即使我退出 view \ App ,我也试图通过保存它的状态来完成我最喜欢的按钮。如果有人能告诉我我该怎么做,那就太好了
我正在使用 Xcode 8 并使用 Swift 3 进行编码。
//create a new button
let Favoritebutton: UIButton = UIButton(type: UIButtonType.custom)
//set image for button
Favoritebutton.setImage(UIImage(named: "EmptyHeart.png"), for: .normal)
Favoritebutton.setImage(UIImage(named: "FilledHeart.png"), for: .selected)
//add function for button
Favoritebutton.addTarget(self, action: #selector(self.button), for: .touchUpInside)
//set frame
Favoritebutton.frame = CGRect(x:0,y: 0,width: 35,height: 35)
Favoritebutton.isSelected = UserDefaults.standard.bool(forKey: "isSaved")
let barButton = UIBarButtonItem(customView: Favoritebutton)
//assign button to navigationbar
self.navigationItem.rightBarButtonItem = barButton
let state = UserDefaults.standard.bool(forKey: "isSaved") ?? false
}
@IBAction func button(sender: UIButton) {
sender.isSelected = !sender.isSelected
if let Favoritebutton = sender as? UIButton {
Favoritebutton.isSelected = UserDefaults.standard.bool(forKey: "isSaved")
if Favoritebutton.isSelected {
// set selected
Favoritebutton.isSelected = true
// set badge Value to tabbar item.
let tabItem = self.tabBarController?.tabBar.items![3]
sel_val = tabItem?.badgeValue
if(sel_val == nil){
sel_val = "0"
}
let sel_num = Int(sel_val!)
tabItem!.badgeValue = String(format: "%d", sel_num! + 1) as String
//Add Favorite
let Fav: NSMutableArray = []
Fav.add(barImage)
Fav.add(barName)
Fav.add(streetName)
favorite.add(Fav)
} else {
// set deselected
Favoritebutton.isSelected = false
//Badge Value Count.
let tabItem = self.tabBarController?.tabBar.items![3]
sel_val = tabItem?.badgeValue
if(sel_val == nil){
sel_val = "0"
}
let sel_num = Int(sel_val!)
tabItem!.badgeValue = String(format: "%d", sel_num! - 1) as String
//Remove Favorite
let Fav: NSMutableArray = []
Fav.add(barImage)
Fav.add(barName)
Fav.add(streetName)
favorite.remove(Fav)
}
}
您可以减少代码button
to
@IBAction func button(sender: UIButton) {
sender.isSelected = !sender.isSelected
UserDefaults.standard.set(sender.isSelected, forKey: "isSaved")
}
要设置状态,您必须将其读回
let Favoritebutton = UIButton(type: UIButtonType.custom)
//set image for button
Favoritebutton.setImage(UIImage(named: "EmptyHeart.png"), for: .normal)
Favoritebutton.setImage(UIImage(named: "FilledHeart.png"), for: .selected)
Favoritebutton.isSelected = UserDefaults.standard.bool(forKey: "isSaved")
...
Edit:
我不知道你的代码是做什么的,但有很多冗余代码。这IBAction
可以简化为(当然未经测试)
@IBAction func button(sender: UIButton) {
let newValue = !sender.isSelected
sender.isSelected = newValue
UserDefaults.standard.set(newValue, forKey: "isSaved")
let tabItem = self.tabBarController?.tabBar.items![3]
sel_val = tabItem?.badgeValue
if(sel_val == nil){
sel_val = "0"
}
let sel_num = Int(sel_val!)
let fav: NSMutableArray = []
fav.add(barImage)
fav.add(barName)
fav.add(streetName)
if sender.isSelected {
tabItem!.badgeValue = String(format: "%d", sel_num! + 1)
favorite.add(fav)
} else {
tabItem!.badgeValue = String(format: "%d", sel_num! - 1)
favorite.remove(fav)
}
}
并请以小写字母开头命名变量。
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