记录用户上次图片操作位置和缩放比, 下次进来直接展示上次退出的位置
需求: 图片可以缩放,可滚动. 并且第二次进来的时候. 直接展示上次退出界面时候的图片大小和位置
解决思路: uiscrollView + 偏好缓存(或者fmdb, 缓存方式自己选择).
直接上代码
import UIKit
class test2: UIViewController, UIScrollViewDelegate {
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
print(UIApplication.shared.windows.count)
}
private lazy var scrollV: UIScrollView = {
let v = UIScrollView(frame: CGRect(x: 100, y: 100, width: 300, height: 300))
v.maximumZoomScale = 3
v.minimumZoomScale = 1
v.backgroundColor = .red
v.delegate = self
return v
}()
private lazy var imageV: UIImageView = {
let v = UIImageView(frame: CGRect(x: 100, y: 100, width: 300, height: 300))
v.image = imageLiteral(resourceName: "1242-2208.png")
return v
}()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .yellow
view.addSubview(scrollV)
scrollV.addSubview(imageV)
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
scrollV.zoomScale = CGFloat(UserDefaults.standard.float(forKey: "currentZoom") )
let x = CGFloat( UserDefaults.standard.float(forKey: "x"))
let y = CGFloat( UserDefaults.standard.float(forKey: "y"))
scrollV.contentOffset = CGPoint(x: x, y: y)
}
func viewForZooming(in scrollView: UIScrollView) -> UIView? {
return imageV
}
private var currentZoom: CGFloat = 1
func scrollViewDidEndZooming(_ scrollView: UIScrollView, with view: UIView?, atScale scale: CGFloat) {
currentZoom = scale
UserDefaults.standard.setValue(currentZoom, forKey: "currentZoom")
print(scrollView.contentOffset)
UserDefaults.standard.setValue(scrollView.contentOffset.x, forKey: "x")
UserDefaults.standard.setValue(scrollView.contentOffset.y, forKey: "y")
}
}