swift - 将选择器 View 返回到先前选择的行

Question

在我的应用程序中，我允许用户通过选择器 View 更改应用程序的颜色主题。在此过程中，栏和按钮等 UI 元素会根据用户的选择进行更改。

当 View 关闭并重新打开时，选择器 View 返回到第一个项目时遇到问题。如何使选择器 View 返回用户之前选择的颜色？

这是我当前用于选择器 View 的代码:

    func numberOfComponentsInPickerView(pickerView: UIPickerView!) -> Int {

    return 1
}

func pickerView(pickerView: UIPickerView!, numberOfRowsInComponent component: Int) -> Int {

    return coloursArray.count
}

func pickerView(pickerView: UIPickerView!, titleForRow row: Int, forComponent component: Int) -> String! {

    return coloursArray[row]
}

func pickerView(pickerView: UIPickerView!, didSelectRow row: Int, inComponent: Int) {
    colourSelected = row
    if colourSelected == 0 {
        self.navigationController.navigationBar.barTintColor = UIColor.newBlueColor()
        self.tabBarController.tabBar.selectedImageTintColor = UIColor.newBlueColor()
        UINavigationBar.appearance().barTintColor = UIColor.newBlueColor()
        UISegmentedControl.appearance().tintColor = UIColor.newBlueColor()
        changeButton.layer.backgroundColor = (UIColor.newBlueColor()).CGColor
    } else if colourSelected == 1 {
        self.navigationController.navigationBar.barTintColor = UIColor.newGreenColor()
        self.tabBarController.tabBar.selectedImageTintColor = UIColor.newGreenColor()
        UINavigationBar.appearance().barTintColor = UIColor.newGreenColor()
        UIButton.appearance().setTitleColor(UIColor.newGreenColor(), forState: UIControlState())
        UISegmentedControl.appearance().tintColor = UIColor.newGreenColor()
        changeButton.layer.backgroundColor = (UIColor.newGreenColor()).CGColor
    } else if colourSelected == 2 {
        self.navigationController.navigationBar.barTintColor = UIColor.newOrangeColor()
        self.tabBarController.tabBar.selectedImageTintColor = UIColor.newOrangeColor()
        UINavigationBar.appearance().barTintColor = UIColor.newOrangeColor()
        UISegmentedControl.appearance().tintColor = UIColor.newOrangeColor()
        changeButton.layer.backgroundColor = (UIColor.newOrangeColor()).CGColor
    } else if colourSelected == 3 {
        self.navigationController.navigationBar.barTintColor = UIColor.newPurpleColor()
        self.tabBarController.tabBar.selectedImageTintColor = UIColor.newPurpleColor()
        UINavigationBar.appearance().barTintColor = UIColor.newPurpleColor()
        UISegmentedControl.appearance().tintColor = UIColor.newPurpleColor()
        changeButton.layer.backgroundColor = (UIColor.newPurpleColor()).CGColor
    } else if colourSelected == 4 {
        self.navigationController.navigationBar.barTintColor = UIColor.newRedColor()
        self.tabBarController.tabBar.selectedImageTintColor = UIColor.newRedColor()
        UINavigationBar.appearance().barTintColor = UIColor.newRedColor()
        UISegmentedControl.appearance().tintColor = UIColor.newRedColor()
        changeButton.layer.backgroundColor = (UIColor.newRedColor()).CGColor
    } else if colourSelected == 5 {
        self.navigationController.navigationBar.barTintColor = UIColor.newTurquoiseColor()
        self.tabBarController.tabBar.selectedImageTintColor = UIColor.newTurquoiseColor()
        UINavigationBar.appearance().barTintColor = UIColor.newTurquoiseColor()
        UISegmentedControl.appearance().tintColor = UIColor.newTurquoiseColor()
        changeButton.layer.backgroundColor = (UIColor.newTurquoiseColor()).CGColor
    }
}

Answer 1

假设您的选择器中有一列(“组件”):

override func viewDidLoad() {
   super.viewDidLoad()
   let idx = NSUserDefaults.standardUserDefaults().integerForKey("SavedIndex")
   pickerView.selectRow(idx, inComponent: 0, animated: false)
}

当然，当选择一行时，保存到 NSUserDefaults。

根据您的设置，您可能需要将其放入 viewWillAppear() 中。