CODEWITHSUNDEEP
iosobjective-c
m177312
m177312

Reputation: 1209

Save the position of a UIImageView

I have several UIImageViews that the user can drag, scale and rotate. I want the position, size and angle to persist when the user navigates to another view and comes back. How do i achieve this?

I have used the following code to pan, rotate and scale

- (void)panPiece:(UIPanGestureRecognizer *)gestureRecognizer
{
UIView *piece = [gestureRecognizer view];

[self adjustAnchorPointForGestureRecognizer:gestureRecognizer];

if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || [gestureRecognizer state] == UIGestureRecognizerStateChanged) {
    CGPoint translation = [gestureRecognizer translationInView:[piece superview]];

    [piece setCenter:CGPointMake([piece center].x + translation.x, [piece center].y + translation.y)];
    [gestureRecognizer setTranslation:CGPointZero inView:[piece superview]];
}
}


- (void)rotatePiece:(UIRotationGestureRecognizer *)gestureRecognizer
{
[self adjustAnchorPointForGestureRecognizer:gestureRecognizer];

if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || [gestureRecognizer state] == UIGestureRecognizerStateChanged) {
    [gestureRecognizer view].transform = CGAffineTransformRotate([[gestureRecognizer view] transform], [gestureRecognizer rotation]);
    [gestureRecognizer setRotation:0];
}
}


- (void)scalePiece:(UIPinchGestureRecognizer *)gestureRecognizer
{
[self adjustAnchorPointForGestureRecognizer:gestureRecognizer];

if ([gestureRecognizer state] == UIGestureRecognizerStateBegan || [gestureRecognizer state] == UIGestureRecognizerStateChanged) {
    [gestureRecognizer view].transform = CGAffineTransformScale([[gestureRecognizer view] transform], [gestureRecognizer scale], [gestureRecognizer scale]);
    [gestureRecognizer setScale:1];
}
}

Upvotes: 0

Views: 201

Answers (1)

dymv
dymv

Reputation: 3252

Depending on your needs you can create method, that you'll add as another target method to all your gesture recognizers.

E.g.

[panGestureRecognizer addTarget: self action: @selector(onGestureRecognizerEnd:)];
[rotationGestureRecognizer addTarget: self action: @selector(onGestureRecognizerEnd:)];
[pinchGestureRecognizer addTarget: self action: @selector(onGestureRecognizerEnd:)];


Sample implementation of that method could be:

- (void)onGestureRecognizerEnd: (UIGestureRecognizer *)gestureRecognizer
{
    switch ( gestureRecognizer.state )
    {
        case UIGestureRecognizerStateEnded:
        case UIGestureRecognizerStateCancelled:
        case UIGestureRecognizerStateFailed:
        {
            [self _saveViewPosition: gestureRecognizer.view];
            break;
        }
        default:
        {
            break;
        }
    }
}


_saveViewPosition: method you can implement like this:

- (void)_saveViewPosition: (UIView *)view
{
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

    [defaults setObject: [NSKeyedArchiver archivedDataWithRootObject: [NSValue valueWithCGPoint: view.center]]
                 forKey: [self _centerKeyForView: view]];
    [defaults setObject: [NSKeyedArchiver archivedDataWithRootObject: [NSValue valueWithCGAffineTransform: view.transform]]
                 forKey: [self _transformKeyForView: view]];
}


For more information check Xcode project.

BR

Upvotes: 1

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