我的任务是创建一个可以更改和保存背景的应用程序。我想做些更复杂的事情，所以我决定创建一个颜色菜单，让我可以更改所有视图的背景。现在，我有了菜单，而且我知道如何在背景中设置和保存图片/颜色。但是我不知道如何从视图控制器到另一个。现在，我的代码更改了其自己的视图背景。这是我的代码（我知道很多...）：
首先，我有2个扩展名，这些扩展名使我可以：1）使用用户默认值保存UIColor； 2）使用rgb颜色：
//MARK: - Extension for rgb
extension UIColor {
convenience init(red: Int, green: Int, blue: Int) {
assert(red >= 0 && red <= 255, "Invalid red component")
assert(green >= 0 && green <= 255, "Invalid green component")
assert(blue >= 0 && blue <= 255, "Invalid blue component")
self.init(red: CGFloat(red) / 255.0, green: CGFloat(green) / 255.0, blue: CGFloat(blue) / 255.0, alpha: 1.0)
}
convenience init(rgb: Int) {
self.init(
red: (rgb >> 16) & 0xFF,
green: (rgb >> 8) & 0xFF,
blue: rgb & 0xFF
)
}
}
//MARK: - Extension to save colors
extension UserDefaults {
func setColor(color: UIColor?, forKey key: String) {
var colorData: NSData?
if let color = color {
do {
colorData = try NSKeyedArchiver.archivedData(withRootObject: color, requiringSecureCoding: false) as NSData?
set(colorData, forKey: key)
} catch let error {
print("error archiving color data", error)
}
}
}
func colorForKey(key: String) -> UIColor? {
var color: UIColor?
if let colorData = data(forKey: "Background") {
do{
color = try NSKeyedUnarchiver.unarchivedObject(ofClass: UIColor.self, from: colorData)
} catch let error {
print("error unarchivig color data", error)
}
}
return color
}
}
我的viewDidLoad：
var defaults = UserDefaults.standard
private let backgroundKey = "backg"
override func viewDidLoad() {
super.viewDidLoad()
//MARK: - Background Settings
let color = defaults.colorForKey(key: backgroundKey)
view.backgroundColor = color
if let backgroundImage = self.getSavedBackgroundImage() {
self.backgroundImageView.image = backgroundImage
}
}
允许我将图片设置为背景的代码
@IBOutlet weak var backgroundImageView: UIImageView!
//I KNOW THIS HAS TO BE PUT IN THE VC WHERE I WANT THE BACKGROUND TO BE CHANGED
@IBAction func pictureButton(_ sender: Any) {
let imagePicker = UIImagePickerController()
imagePicker.delegate = self
imagePicker.sourceType = .photoLibrary
imagePicker.allowsEditing = false
present(imagePicker, animated: true, completion: nil)
}
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
if let image = info[UIImagePickerController.InfoKey.originalImage] as? UIImage {
backgroundImageView.image = image
let _ = self.saveBackgroundImage(image: image)
}
self.dismiss(animated: true, completion: nil)
}
func saveBackgroundImage(image: UIImage) -> Bool {
guard let data = image.pngData() ?? backgroundImageView.image?.pngData() else {
return false
}
guard let directory = FileManager.default.urls(for: .documentDirectory,
in: .userDomainMask).first else {
return false
}
do {
try data.write(to: directory.appendingPathComponent("MainBackgroound.png"))
return true
} catch {
print(error.localizedDescription)
return false
}
}
func getSavedBackgroundImage() -> UIImage? {
if let dir = FileManager.default.urls(for: .documentDirectory,
in: .userDomainMask).first {
return UIImage(contentsOfFile: URL(fileURLWithPath: dir.absoluteString).appendingPathComponent("MainBackgroound.png").path)
}
return nil
}
func deleteImage() {
let fileManager = FileManager.default
let yourProjectImagesPath = (NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as NSString).appendingPathComponent("MainBackgroound.png")
if fileManager.fileExists(atPath: yourProjectImagesPath) {
try! fileManager.removeItem(atPath: yourProjectImagesPath)
}
let yourProjectDirectoryPath = (NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as NSString).appendingPathComponent("MainBackgroound.png")
if fileManager.fileExists(atPath: yourProjectDirectoryPath) {
try! fileManager.removeItem(atPath: yourProjectDirectoryPath)
}
}
允许我更改背景颜色的代码
@IBAction func lightPinkButton(_ sender: Any) {
self.deleteImage()
let lightPink = UIColor(red: 255, green: 215, blue: 214).withAlphaComponent(1)
defaults.setColor(color: lightPink, forKey: backgroundKey)
view.backgroundColor = lightPink
}
答案 0 :(得分：1)
如何创建诸如ColorViewController之类的基本视图控制器，在其中您可以引用背景色，然后从中继承并在需要时进行更新。
赞
class ColorViewController: UIViewController {
var myBackgroundColor: UIColor = .white
override func viewDidLoad() {
super.viewDidLoad()
}
}
class ViewControllerOne: ColorViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
view.backgroundColor = myBackgroundColor
}
@IBAction func blueButtonTapped(_ sender: Any) {
myBackgroundColor = .blue
view.backgroundColor = myBackgroundColor
}
}
class ViewControllerTwo: ColorViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
view.backgroundColor = myBackgroundColor
}
@IBAction func purpleButton(_ sender: Any) {
myBackgroundColor = .purple
view.backgroundColor = myBackgroundColor
}
}
答案 1 :(得分：0)
对于背景颜色何时更改以及背景图像何时更改，您应该使用Notification。任何以主题为主题的ViewController都需要侦听这些通知并相应地进行更新：
//Make your custom notification
extension Notification.Name {
static let backgroundColorUpdated = Notification.Name("backgroundColorUpdated")
}
//Post the notification when you update backgroundColor
NotificationCenter.default.post(Notification(name: .backgroundColorUpdated, object: nil, userInfo: ["backgroundColor": UIColor.red]))
//Subscribe everywhere that needs to be interested in backgroundColor changes
var token: NSObjectProtocol? // retain token for life of subscription, ie as long as you vc exists
...
token = NotificationCenter.default.addObserver(forName: .backgroundColorUpdated, object: nil, queue: .main) { notification in
guard let backgroundColor = notification.userInfo?["backgroundColor"] as? UIColor else {
return
}
//Do stuff with backgroundColors here
}