使用滑动手势在标签栏之间导航答案

【问题标题】：navigate between tab bar using swipe gesture使用滑动手势在标签栏之间导航
【发布时间】：2017-05-28 20:35:51
【问题描述】：

我想使用滑动手势在标签栏之间导航。最简单的方法是什么？我尝试过这样的事情......

import UIKit

class postAdViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        var leftSwipe = UISwipeGestureRecognizer(target: self, action: Selector("handleSwipes:"))
        view.addGestureRecognizer(leftSwipe)    
    }

    func handleSwipes(sender:UISwipeGestureRecognizer) {
        if (sender.direction == .left) {
            let storyboard = UIStoryboard(name: "Main", bundle: nil)
            let vc = storyboard.instantiateViewController(withIdentifier: "favourireviewcontroller") as! UIViewController
            self.present(vc, animated: true, completion: nil)
        }
        if (sender.direction == .right) {

        }
}

如果我尝试向右滑动，则没有任何反应。滑动时应用崩溃并留下以下错误消息

无法识别的选择器发送到实例 0x7f924380a730

【问题讨论】：

标签： ios swift swift3 xcode8 swipe

【解决方案1】：

如果你想在tabBar 中导航，你应该为.left 和.right 实现swipeGestureRecognizer，然后使用tabBarController?.selectedIndex，如下所示：

let swipeRight = UISwipeGestureRecognizer(target: self, action: #selector(swiped))
swipeRight.direction = UISwipeGestureRecognizerDirection.right
self.view.addGestureRecognizer(swipeRight)

let swipeLeft = UISwipeGestureRecognizer(target: self, action: #selector(swiped))
swipeLeft.direction = UISwipeGestureRecognizerDirection.left
self.view.addGestureRecognizer(swipeLeft)

func swiped(_ gesture: UISwipeGestureRecognizer) {
    if gesture.direction == .left {
        if (self.tabBarController?.selectedIndex)! < 2 { // set your total tabs here
            self.tabBarController?.selectedIndex += 1
        }
    } else if gesture.direction == .right {
        if (self.tabBarController?.selectedIndex)! > 0 {
            self.tabBarController?.selectedIndex -= 1
        }
    }
}

【讨论】：

【解决方案2】：

这是一个在 TabBar 控制器中左右滑动的 Swift4 示例。

我不喜欢这个解决方案的地方： - 似乎您应该能够注册一次处理程序并区分处理程序本身的方向，但我无法轻松做到这一点。 - 我也很好奇如何做一个包含拖动视觉效果的手势。我认为我还需要包含一个 PanGesture 才能实现这一目标。

override func viewDidLoad() {
    super.viewDidLoad()

    let leftSwipe = UISwipeGestureRecognizer(target: self, action: #selector(handleSwipes(_:)))
    let rightSwipe = UISwipeGestureRecognizer(target: self, action: #selector(handleSwipes(_:)))
    leftSwipe.direction = .left
    rightSwipe.direction = .right
    self.view.addGestureRecognizer(leftSwipe)
    self.view.addGestureRecognizer(rightSwipe)

}

然后是处理程序：

@objc func handleSwipes(_ sender:UISwipeGestureRecognizer) {
    if sender.direction == .left {
        self.tabBarController!.selectedIndex += 1
    }
    if sender.direction == .right {
        self.tabBarController!.selectedIndex -= 1
    }
}

【讨论】：

【解决方案3】：

这是对早期建议稍作修改的版本，适用于 Swift 5 和 iOS 12。

真正的优势是：

它使用guard 语句，因此您不必在处理程序中解开tabBarController 和viewControllers
它不需要硬编码的选项卡数量 - 它只是从 viewControllers 数组中获取它。

我还对其进行了一些清理以使其不那么冗长。它已经在 iOS 12 上运行 Swift 5 进行了测试（在 iOS 11.4 上应该没问题，因为这是我测试过的最低部署版本）。

将这些添加到viewDidLoad（或您选择的其他适当位置）：

let swipeRight = UISwipeGestureRecognizer(target: self, action: #selector(handleSwipeGesture))
swipeRight.direction = .right
self.view.addGestureRecognizer(swipeRight)

let swipeLeft = UISwipeGestureRecognizer(target: self, action: #selector(handleSwipeGesture))
swipeLeft.direction = .left
self.view.addGestureRecognizer(swipeLeft)

然后将其添加为事件的处理程序：

@objc func handleSwipeGesture(_ gesture: UISwipeGestureRecognizer) {
  guard let tabBarController = tabBarController, let viewControllers = tabBarController.viewControllers else { return }
  let tabs = viewControllers.count        
  if gesture.direction == .left {
      if (tabBarController.selectedIndex) < tabs {
          tabBarController.selectedIndex += 1
      }
  } else if gesture.direction == .right {
      if (tabBarController.selectedIndex) > 0 {
          tabBarController.selectedIndex -= 1
      }
  }
}

【讨论】：

感谢代码，滑动不是动画，你知道如何动画吗？

【解决方案4】：

尝试使用 Swift 4 选择器语法：

//below code write in view did appear()
let swipeRight = UISwipeGestureRecognizer(target: self, action:  #selector(swiped))
    swipeRight.direction = UISwipeGestureRecognizerDirection.right
    self.view.addGestureRecognizer(swipeRight)

    let swipeLeft = UISwipeGestureRecognizer(target: self, action: #selector(swiped))
    swipeLeft.direction = UISwipeGestureRecognizerDirection.left
    self.view.addGestureRecognizer(swipeLeft)
  // below code create swipe gestures function

  // MARK: - swiped
   @objc  func swiped(_ gesture: UISwipeGestureRecognizer) {
    if gesture.direction == .left {
        if (self.tabBarController?.selectedIndex)! < 2
        { // set here  your total tabs
            self.tabBarController?.selectedIndex += 1
        }
    } else if gesture.direction == .right {
        if (self.tabBarController?.selectedIndex)! > 0 {
            self.tabBarController?.selectedIndex -= 1
        }
    }
}

【讨论】：

【解决方案5】：

尝试使用Swift 3 选择器语法：

let leftSwipe = UISwipeGestureRecognizer(target: self, action: #selector(handleSwipes(_:))

像这样

override func viewDidLoad() {
    super.viewDidLoad()

    nextButton.layer.cornerRadius = 7

    let leftSwipe = UISwipeGestureRecognizer(target: self, action: #selector(handleSwipes(_:))
    //leftSwipe.direction = .right
    view.addGestureRecognizer(leftSwipe)
}



func handleSwipes(_ sender: UISwipeGestureRecognizer) {
    if (sender.direction == .left) {
        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        let vc = storyboard.instantiateViewController(withIdentifier: "favourireviewcontroller") as! UIViewController
        self.present(vc, animated: true, completion: nil)
    }

    if (sender.direction == .right) {

    }
}

Swift 3 引入了此功能，使编译器能够检查您指定的function 是否确实存在。因此，它比之前的概念要节省很多。

【讨论】：