Question

I believe I may be dealing with some view issues which are not allowing me to detect and add UIImageView objects to an array. I could really use some suggestions.

I’ve got a number of UIImageViews with images linked to a UIView that sits on top of a UIViewController (the UIView was added to help with drawRect and some additional advantages). So, when I touch an image and ‘drag and drop’ it, I want to add that image to an array upon being dropped.

My touchesBegan gets the location of the touch and checks UIImageView is being touched and then centers on that view as follows:

-(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

            UITouch *touch = [[event allTouches] anyObject];

            CGPoint location = [touch locationInView:self];  //can't use self.view in a UIView, this may be causing issues?

            startLocation = location;  // for reference as needed



    NSLog(@"Image x coord:   %f", location.x);

    NSLog(@"Image y coord:   %f", location.y);

    if ([touch view] == obiWan_Block)

            {obiWan_Block.center = location;}

    else if ([touch view] == r2d2_Block)

            {r2d2_Block.center = location;}

    else if ([touch view] == you_Block)

            {you_Block.center = location;}

}

Then, I drag the UIImageView around with touchesMoved and finally, ‘drop’ the image with touchesEnded. When the UIImageView is drop in a certain area of the screen, I ‘snap’ it to a specific location. It’s at this point I want to place this UIImageView into an array, but I’m having no luck. I believe I’m getting confused on the various views being touched and what’s getting added via addObject to my NSMutableArray. Or, I could be missing something completely. Here’s my touchedEnded method:

-(void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {

          UITouch *touch = [[event allTouches] anyObject];

          CGPoint location = [touch locationInView:self];

          UIView *temp = [touch view];

          UIImageView *currentImageView = (UIImageView *)[touch view];  //DON'T THINK THIS IS RIGHT

    NSLog(@"Current Image View is:   %@", currentImageView);

    if ((location.x > dropZone.origin.x) && (location.y >= dropZone.origin.y) && ([touch view] != NULL))

        {

            CGRect frame = temp.frame;

            if (touchCount == 0) {

                frame.origin.x = 15;

                frame.origin.y = 180;

                temp.frame = frame;

                [quoteArray addObject: currentImageView];

                touchCount++;

                }

            else if (touchCount == 1) {

                frame.origin.x = 70;

                frame.origin.y = 180;

                temp.frame = frame;

                [quoteArray addObject: currentImageView]; 

                touchCount++;

                }

                ....

I have an NSLog statement to check if addObject is working as follows:

NSLog(@"the quote array contains %d items. Contents = %@",[quoteArray count], quoteArray);

The log always says:

the quote array contains 0 items. Contents = (null)

Please advise and thanks!

Answer 1

Your last part of code shows that you have uninitialized quoteArray. Check code when you create it, I guess you missed something in your init method. Because if array was correct then NSLog should show below:

NSArray *quoteArray = [NSArray array];
NSLog(@"%@", quoteArray); 

2011-11-17 17:37:00.506 TestApp[1382:207] ( )