Rotation UIView iOS error when try to drag and drop object

Question

i have an UIView subclass for drag and drop object, it's work all perfectly but after i apply this transformation

    CGAffineTransform transform = CGAffineTransformMakeRotation(M_PI_2);
    self.transform = transform;

When go to drag and drop, object start an infinite spiral :-/

Touch Began

if (!moveObject){

    CGAffineTransform transform = CGAffineTransformMakeRotation(M_PI_2);
    self.transform = transform;

}else{

    // When a touch starts, get the current location in the view
    currentPoint = [[touches anyObject] locationInView:self];
}

Touch moved code is here

if (moveObject){

    //Current point is locationInView get in touchBegin
    // Get active location upon move
    CGPoint activePoint = [[touches anyObject] locationInView:self];

    // Determine new point based on where the touch is now located
    CGPoint newPoint = CGPointMake(self.center.x + (activePoint.x - currentPoint.x),
                                   self.center.y + (activePoint.y - currentPoint.y));
    // Set new center location
    self.center = newPoint;
}

How i can resolve this?

P.S. moveObject is declared elsewhere, and is correctly set YES/NO.

I don't want move and rotate object at same time, only 1 thing per time. When i rotate UIView i want to maintain a new orientation and i must be able to move object with new orientation.

ADDED Here my xcode project example. https://www.dropbox.com/s/lza1n9kjnxa4zun/xcode.zip

@Ossir in touchesBegan if a boolean flag is true i made the transformation else i move the object — , Jan 18 '14 at 19:35
The code you posted is ok. You should show us code with this check before applying transformation and the code where you're changing this boolean. The error is there, I guess=) — Ossir, Jan 18 '14 at 19:38
Where you change `moveObject` to `YES` ? Try to do it right after `self.transform = transform;` — Ossir, Jan 18 '14 at 19:44
@Ossir i change moveObject by UIButton action, when button is OFF can move, when button is ON i set moveObject to YES and can rotate uiview, you cannot rotate and move at same time. — , Jan 18 '14 at 19:52
Oh, now I get it. So you want to different actions, I will change my answer then — Ossir, Jan 18 '14 at 19:53

score 1 · Answer 1 · answered Jan 18 '14 at 19:38

1

I tested this, and it works like charm:

- (void)viewDragged:(UIPanGestureRecognizer *)gesture
{

    CGPoint translation = [gesture translationInView:self.view];

    gesture.view.center = CGPointMake(gesture.view.center.x + translation.x, gesture.view.center.y + translation.y);


    [gesture setTranslation:CGPointZero inView:gesture.view];

}

answered Jan 18 '14 at 19:38

Albara

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14

but now i use touches method for drag and drop my object not gesture recognizer – Jan 18 '14 at 19:41

Ossir · Answer 2 · 2014-01-18T20:08:59.290

EDITED Now when we know more info...

If you want two different action with some sort of switcher as moveObject you need to move all your code into else block:

if (!moveObject){
    CGAffineTransform transform = CGAffineTransformMakeRotation(M_PI_2);
    self.transform = transform;
} 
else {
    // When a touch starts, get the current location in the view
    currentPoint = [[touches anyObject] locationInView:self];
    //Current point is locationInView get in touchBegin
    // Get active location upon move
    CGPoint activePoint = [[touches anyObject] locationInView:self];

    // Determine new point based on where the touch is now located
    CGPoint newPoint = CGPointMake(self.center.x + (activePoint.x - currentPoint.x),
                                   self.center.y + (activePoint.y - currentPoint.y));
    // Set new center location
    self.center = newPoint;
}

Or even better, If you want to rotate your view on 90 degrees every touch, then change transformation code to this:

if (!moveObject){
    self.transform = CGAffineTransformRotate(self.transform, M_PI_2);
}
else {
    ….
}

You can set lesser value instead of M_PI_2 to achieve slow rotation while panning with your finger=)

I insert currentPoint = [[touches anyObject] locationInView:self]; outside but not work, also moveObject is correctly set to YES or NO, i not forgot. — , Jan 18 '14 at 19:56
Also check out answer from @Unheilig it will be definitely your next problem=) — Ossir, Jan 18 '14 at 20:01

Rotation UIView iOS error when try to drag and drop object

2 Answers2