3.iOS14下UIPageControl自定義樣式

3.iOS14下UIPageControl自定義樣式

1.概覽

首先在iOS14中UIPageControl中增長了幾個新屬性及方法：

/// 表示當前的背景樣式，枚舉值
open var backgroundStyle: UIPageControl.BackgroundStyle
/// 只讀屬性，表示當前處於離散互動仍是連續互動
open var interactionState: UIPageControl.InteractionState { get }
/// 表示是否開始連續互動，默認true
open var allowsContinuousInteraction: Bool
/// 指示器樣式統一調整，默認nil，樣式爲圓點
open var preferredIndicatorImage: UIImage?
/// 獲取page處對應的圖片，沒有設置則爲nil
open func indicatorImage(forPage page: Int) -> UIImage?
/// 設置page處對應的圖片
open func setIndicatorImage(_ image: UIImage?, forPage page: Int)

同時廢棄了一個方法和屬性：

/// 設置該屬性後，延緩更新指示器，直到調用updateCurrentPageDisplay爲止
open var defersCurrentPageDisplay: Bool
/// 更新指示器
open func updateCurrentPageDisplay()

2.部分新增屬性及方法

2.1 preferredIndicatorImage

let control = UIPageControl()
control.numberOfPages = 10
control.frame = CGRect(x: 0, y: 300, width: 350, height: 30)
control.pageIndicatorTintColor = .systemRed
control.currentPageIndicatorTintColor = .systemGreen
if #available(iOS 14.0, *) {
    control.preferredIndicatorImage = UIImage(named:"heart")
}
self.view.addSubview(control)

preferredIndicatorImage能夠將指示器圖片替換成任意咱們想要的圖片

2.2 setIndicatorImage(UIImage?, forPage: Int)

能夠設置任意page對應的圖片，若是image爲nil的話則顯示圓點

let indicatorImages = ["summy", "cloudy", "rainy", "thunder"]
if #available(iOS 14.0, *) {
    for (idx, imageName) in indicatorImages.enumerated() {
        control.setIndicatorImage(UIImage(named:imageName), forPage: idx)
    }
}

2.3 自定義樣式

經過iOS14中新增的幾個屬性，只能實現簡單的自定義樣式，想要實現徹底的自定義仍舊須要採用以前的辦法，在這以前先看一下UIPageControl在iOS14中層級的變化

[iOS 13] [iOS 14]

圓點有原先UIView一個視圖變成了由_UIPageControlContentView、_UIPageControlIndicatorContentView、_UIPageIndicatorView組合的視圖，因爲_UIPageIndicatorView是一個UIImageView，因此咱們能夠直接使用這個視圖來呈現

if #available(iOS 14.0, *) {
    guard let dotContentView = findIndicatorContentView() else {
        return
    }
    
    for (index, view) in dotContentView.subviews.enumerated() {
        if view.isKind(of: UIImageView.self) {
            self.currentPageIndicatorTintColor = self.currentTintColor
            self.pageIndicatorTintColor = self.inactiveTintColor
            
            let indicatorView = view as! UIImageView
            indicatorView.image = nil
            if index == self.currentPage {
                indicatorView.image = currentImage.withRenderingMode(.alwaysTemplate)
            } else {
                indicatorView.image = inactiveImage.withRenderingMode(.alwaysTemplate)
            }
        }
    }
}

@available(iOS 14.0, *)
func findIndicatorContentView() -> UIView? {
    for contentView in self.subviews {
        if let contentViewClass = NSClassFromString("_UIPageControlContentView"), contentView.isKind(of: contentViewClass) {
            for indicatorContentView in contentView.subviews {
                if let indicatorContentViewClass = NSClassFromString("_UIPageControlIndicatorContentView"), indicatorContentView.isKind(of: indicatorContentViewClass) {
                    return indicatorContentView
                }
            }
        }
    }
    return nil
}

[自定義pageControl]

3.代碼地址

小小個子大個頭