Question

http://developer.apple.com/library/ios/#samplecode/Touches/Introduction/Intro.html

I’m new to IOS development, and have been playing around with the IOS dev sample code, trying to learn how things work, etc… I came across this sample code (the classic version, not the gesture recognizers ver.) that does everything I’m looking for, except one thing. When the image views are dragged over another image view, they begin stacking up, and you have to double click the image to separate them.

I’ve spent forever trying to figure out how to make them not stack up. I think I have to store that a piece is getting being moved in an ivar, and stop it from getting the position of the other views… But I’m not sure how to go about doing it. If someone has the time to modify the sample code to not stack pieces, I’d really appreciate it! I’m dying to find out the solution after the forever I spent trying to do it!

I’ll try to be a little specific with what I’m trying to do here… I’ve made 26 of these image views, making them each a letter of the alphabet. I have 13 image views in two rows. A-M & N-Z. Currently, if I drag the A tile down from the top row, moving it down to a “spelling area” I have to cross over the N-Z row. When I do, the “A” tile (image view) picks up any tile it hovers over. So if I drag the A straight down, it’s going to pick up the N tile, because it’s going to hover right over it, before getting down to the “spelling” area.

Thanks in advance for any help or direction you can give me!

Answer 1

Well you have this function in the sample code

// Checks to see which view, or views,  the point is in and then calls a method to perform the closing animation,
// which is to return the piece to its original size, as if it is being put down by the user.
-(void)dispatchTouchEndEvent:(UIView *)theView toPosition:(CGPoint)position
{   
    // Check to see which view, or views,  the point is in and then animate to that position.
    if (CGRectContainsPoint([firstPieceView frame], position)) {
        [self animateView:firstPieceView toPosition: position];
    } 
    if (CGRectContainsPoint([secondPieceView frame], position)) {
        [self animateView:secondPieceView toPosition: position];
    } 
    if (CGRectContainsPoint([thirdPieceView frame], position)) {
        [self animateView:thirdPieceView toPosition: position];
    }
    // If one piece obscures another, display a message so the user can move the pieces apart
    if (CGPointEqualToPoint(firstPieceView.center, secondPieceView.center) ||
        CGPointEqualToPoint(firstPieceView.center, thirdPieceView.center) ||
        CGPointEqualToPoint(secondPieceView.center, thirdPieceView.center)) {
        touchInstructionsText.text = @"Double tap the background to move the pieces apart.";
        piecesOnTop = YES;
    } else {
        piecesOnTop = NO;
    }
}

wich you can try to modify to

// Checks to see which view, or views,  the point is in and then calls a method to perform the closing animation,
// which is to return the piece to its original size, as if it is being put down by the user.
-(void)dispatchTouchEndEvent:(UIView *)theView toPosition:(CGPoint)position
{   
    // Check to see which view, or views,  the point is in and then animate to that position.
    if (CGRectContainsPoint([firstPieceView frame], position)) {
        [self animateView:firstPieceView toPosition: position];
    } 
    if (CGRectContainsPoint([secondPieceView frame], position)) {
        [self animateView:secondPieceView toPosition: position];
    } 
    if (CGRectContainsPoint([thirdPieceView frame], position)) {
        [self animateView:thirdPieceView toPosition: position];
    }
    // If one piece obscures another, display a message so the user can move the pieces apart
    if (CGPointEqualToPoint(firstPieceView.center, secondPieceView.center) ||
        CGPointEqualToPoint(firstPieceView.center, thirdPieceView.center) ||
        CGPointEqualToPoint(secondPieceView.center, thirdPieceView.center)) {

        if (firstPieceView.center.x == secondPieceView.center.x)
            secondPieceView.center = CGPointMake(firstPieceView.center.x - 50, firstPieceView.center.y - 50);       
        if (firstPieceView.center.x == thirdPieceView.center.x)
            thirdPieceView.center  = CGPointMake(firstPieceView.center.x + 50, firstPieceView.center.y + 50);   
        if (secondPieceView.center.x == thirdPieceView.center.x)
            thirdPieceView.center  = CGPointMake(secondPieceView.center.x + 50, secondPieceView.center.y + 50);
        touchInstructionsText.text = @"";
    } else {
        piecesOnTop = NO;
    }
}

Let me know if it does what you want…