更改UISegmentedControl后如何重载UIViewController？

问题描述 投票：0回答：1

我有一个带有UISegmentedControl的viewController，可以在2个内容之间切换（按部门或按配方）。当我切换segmentedControl时(会执行changeColor函数)，我想改变选择哪个段的对应内容。每个段中的内容都是几个UILabel，然后像view.addSubview(label)一样添加它们。但是，我现在的代码做的是将它们重叠放置。

class GroceryViewController: UIViewController {

    var customSC = UISegmentedControl()

    override func viewDidLoad() {
        super.viewDidLoad()
        setupSegmentedControl()
        contentByDepartment()
    }

    func setupSegmentedControl() {
        let items = ["BY DEPARTMENT", "BY RECIPE"]
        customSC = UISegmentedControl(items: items)
        customSC.selectedSegmentIndex = 0

        let frame = UIScreen.main.bounds
        customSC.frame = CGRect(x:frame.minX + 15, y:frame.minY + 100,
                                width:frame.width - 30, height:frame.height * 0.04)
        customSC.layer.cornerRadius = 20
        customSC.backgroundColor = UIColor(hexString: "#F7F7F7")
        customSC.setTitleTextAttributes([NSAttributedString.Key.foregroundColor: UIColor(hexString: "#FC6A03")], for: UIControl.State.selected)
        customSC.addTarget(self, action: #selector(changeColor), for: .valueChanged)
        view.addSubview(customSC)
    }

    @objc func changeColor(_ sender: UISegmentedControl) {
        switch sender.selectedSegmentIndex {
            case 0:
                contentByDepartment() // contents are several UILabel adding to view as SubView
            case 1:
                contentByRecipe() // contents are several UILabel adding to view as SubView
            default:
                break
        }
    }
}

我找了一下解决办法，大部分都是 "在UITableView中reloadData()"，我没有。所以我不知道如何在不打扰UIView和UITableView的情况下重载这个viewController。

问题是：是否有可能单独从某个函数中重载viewController，这样在显示选中的内容之前，之前的内容就会被清除，以及如何做到这一点？

EDIT：contentByDepartment和contentByRecipe的代码。

func contentByDepartment() {
        let recipeHeader = UILabel(frame: CGRect(x:50, y:180, width: 200, height: 20))
        recipeHeader.setActivityDescription(label: "Coffee and Tea")
        recipeHeader.textColor = UIColor(hexString: "#FC6A03")
        recipeHeader.font = UIFont.systemFont(ofSize: 20)

        let ingredient1Name = UILabel(frame: CGRect(x:70,y:210,width:200,height:20))
        ingredient1Name.setActivityDescription(label: "Green tea leaves")
        ingredient1Name.font = UIFont.systemFont(ofSize: 16)

        let ingredient1Amount = UILabel(frame: CGRect(x:72,y:230,width:200,height:20))
        ingredient1Amount.setActivityDescription(label: "1 tablespoons")
        ingredient1Amount.font = UIFont.systemFont(ofSize: 12)

        let ingredient2Name = UILabel(frame: CGRect(x:70,y:260,width:200,height:20))
        ingredient2Name.setActivityDescription(label: "Coffee powder")
        ingredient2Name.font = UIFont.systemFont(ofSize: 16)

        let ingredient2Amount = UILabel(frame: CGRect(x:72,y:280,width:200,height:20))
        ingredient2Amount.setActivityDescription(label: "3 tablespoons")
        ingredient2Amount.font = UIFont.systemFont(ofSize: 12)

        view.addSubview(recipeHeader)
        view.addSubview(ingredient1Name)
        view.addSubview(ingredient1Amount)
        view.layer.addSublayer(drawLine(x1:70, y1:255, x2:350, y2:255, lineWidth:0.3))
        view.addSubview(ingredient2Name)
        view.addSubview(ingredient2Amount)
        view.layer.addSublayer(drawLine(x1:0, y1:310, x2:420, y2:310, lineWidth:0.5))
}

func contentByRecipe() {
        let recipeHeader = UILabel(frame: CGRect(x:50, y:180, width: 200, height: 20))
        recipeHeader.setActivityDescription(label: "Cha-yen")
        recipeHeader.textColor = UIColor(hexString: "#FC6A03")
        recipeHeader.font = UIFont.systemFont(ofSize: 20)

        let ingredient1Name = UILabel(frame: CGRect(x:70,y:210,width:200,height:20))
        ingredient1Name.setActivityDescription(label: "Vanilla extract")
        ingredient1Name.font = UIFont.systemFont(ofSize: 16)

        let ingredient1Amount = UILabel(frame: CGRect(x:72,y:230,width:200,height:20))
        ingredient1Amount.setActivityDescription(label: "1 tablespoons")
        ingredient1Amount.font = UIFont.systemFont(ofSize: 12)

        let ingredient2Name = UILabel(frame: CGRect(x:70,y:260,width:200,height:20))
        ingredient2Name.setActivityDescription(label: "Sugar")
        ingredient2Name.font = UIFont.systemFont(ofSize: 16)

        let ingredient2Amount = UILabel(frame: CGRect(x:72,y:280,width:200,height:20))
        ingredient2Amount.setActivityDescription(label: "3 tablespoons")
        ingredient2Amount.font = UIFont.systemFont(ofSize: 12)

        view.addSubview(recipeHeader)
        view.addSubview(ingredient1Name)
        view.addSubview(ingredient1Amount)
        view.layer.addSublayer(drawLine(x1:70, y1:255, x2:350, y2:255, lineWidth:0.3))
        view.addSubview(ingredient2Name)
        view.addSubview(ingredient2Amount)
        view.layer.addSublayer(drawLine(x1:0, y1:310, x2:420, y2:310, lineWidth:0.5))
}
swift uiviewcontroller uisegmentedcontrol
1个回答
0
投票

你应该学会把相关的视图组合在一起。现在，你将所有的视图都添加为 view. 这是很没有条理的，导致你现在的情况--不能有效地显示某些视图。

组织视图的一种方法是将 "按部门 "的视图添加到一个大的 UIView和所有 "按配方 "的观点到另一个大的。UIView.

var byDepartmentContainerView: UIView!
func setUpContentByDepartment() {
    let recipeHeader = UILabel(frame: ...)
    recipeHeader.setActivityDescription(label: "Coffee and Tea")
    recipeHeader.textColor = UIColor(hexString: "#FC6A03")
    recipeHeader.font = UIFont.systemFont(ofSize: 20)

    let ingredient1Name = UILabel(frame: ...)
    ingredient1Name.setActivityDescription(label: "Green tea leaves")
    ingredient1Name.font = UIFont.systemFont(ofSize: 16)

    let ingredient1Amount = UILabel(frame: ...)
    ingredient1Amount.setActivityDescription(label: "1 tablespoons")
    ingredient1Amount.font = UIFont.systemFont(ofSize: 12)

    let ingredient2Name = UILabel(frame: ...)
    ingredient2Name.setActivityDescription(label: "Coffee powder")
    ingredient2Name.font = UIFont.systemFont(ofSize: 16)

    let ingredient2Amount = UILabel(frame: ...)
    ingredient2Amount.setActivityDescription(label: "3 tablespoons")
    ingredient2Amount.font = UIFont.systemFont(ofSize: 12)

    byDepartmentContainerView = UIView(frame: ...)

    byDepartmentContainerView.addSubview(recipeHeader)
    byDepartmentContainerView.addSubview(ingredient1Name)
    byDepartmentContainerView.addSubview(ingredient1Amount)
    byDepartmentContainerView.addSubview(ingredient2Name)
    byDepartmentContainerView.addSubview(ingredient2Amount)
}

var byRecipeContainerView: UIView!
func setUpContentByRecipe() {
    let recipeHeader = UILabel(frame: CGRect(x:50, y:180, width: 200, height: 20))
    recipeHeader.setActivityDescription(label: "Cha-yen")
    recipeHeader.textColor = UIColor(hexString: "#FC6A03")
    recipeHeader.font = UIFont.systemFont(ofSize: 20)

    let ingredient1Name = UILabel(frame: CGRect(x:70,y:210,width:200,height:20))
    ingredient1Name.setActivityDescription(label: "Vanilla extract")
    ingredient1Name.font = UIFont.systemFont(ofSize: 16)

    let ingredient1Amount = UILabel(frame: CGRect(x:72,y:230,width:200,height:20))
    ingredient1Amount.setActivityDescription(label: "1 tablespoons")
    ingredient1Amount.font = UIFont.systemFont(ofSize: 12)

    let ingredient2Name = UILabel(frame: CGRect(x:70,y:260,width:200,height:20))
    ingredient2Name.setActivityDescription(label: "Sugar")
    ingredient2Name.font = UIFont.systemFont(ofSize: 16)

    let ingredient2Amount = UILabel(frame: CGRect(x:72,y:280,width:200,height:20))
    ingredient2Amount.setActivityDescription(label: "3 tablespoons")
    ingredient2Amount.font = UIFont.systemFont(ofSize: 12)

    byRecipeContainerView = UIView(frame: ...)
    byRecipeContainerView.addSubview(recipeHeader)
    byRecipeContainerView.addSubview(ingredient1Name)
    byRecipeContainerView.addSubview(ingredient1Amount)
    byRecipeContainerView.addSubview(ingredient2Name)
    byRecipeContainerView.addSubview(ingredient2Amount)
}

注意，我省略了视图的框架。请给容器视图一个足够大的框架，以容纳所有的子视图，并调整子视图的框架，使它们是 相对于容器视图的坐标系.

另外，你似乎在两种方法中都画了同样的线，所以可以做一次就再也不做了。

func drawLines() {
    view.layer.addSublayer(drawLine(x1:0, y1:310, x2:420, y2:310, lineWidth:0.5))
    view.layer.addSublayer(drawLine(x1:70, y1:255, x2:350, y2:255, lineWidth:0.3))
}

在 viewDidLoad你可以调用这三个方法。

setUpContentByDepartment()
setUpContentByRecipe()
drawLines()
view.addSubview(byDepartmentContainerView)
view.addSubview(byRecipeContainerView)
byRecipeContainerView.isHidden = true

现在你可以做一些像这样的事情了

switch sender.selectedSegmentIndex {
    case 0:
        byRecipeContainerView.isHidden = true
        byDepartmentContainerView.isHidden = false
    case 1:
        byRecipeContainerView.isHidden = false
        byDepartmentContainerView.isHidden = true
    default:
        break
}

P. S. 硬编码视图的框架是一个非常糟糕的主意。它不能本地化，不能适应不同的设备，还有其他问题。请了解一下 自动排版约束.

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