Can you change the background image each time you click the button? - ios

Question

I've checked the documentation and have successfully added an image as a background, however, I can't change it now that it's been set.
What I want to do is to change the background Image each time I click the button. Looking online I've found information on how to change the buttons background, but not the actual background.
import UIKit
class ViewController: UIViewController {
var arrays = ["A", "b", "C", "D", "E", "F"]
var currentIndex = 0
var image = UIImage()
var image3 = UIImage()
#IBOutlet weak var ChangeText: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
ChangeText.text = arrays[currentIndex]
self.view.backgroundColor = UIColor(patternImage: UIImage(named: "LaunchImage")!)
self.view.backgroundColor = UIColor(patternImage: UIImage(named: "Image2")!)
}
#IBAction func Button() {
currentIndex += 1
if currentIndex == arrays.count {
currentIndex = 0
}
ChangeText.text = arrays[currentIndex]
if image == UIImage(named: "Image2") {
print("Image")
}
self.view.backgroundColor = UIColor(patternImage: UIImage(named: "Image2")!)
}
}
Also is it OK to force unwrap UIImage I know force unwrapping is frowned upon however I know for sure that I will have a background image.
I tried this as well but Im having the same problem it wont change the background image more than once.
```
#IBAction func Button() {
currentIndex += 1
if currentIndex == arrays.count {
currentIndex = 0
}
ChangeText.text = arrays[currentIndex]
if image == UIImage(named: "Image2") {
print("Image")
}
self.view.backgroundColor = UIColor(patternImage: UIImage(named: "Image2")!)
if image3 == UIImage(named: "Image3") {
print("Image")
}
self.view.backgroundColor = UIColor(patternImage: UIImage(named: "Image3")!)
}
}
```

Answer 1

I'm not sure where the problem is, as you haven't shown us what you have already tried.
The same code that you have used to set the background view can be used anywhere, and as often as you like
if <some condition>
{
self.view.backgroundColor = UIColor(patternImage: UIImage(named: "one")!)
}
if <another condition>
{
self.view.backgroundColor = UIColor(patternImage: UIImage(named: "two")!)
}

Answer 2

I don't think your question is related to the buttons so much as general concepts, like conditions. As Russel answered, you simply need conditions. You've already demonstrated image loading is doable, so now you just need to do it "again" with a different image.
I have a few tips. First, don't name functions with nouns, say ButtonTapped or similar. Button, in swift 3, will be/is a UIButton, so it won't work as you expect anyway.
I realize you were not changing the Button's background, but I thought you were. If you were, Buttons don't behave like images and views. They have "Background for state" and "title for state". Heck, you can't even scale them using Core Animation, you have to scale their superview to see it. Although I'd hold off on Core Animation for now.
What you want to do is what Russel said, but try something simple. Like:
var switch:bool = true;
func buttonTapped() {
if (switch == true) {
self.view.backgroundColor = UIColor(patternImage: UIImage(named: "one");
} else {
self.view.backgroundColor = UIColor(patternImage: UIImage(named: "two");
}
switch = !switch;
}
I would first do something easy though to prove it's working
self.view.backgroundColor = UIColor.blackColor(); and orange/white anything.
Whether you should force unwrap things or not, gaining good naming habits, understanding structure, etc... I would recommend learning C++. A simple C++ tutorial will cover more structure and modularization than any beginner book on swift or iPhone programming. Plus, every other language is just a fraction of its features, so you'll pick everything else up super quick.

Answer 3

Replace your code with this:
#IBAction func Button() {
currentIndex += 1
if currentIndex == arrays.count {
currentIndex = 0
}
ChangeText.text = arrays[currentIndex]
if image == UIImage(named: "Image2")
{
self.view.backgroundColor = UIColor(patternImage: UIImage(named: "Image3")!)
return;
}
else if image3 == UIImage(named: "Image3")
{
self.view.backgroundColor = UIColor(patternImage: UIImage(named: "Image4")!)
return;
}
else if image == UIImage(named: "Image")
{
self.view.backgroundColor = UIColor(patternImage: UIImage(named: "Image2")!)
return;
}
else
{
self.view.backgroundColor = UIColor(patternImage: UIImage(named: "Image")!)
return;
}
}