drag and drop uiimage into another uiimageview - objective-c

Question

I am using following code snippet to drag and drop uiimageview
UIPanGestureRecognizer *panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(move:)];
[panRecognizer setMinimumNumberOfTouches:1];
[panRecognizer setMaximumNumberOfTouches:1];
[panRecognizer setDelegate:self];
[myImageView addGestureRecognizer:panRecognizer];
-(void)move:(id)sender {
CGPoint translatedPoint = [(UIPanGestureRecognizer*)sender translationInView:self.view];
if([(UIPanGestureRecognizer*)sender state] == UIGestureRecognizerStateBegan) {
firstX = [myImageView center].x;
firstY = [myImageView center].y;
}
translatedPoint = CGPointMake(firstX+translatedPoint.x, firstY+translatedPoint.y);
[myImageView setCenter:translatedPoint];
}
This code is drags the whole myImageView ,but my requirement is to just drag the uiimage and drop it into another uiimagview.myImageView should stay as it is after dragging also.just I need to drag the myImageView layer.draggable image should be transparent. Any ideas would b appreciated.

Answer 1

I have put little effort to achieve your output. try it
Step 1 :Define this 3 Variables in your .h file
UIImageView *ivSource1, *ivDestination2, *tempIV;
Step 2 : Initialize all the three UIImageView and add to your ViewController write it in viewDidLoad method
ivSource1 = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"1.jpg"]];
[ivSource1 setFrame:CGRectMake(100, 100, 100, 100)];
[ivSource1 setTag:100];
[ivSource1 setUserInteractionEnabled:YES];
[self.view addSubview:ivSource1];
ivDestination2 = [[UIImageView alloc] init];
[ivDestination2 setFrame:CGRectMake(200, 300, 100, 100)];
[ivDestination2 setTag:101];
[ivDestination2 setUserInteractionEnabled:YES];
[self.view addSubview:ivDestination2];
tempIV = [[UIImageView alloc] init];
[tempIV setFrame:CGRectMake(0, 300, 100, 100)];
[tempIV setTag:102];
[tempIV setUserInteractionEnabled:YES];
[self.view addSubview:tempIV];
Step 3 : Define following touch methods to handle movement of image for Drag & Drop
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
if([[touch view] tag] == 100)
{
[tempIV setImage:ivSource1.image];
[tempIV setCenter:[touch locationInView:self.view]];
}
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
[tempIV setCenter:[touch locationInView:self.view]];
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [touches anyObject];
[tempIV setCenter:[touch locationInView:self.view]];
if(CGRectContainsPoint(ivDestination2.frame, [touch locationInView:self.view]))
{
[ivDestination2 setImage:tempIV.image];
}
// Remove image from dragable view
[tempIV setImage:[UIImage imageNamed:#""]];
}

Answer 2

With iOS 13, you can use Drag & Drop and copy/paste APIs in order to perform a drag and drop operation of a UIImage from one UIImageView to another UIImageView. According to your needs, you may choose one of the two following Swift 5.1 implementations.
#1. Using UIDragInteraction, UIDragInteractionDelegate and UIPasteConfiguration
import UIKit
class ViewController: UIViewController {
let imageView1 = UIImageView()
let imageView2 = UIImageView()
override func viewDidLoad() {
super.viewDidLoad()
imageView1.image = UIImage(named: "image")
imageView1.contentMode = .scaleAspectFit
imageView1.isUserInteractionEnabled = true
let dragInteraction = UIDragInteraction(delegate: self)
dragInteraction.isEnabled = true
imageView1.addInteraction(dragInteraction)
imageView2.contentMode = .scaleAspectFit
imageView2.isUserInteractionEnabled = true
let configuration = UIPasteConfiguration(forAccepting: UIImage.self)
imageView2.pasteConfiguration = configuration
let stackView = UIStackView(arrangedSubviews: [imageView1, imageView2])
view.addSubview(stackView)
stackView.distribution = .fillEqually
stackView.frame = view.bounds
stackView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
}
override func paste(itemProviders: [NSItemProvider]) {
_ = itemProviders.first?.loadObject(ofClass: UIImage.self, completionHandler: { (image: NSItemProviderReading?, error: Error?) in
DispatchQueue.main.async {
self.imageView2.image = image as? UIImage
}
})
}
}
extension ViewController: UIDragInteractionDelegate {
func dragInteraction(_ interaction: UIDragInteraction, itemsForBeginning session: UIDragSession) -> [UIDragItem] {
guard let image = imageView1.image else { return [] }
let item = UIDragItem(itemProvider: NSItemProvider(object: image))
return [item]
}
}
#2. Using UIDragInteraction, UIDragInteractionDelegate, UIDropInteraction and UIDropInteractionDelegate
import UIKit
class ViewController: UIViewController {
let imageView1 = UIImageView()
let imageView2 = UIImageView()
override func viewDidLoad() {
super.viewDidLoad()
imageView1.image = UIImage(named: "image")
imageView1.contentMode = .scaleAspectFit
imageView1.isUserInteractionEnabled = true
imageView2.contentMode = .scaleAspectFit
imageView2.isUserInteractionEnabled = true
let dragInteraction = UIDragInteraction(delegate: self)
dragInteraction.isEnabled = true
imageView1.addInteraction(dragInteraction)
let dropInteraction = UIDropInteraction(delegate: self)
imageView2.addInteraction(dropInteraction)
let stackView = UIStackView(arrangedSubviews: [imageView1, imageView2])
view.addSubview(stackView)
stackView.distribution = .fillEqually
stackView.frame = view.bounds
stackView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
}
}
extension ViewController: UIDragInteractionDelegate {
func dragInteraction(_ interaction: UIDragInteraction, itemsForBeginning session: UIDragSession) -> [UIDragItem] {
guard let image = imageView1.image else { return [] }
let item = UIDragItem(itemProvider: NSItemProvider(object: image))
item.localObject = image
return [item]
}
}
extension ViewController: UIDropInteractionDelegate {
func dropInteraction(_ interaction: UIDropInteraction, canHandle session: UIDropSession) -> Bool {
return session.canLoadObjects(ofClass: UIImage.self) && session.items.count == 1
}
func dropInteraction(_ interaction: UIDropInteraction, sessionDidUpdate session: UIDropSession) -> UIDropProposal {
let dropLocation = session.location(in: view)
let operation: UIDropOperation
if imageView2.frame.contains(dropLocation) {
operation = session.localDragSession == nil ? .copy : .move
} else {
operation = .cancel
}
return UIDropProposal(operation: operation)
}
func dropInteraction(_ interaction: UIDropInteraction, performDrop session: UIDropSession) {
session.loadObjects(ofClass: UIImage.self) { imageItems in
guard let images = imageItems as? [UIImage] else { return }
self.imageView2.image = images.first
}
}
}