonItem = UIBarButtonItem(title: "返回", style: .Done, target: self, action: #selector(self.returnAction))
    }
    
    func returnAction() {
        self.navigationController?.popViewControllerAnimated(true)
    }
}

效果：

3.gif