I want a picture to move to the bottom. If I press a button the pic should move down by 1.
I added the picture and a button:
var corX = 0
var corY = 0
var runter: UIButton = UIButton.buttonWithType(UIButtonType.System) as UIButton
var image = UIImage(named: "panzerBlau.jpg");
var panzer = UIImageView(frame: CGRectMake(corX, corY, 30, 40)); //
override func viewDidLoad() {
super.viewDidLoad()
panzer.image = image; //
self.view.addSubview(panzer); //
runter.frame = CGRectMake(100, 30, 10 , 10)
runter.backgroundColor = UIColor.redColor()
view.addSubview(runter)
runter.addTarget(self, action: "fahren", forControlEvents:UIControlEvents.TouchUpInside)
}
At least I said in function "fahren" to move the picture down by 1.
func fahren(){
corY += 1
panzer.frame = CGRectMake(corX, corY, 30, 40) //
self.view.addSubview(panzer);
}
So my problem is: I get several errors with these corX and corY thing. Without them it works perfectly but than its like a single-use button. The errors are: ViewController.Type does not have a member named corX and ViewController.Type does not have a member names panzer Where I get the errors I made // to show in which lines.
PS: I use Xcode Beta5
Here's the complete code without anything else:
import UIKit
class ViewController: UIViewController {
var corX = 0
var corY = 0
var runter: UIButton = UIButton.buttonWithType(UIButtonType.System) as UIButton
var image = UIImage(named: "panzerBlau.jpg");
var panzer = UIImageView(frame: CGRectMake(corX, corY, 30, 40));
override func viewDidLoad() {
super.viewDidLoad()
panzer.image = image;
self.view.addSubview(panzer);
runter.frame = CGRectMake(100, 30, 10 , 10)
runter.backgroundColor = UIColor.redColor()
view.addSubview(runter)
runter.addTarget(self, action: "fahren", forControlEvents:UIControlEvents.TouchUpInside)
}
func fahren(){
corY += 100
panzer.frame = CGRectMake(corX, corY, 30, 40)
self.view.addSubview(panzer);
}
}
@MartinR has pointed out the major issue here:
var corX = 0
var corY = 0
var panzer = UIImageView(frame: CGRectMake(corX, corY, 30, 40))
The problem is that a Swift default initializer cannot refer to the value of another property, because at the time of initialization, the property doesn't exist yet (because the instance itself doesn't exist yet). Basically, in panzer
's default initializer you are implicitly referring to self.corX
and self.corY
- but there is no self
because self
is exactly what we are in the middle of creating.
One workaround is to make the initializer lazy:
class ViewController: UIViewController {
var corX : CGFloat = 0
var corY : CGFloat = 0
lazy var panzer : UIImageView = UIImageView(frame: CGRectMake(self.corX, self.corY, 30, 40))
// ...
}
That's legal because panzer
doesn't get initialized until later, when it is first referred to by your actual code. By that time, self
and its properties exist.