刷新 UIImageView 的图片

Question

I have a question that has probably been asked a lot, but I just can't get it. I'm making an iOS tabbed app with Swift 5 and Xcode 11. I have a background UIImageView that changes the image every time a user presses a button. The image actually displays pretty well, there's just one thing: The background image doesn't change, it just takes the previous image. Here's my code:

    func theme(){
        let backgroundImage = UIImageView(frame: self.view1.bounds)
        backgroundImage.autoresizingMask = [.flexibleHeight, .flexibleWidth]
        self.view1.insertSubview(backgroundImage, at: 0)
        if UserDefaults.standard.integer(forKey: "like") == 1{
            backgroundImage.image = nil
            backgroundImage.image = UIImage(named: "img1")
            self.tabBarController?.tabBar.barTintColor = UIColor(red:0.84, green:0.84, blue:0.84, alpha:1.0)
            self.tabBarController?.tabBar.tintColor = UIColor(red:0.21, green:0.56, blue:0.96, alpha:1.0)
            ansView.backgroundColor = UIColor.white
            historyButton.backgroundColor = UIColor.black
            for button in operatorButtons {
                button.backgroundColor = UIColor.black
            }
            for button in numberButtons {
                button.backgroundColor = UIColor(red:0.53, green:0.52, blue:0.53, alpha:0.5)
            }
            equalButton.backgroundColor = UIColor(red:1.00, green:0.49, blue:0.18, alpha:1.0)
            self.view.backgroundColor = UIColor(red:0.78, green:0.78, blue:0.78, alpha:1.0)
            view1.contentMode = UIView.ContentMode.scaleAspectFill
        }else if UserDefaults.standard.integer(forKey: "like") == 2{
            self.tabBarController?.tabBar.barTintColor = UIColor.black
            self.tabBarController?.tabBar.tintColor = UIColor(red:0.98, green:0.64, blue:0.02, alpha:1.0)
            backgroundImage.image = nil
            backgroundImage.image = UIImage(named: "img2")
            ansView.backgroundColor = UIColor(red:0.53, green:0.52, blue:0.53, alpha:1)
            historyButton.backgroundColor = UIColor(red:0.00, green:0.00, blue:0.00, alpha:0.9)
            for button in operatorButtons {
                button.backgroundColor = UIColor(red:0.00, green:0.00, blue:0.00, alpha:0.9)
            }
            for button in numberButtons {
                button.backgroundColor = UIColor(red:0.53, green:0.52, blue:0.53, alpha:0.5)
            }
            equalButton.backgroundColor = UIColor(red:0.53, green:0.52, blue:0.53, alpha:0.5)
            self.view.backgroundColor = UIColor.black
            view1.contentMode = UIView.ContentMode.scaleAspectFill
        }else if UserDefaults.standard.integer(forKey: "like") == 3{
            self.tabBarController?.tabBar.barTintColor = UIColor(red:0.78, green:0.75, blue:0.90, alpha:1.0)
            self.tabBarController?.tabBar.tintColor = UIColor(red:0.51, green:0.44, blue:0.78, alpha:1.0)
            view1.backgroundColor = UIColor(patternImage: UIImage(named: "ing3")!)
            ansView.backgroundColor = UIColor(red:1.00, green:1.00, blue:1.00, alpha:0.5)
            historyButton.backgroundColor = UIColor(red:0.60, green:0.54, blue:0.82, alpha:1.0)
            for button in operatorButtons {
                button.backgroundColor = UIColor(red:0.60, green:0.54, blue:0.82, alpha:1.0)
            }
            for button in numberButtons {
                button.backgroundColor = UIColor(red:1.00, green:1.00, blue:1.00, alpha:0.5)
            }
            equalButton.backgroundColor = UIColor(red:0.51, green:0.44, blue:0.78, alpha:1.0)
            self.view.backgroundColor = UIColor(red:0.78, green:0.75, blue:0.90, alpha:1.0)
            view1.contentMode = UIView.ContentMode.scaleToFill
        }
    }

The above code was my theme function, which I call every time the view appears. As you see above, I have tried

backgroundImage.image = nil

But it didn't work for me. I have also searched stack-overflow for similar questions, but it was no use. Any help is appreciated

Answer 1

In the third condition you forgot to set image or it's intentionally ? And there is no need to set nil before replacing the new image.