I have set up my UIImageView using the below setup. I am trying to draw on the view but can not get anything to appear. I am new to Xcode and want my view to automatically change depending on what the screen size is. When I have used the storyboard I could not figure out how to get the view to change with the screen size and/or rotation. As a result I figured it would be easier to make that happen in the ViewController.swift file. When the program wasn't working I tried to see if the view was appearing on the screen. When I made one of the views red, I still could not see anything on the screen. I am very confused. I am open to any feedback. I appreciate you taking time to read this and am looking forward to assistance.
Thanks,
T
import UIKit
import CoreGraphics
class ViewController: UIViewController {
var ResultImageView = UIImageView ( frame: UIScreen.mainScreen().bounds)
var DrawingImageView = UIImageView ( frame: UIScreen.mainScreen().bounds)
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
ResultImageView.userInteractionEnabled = true
ResultImageView.backgroundColor = UIColor.redColor()
DrawingImageView.userInteractionEnabled = true
}
I think the problem is you have to create the imageview in viewDidAppear if you're setting the screen size, because the screen size hasn't been set and orientated where you're setting it. Try the below and hope this issue gets resolved soon :)
var ResultImageView = UIImageView()
var DrawingImageView = UIImageView()
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(true)
ResultImageView = UIImageView (frame: self.view.frame)
DrawingImageView = UIImageView (frame: self.view.frame)
ResultImageView.userInteractionEnabled = true
self.view.addSubview(ResultImageView)
self.view.addSubview(DrawingImageView)
ResultImageView.backgroundColor = UIColor.redColor()
DrawingImageView.userInteractionEnabled = true
}
Related
I have been following this tutorial. I downloaded the source and tried "translating" it to Swift. This is my "translated" code:
import Cocoa
import AppKit
import MetalKit
import simd
class MetalViewController: NSViewController {
#IBOutlet var inview: MTKView!
override func viewDidLoad() {
super.viewDidLoad()
let _view: MTKView = self.inview
_view.device = MTLCreateSystemDefaultDevice()
let _renderer: Renderer=initView(view: _view)
_view.delegate=_renderer as? MTKViewDelegate
_view.preferredFramesPerSecond=60
}
}
class Renderer: NSObject {
init(device: MTLDevice){
self._device=device
self._commandQueue=_device.makeCommandQueue()!
super.init()
}
func mtkView(_ view: MTKView, drawableSizeWillChange size: CGSize) {
}
func draw(in view: MTKView) {
let color = Color(red: 1.0,green: 0.0,blue: 0.0,alpha: 0.0)
view.clearColor = MTLClearColorMake(color.red, color.green, color.blue, color.alpha)
let commandbuffer = _commandQueue.makeCommandBuffer()
let renderpassdescriptor: MTLRenderPassDescriptor = view.currentRenderPassDescriptor!
let renderencoder: MTLRenderCommandEncoder = (commandbuffer?.makeRenderCommandEncoder(descriptor: renderpassdescriptor))!
renderencoder.endEncoding()
commandbuffer!.present(view.currentDrawable!)
commandbuffer!.commit()
}
var _device: MTLDevice
var _commandQueue: MTLCommandQueue
}
struct Color{
var red, green, blue, alpha: Double
}
func initView(view: MTKView) -> Renderer{
var renderer: Renderer
renderer=Renderer(device: view.device!)
return renderer
}
So I put the AAPLRenderer and AAPLViewControllers into one file, and made it so that there are no header files. I linked the view with #IBOutlet to the view controller because the view was a NSView and I cannot cast it to MTKView without getting a compile time error. The AppDelegate is the original one and I do not have a main file.
I end up with a window that does not show red, but rather shows nothing. I do not understand why this is happening. Please help me, thank you.
I see two issues.
1) MTKView's delegate property is a weak var, which means that if you don't hold onto an instance of your renderer, it'll be immediately deinited and never receive any delegate callbacks. Keep a reference to your renderer as a property on your view controller.
class MetalViewController: NSViewController {
#IBOutlet var inview: MTKView!
var renderer: Renderer!
override func viewDidLoad() {
// ...
let view: MTKView = self.inview
// ...
renderer = initView(view: view)
view.delegate = renderer
// ...
}
}
2) Because the Renderer class doesn't explicitly declare conformance to the MTKViewDelegate protocol, the conditional cast when assigning it as the view's delegate fails. Make Renderer explicitly conform to the protocol, and remove the conditional cast as shown above.
class Renderer: NSObject, MTKViewDelegate
Well, it could be anything. But, the first thing I would check is that your alpha setting for that red color should have alpha = 1.0 and not alpha = 0.0.
In Apple's official Exhibition app demo, there's such usage in viewDidLoad() in the ImageViewerController.swift
/*
Turn on translatesAutoresizingMaskIntoConstraints, Interface Builder
turns this off for all views in a nib. The `NSScrollView` and `NSClipView`
expect to be able to control their documentView via modifying its `frame`.
*/
imageView.translatesAutoresizingMaskIntoConstraints = true
I noticed that in the xib file, the imageView already has constrains set up. When the line of code is commented out, the view still works.
To better understand the code from the demo, I created a minimal project with only a NSScrollView added under the default view controller's view. Here the NSImageView is created programmatically. If the constrains in h and v are activated, the window will be very big and unresponsive to resizing and dragging.
class ViewController: NSViewController {
#IBOutlet weak var scrollView: NSScrollView!
#IBOutlet weak var clipView: NSClipView!
override func viewDidLoad() {
super.viewDidLoad()
let path = "/Library/Desktop Pictures/Snow.jpg"
let url = URL(fileURLWithPath: path, isDirectory: false)
let image = NSImage(contentsOf: url)
let imageView = NSImageView(image: image!)
imageView.translatesAutoresizingMaskIntoConstraints = false
clipView.addSubview(imageView)
let h = NSLayoutConstraint.constraints(
withVisualFormat: "H:|[imageView]|",
options: NSLayoutConstraint.FormatOptions(rawValue: 0),
metrics: nil,
views: ["imageView" : imageView])
let v = NSLayoutConstraint.constraints(
withVisualFormat: "V:|[imageView]|",
options: NSLayoutConstraint.FormatOptions(rawValue: 0),
metrics: nil,
views: ["imageView" : imageView])
clipView.documentView = imageView
// NSLayoutConstraint.activate([h, v].flatMap({$0}))
}
}
My questions are:
Why and how do the constrains in my project cause the problem, while the constrains in the demo don't.
Are the constrains in the official demo necessary?
At first glance they look like regular UIButtons however they got a label below it. Also the background of the button seems to be a blurred effect.
So my thoughts are that they are put in a CollectionView (Horizontal). With each cell containing a UIButton and a UILabel. Although that may work the UIButton doesn't seem to get the move effect for free.
Is that custom behavior? And if so, how are you able to create such an effect?
I bet it is not an UICollectionView but a horizontal UIStackView of custom views in which there is a UIButton and UILabel vertically aligned.
Here you have an example, using stackViews:
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let stackView = UIStackView()
stackView.axis = .horizontal
stackView.distribution = .equalSpacing
stackView.alignment = .center
stackView.spacing = 30
view.addSubview(stackView)
["One", "Two", "Three", "Caramba"].forEach {
let buttonStackView = UIStackView()
buttonStackView.axis = .vertical
buttonStackView.distribution = .fillProportionally
buttonStackView.alignment = .center
buttonStackView.spacing = 15
let button = UIButton(type: .system)
button.setTitle($0, for: .normal)
buttonStackView.addArrangedSubview(button)
let label = UILabel()
label.text = $0
label.font = UIFont.systemFont(ofSize: 20)
buttonStackView.addArrangedSubview(label)
stackView.addArrangedSubview(buttonStackView)
}
stackView.translatesAutoresizingMaskIntoConstraints = false
stackView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
stackView.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
}
}
Having a custom view instead of a vertical uistackview for each button would allow to customize its layout when focused, including Parallax effect.
For adding parallax effect to each button in the stack, take a look to How to get Parallax Effect on UIButton in tvOS?
So i have created a couple of different SKScenes in my swift project and I've seen on a couple tutorials that you don't have to launch you gameScene.swift as your first scene, however i can not find a tutorial that explains how
import UIKit
import SpriteKit
class GameViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
if let scene = GameScene(fileNamed:"GameScene") {
// Configure the view.
let skView = self.view as! SKView
skView.showsFPS = true
skView.showsNodeCount = true
/* Sprite Kit applies additional optimizations to improve
rendering performance */
skView.ignoresSiblingOrder = true
/* Set the scale mode to scale to fit the window */
scene.scaleMode = .AspectFill
skView.presentScene(scene)
}
}
}
Im trying to change the GameScene SKS to my MainMenu SKS, but i keep getting errors and I'm definitely missing something. Can anyone help me out?
import UIKit
import SpriteKit
class GameViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
if let newScene = MenuScene(fileNamed:"MenuScene") {
// Configure the view.
let skView = self.view as! SKView
skView.showsFPS = true
skView.showsNodeCount = true
/* Sprite Kit applies additional optimizations to improve
rendering performance */
skView.ignoresSiblingOrder = true
/* Set the scale mode to scale to fit the window */
newScene.scaleMode = .AspectFill
skView.presentScene(newScene)
}
}
}
So instead of having GameScene as your initial scene, just create MenuScene instance and present it in your viewDidLoad. Note that you have to create coresponding MenuScene.sks file because of this line:
If let newScene = MenuScene(fileNamed:"MenuScene.sks"){
//...}
because you are loading it from a file.
Also to transition to another scene, use following pattern and for example in touchesBegan create new scene, optionally create SKTransition and present the new scene.
Just call that code whenever you want. For example, you can connect it with a button.
#IBAction func playGame(sender: AnyObject) {
if let scene = GameScene(fileNamed:"GameScene") {
...
}
}
this is what I used in a Sprite Kit project. It was I while ago and I dont remember any of the reasoning behind it.
if let scene = DesiredScene.unarchiveFromFile("DesiredScene") as? DesiredScene
perhaps someone else can elucidate whats going on
I am looking for an effective way to re-position a popover using the new uipopoverpresentationcontroller. I have succesfully presented the popover, and now I want to move it without dismissing and presenting again. I am having trouble using the function:
(void)popoverPresentationController:(UIPopoverPresentationController *)popoverPresentationController
willRepositionPopoverToRect:(inout CGRect *)rect
inView:(inout UIView **)view
I know it's early in the game, but it anyone has an example of how to do this efficiently I would be grateful if you shared it with me. Thanks in advance.
Unfortunately this hacky workaround is the only solution I've found:
[vc.popoverPresentationController setSourceRect:newSourceRect];
[vc setPreferredContentSize:CGRectInset(vc.view.frame, -0.01, 0.0).size];
This temporarily changes the content size of the presented view, causing the popover and arrow to be repositioned. The temporary change in size is not visible.
It seems this is a problem Apple need to fix - changing the sourceView or sourceRect properties of UIPopoverPresentationController does nothing when it's already presenting a popover (without this workaround).
Hope this works for you too!
I had luck using containerView?.setNeedsLayout() and containerView?.layoutIfNeeded() after changing the sourceRect of the popoverPresentationController, like so:
func movePopoverTo(_ newRect: CGRect) {
let popover = self.presentedViewController as? MyPopoverViewController {
popover.popoverPresentationController?.sourceRect = newRect
popover.popoverPresentationController?.containerView?.setNeedsLayout()
popover.popoverPresentationController?.containerView?.layoutIfNeeded()
}
}
And even to have a popover follow a tableView cell without having to change anything:
class MyTableViewController: UITableViewController {
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "MyPopoverSegue" {
guard let controller = segue.destination as? MyPopoverViewController else { fatalError("Expected destination controller to be a 'MyPopoverViewController'!") }
guard let popoverPresentationController = controller.popoverPresentationController else { fatalError("No popoverPresentationController!") }
guard let rowIndexPath = sender as? IndexPath else { fatalError("Expected sender to be an 'IndexPath'!") }
guard myData.count > rowIndexPath.row else { fatalError("Index (\(rowIndexPath.row)) Out Of Bounds for array (count: \(myData.count))!") }
if self.presentedViewController is MyPopoverViewController {
self.presentedViewController?.dismiss(animated: false)
}
popoverPresentationController.sourceView = self.tableView
popoverPresentationController.sourceRect = self.tableView.rectForRow(at: rowIndexPath)
popoverPresentationController.passthroughViews = [self.tableView]
controller.configure(myData[rowIndexPath.row])
}
super.prepare(for: segue, sender: sender)
}
}
// MARK: - UIScrollViewDelegate
extension MyTableViewController {
override func scrollViewDidScroll(_ scrollView: UIScrollView) {
if let popover = self.presentedViewController as? MyPopoverViewController {
popover.popoverPresentationController?.containerView?.setNeedsLayout()
popover.popoverPresentationController?.containerView?.layoutIfNeeded()
}
}
}
I used the same method as mentioned in another answer by #Rowan_Jones, however I didn't want the popover's size to actually change. Even by fractions of a point. I realized that you can set the preferredContentSize multiple times back to back, but visually it's size will only change to match the last value.
[vc.popoverPresentationController setSourceRect:newSourceRect];
CGSize finalDesiredSize = CGSizeMake(320, 480);
CGSize tempSize = CGSizeMake(finalDesiredSize.width, finalDesiredSize.height + 1);
[vc setPreferredContentSize:tempSize];
[vc setPreferredContentSize:finalDesiredSize];
So even if finalDesiredSize is the same as your initial preferredContentSize this will cause the popover to be updated, even though it's size doesn't actually change.
Here is an example for how to recenter the popover:
- (void)popoverPresentationController:(UIPopoverPresentationController *)popoverPresentationController willRepositionPopoverToRect:(inout CGRect *)rect inView:(inout UIView **)view {
*rect = CGRectMake((CGRectGetWidth((*view).bounds)-2)*0.5f,(CGRectGetHeight((*view).bounds)-2)*0.5f, 2, 2);
I have also used this method to ensure that the popover moved to the correct location after moving by setting the *rect and the *view to the original sourceRect and sourceView.
As an additional note, I don't believe that this method is called when the popover's source is set using a bar button item.
I'm posting this because I don't have enough points to vote or comment. :)
#turbs's answer worked for me perfectly. It should be the accepted answer.
Setting *rect to the rect you need in the delegate method:
(void)popoverPresentationController:(UIPopoverPresentationController *)popoverPresentationController
willRepositionPopoverToRect:(inout CGRect *)rect
inView:(inout UIView **)view
iOS 12.3
[vc.popoverPresentationController setSourceRect:newSourceRect];
[vc.popoverPresentationController.containerView setNeedsLayout];