How to let the user add objects

[vincefried]

Hello iPhoneDevSDK-Community!

My question: How can i let the user add a uiimageview by clicking a "+"-button. If the user clicks this button again, a second uiimageview should appear and so on...

Thanks!
vincefried

[baja_yu]

Alloc/init a new imageview just like any other object, set the image, then add it as a subview of the view where you want to show it.

[vincefried]

Thanks! That's what I did now:

-(IBAction) addObject:(id)sender {
    
    UIImageView *newImageView = [[UIImageView alloc] initWithImage: [UIImage imageNamed:@"Stuhl.png"]];
    newImageView.userInteractionEnabled = TRUE;
    [theView addSubview:newImageView];

    imageViewGlobal = newImageView;
    
}

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

	UITouch *touch = [[event allTouches] anyObject];
	CGPoint touchLocation = [touch locationInView:self.view];
	
	if ([touch view] == imageViewGlobal) {
        
        imageViewGlobal.center = touchLocation;
        
    }
}

My problem is, when I created multiple imageviews with multiple clicks on the "+"-button, i just can move the latest one, I created... how can I solve this problem?

Thanks!

[baja_yu]

Is imageViewGlobal an instance variable? You know that you are leaking object there, right? You never release previous ones. And if you are creating more of them, you can't just use a single one, you need an array. When a touch is detected you need to identify which image is touched and then move that image. There's a sample code project in the documentation called Touches which pretty much does just that.

[vincefried]

I know how to detect which image is moving, but the problem is when I create the objects with the interface builder, I declare them in the header file and know the names of the imageViews, but when the user created the imageViews by clicking a button, the objects aren't declared in the header file. How can I differentiate the objects, if they don't have a name?

[baja_yu]

Arrays...

[vincefried]

Yes, but how can I use arrays for that? In the Touches example code, they didn't use a function to add or delete objects... I only know how to use arrays for a tableview.

[baja_yu]

They didn't because they only have a 3 imageviews and that's it. How to use it? When you create a new view add it to the array as well.

[vincefried]

Like that?

-(IBAction) addObject:(id)sender {
    
    UIImage * image = [UIImage imageNamed:@"Stuhl.png"];
    CGRect rect = CGRectMake(0.0f, 40.0f, image.size.width, image.size.height);
    
    UIImageView * newImageView = [[UIImageView alloc] initWithFrame:rect];
    [newImageView setImage:image];
    [theView addSubview:newImageView];
    newImageView.userInteractionEnabled = TRUE;

    [myArray addObject:newImageView];  
    
}

But now I have this method

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{    
    // if the gesture recognizers's view isn't one of our pieces, don't allow simultaneous recognition
    if (gestureRecognizer.view != ???)
    
    // if the gesture recognizers are on different views, don't allow simultaneous recognition
    if (gestureRecognizer.view != otherGestureRecognizer.view)
        return NO;
    
    // if either of the gesture recognizers is the long press, don't allow simultaneous recognition
    if ([gestureRecognizer isKindOfClass:[UILongPressGestureRecognizer class]] || [otherGestureRecognizer isKindOfClass:[UILongPressGestureRecognizer class]])
        return NO;
    
    return YES;
}

What do I have to insert for the ??? if I don't have a name for the image?

[baja_yu]

You aren't, and shouldn't be, working with names. You work with pointers to objects. Each element the array will be a pointer to a uiimageview object, so will the gesutre recognizer's view property, so compare those by looping through the array.

Also, you're still leaking the newly created imageviews.

[vincefried]

Here's what I did so far:

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{       
    arryData = [[NSMutableArray alloc] init]; 
    NSString *str = [NSString stringWithFormat:@"%@", [arryData count]];
    UIImage *image = [UIImage imageNamed:str];
    [imageViewGlobal setImage:image];
    
    if (gestureRecognizer.view != imageView && gestureRecognizer.view != imageView2 && gestureRecognizer.view != imageViewGlobal)
        return NO;
    
    if (gestureRecognizer.view != otherGestureRecognizer.view)
        return NO;
    
    if ([gestureRecognizer isKindOfClass:[UILongPressGestureRecognizer class]] || [otherGestureRecognizer isKindOfClass:[UILongPressGestureRecognizer class]])
        return NO;

    return YES;
}


-(IBAction) addObject:(id)sender {
   
    arryData = [[NSMutableArray alloc] init];
    int i;
    for (i = 0; i < 1; i++) {
        
        UIImage * image = [UIImage imageNamed:@"Stuhl.png"];
        CGRect rect = CGRectMake(0.0f, 40.0f, image.size.width, image.size.height);
        UIImageView * newImageView = [[UIImageView alloc] initWithFrame:rect];
        [newImageView setImage:[UIImage imageNamed:@"Stuhl.png"]];
        //newImageView.userInteractionEnabled = TRUE;
        [theView addSubview:newImageView];
        [arryData addObject:newImageView];

    }
    
}

It still doesn't work...

[baja_yu]

Where and how is arrayData declared?

By doing this

arryData = [[NSMutableArray alloc] init];

you are creating a new array each time, and most likely leaking the previous one at the same time. You should be creating it once, probably on viewDidLoad, and just adding to it from then on.
In the addObject: method in the for loop you never release the imageviews hence leaking them. You also never use 'image' from the first line of the for block.

[vincefried]

Originally Posted by baja_yu

Where and how is arrayData declared?

In the header file

 NSMutableArray *arryData;

Originally Posted by baja_yu

In the addObject: method in the for loop you never release the imageviews hence leaking them.

Yes, I know. That's because of Xcode 4.2. The compiler, it uses forbids releasing objects. Everytime I try to do it, I get an errormessage.

Originally Posted by baja_yu

You also never use 'image' from the first line of the for block.

I do, but it's not that necessary.

 image.size.height

[baja_yu]

Originally Posted by vincefried

In the header file

 NSMutableArray *arryData;

Then you're leaking arrays with every subsequent call, and if you don't release in dealloc you're leaking the first one as well.

Originally Posted by vincefried

Yes, I know. That's because of Xcode 4.2. The compiler, it uses forbids releasing objects. Everytime I try to do it, I get an errormessage.

Please tell me that you're not actually blaming the compiler for your lack of memory management knowledge, or are you using ARC. What's the error?

Originally Posted by vincefried

I do, but it's not that necessary.

 image.size.height

In that case you should use 'image' in the 'newImageView setImage:' call instead of calling imageNamed again.

[vincefried]

First, thanks for your engagement!

Originally Posted by baja_yu

Please tell me that you're not actually blaming the compiler for your lack of memory management knowledge, or are you using ARC. What's the error?

I am using ARC.. It thought that was a new thing of Xcode 4.2 that should make programming more simple. I think I'm wrong, right?

Error:"ARC forbids explicit message send of 'release'"

Originally Posted by baja_yu

In that case you should use 'image' in the 'newImageView setImage:' call instead of calling imageNamed again.

-(IBAction) addObject:(id)sender {

***int i;
***for (i = 0; i < 1; i++) {

*******UIImage * image = [UIImage imageNamed:@"Stuhl.png"];
*******CGRect rect = CGRectMake(0.0f, 40.0f, image.size.width, image.size.height);
*******UIImageView * newImageView = [[UIImageView alloc] initWithFrame:rect];
*******[newImageView setImage:image];
*******newImageView.userInteractionEnabled = TRUE;
*******[theView addSubview:newImageView];
*******[arryData addObject:newImageView];

***}

}

Sure.. thanks.

[vincefried]

Don't worry about the **** that's because I wrote
the reply with my iPhone.

[baja_yu]

Originally Posted by vincefried

I am using ARC.. It thought that was a new thing of Xcode 4.2 that should make programming more simple. I think I'm wrong, right?

They say it is, but I'm not sure yet

That code now looks better, but you're still creating a new array every time the gesture recognizer triggers. You should probably do it in initWithNibName (or Coder, whichever init you use) and be done with it.
Also, there seems to be no point to the for loop in that IBAction method since you hardcoded the start value to 0 and and the condition to <1, it will always run just once so you might as well remove it.

[vincefried]

Originally Posted by baja_yu

you're still creating a new array every time the gesture recognizer triggers.

You mean this?

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{       
    NSString *str = [NSString stringWithFormat:@"%@", [arryData count]];
    UIImage *image = [UIImage imageNamed:str];
    [imageViewGlobal setImage:image];
    
    if (gestureRecognizer.view != imageView && gestureRecognizer.view != imageView2 && gestureRecognizer.view != imageViewGlobal)
        return NO;
    
    if (gestureRecognizer.view != otherGestureRecognizer.view)
        return NO;
    
    if ([gestureRecognizer isKindOfClass:[UILongPressGestureRecognizer class]] || [otherGestureRecognizer isKindOfClass:[UILongPressGestureRecognizer class]])
        return NO;

    return YES;
}

I did that, because I still was not really sure about what to insert for imageViewGlobal

Originally Posted by baja_yu

You should probably do it in initWithNibName (or Coder, whichever init you use) and be done with it.

Like that?

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    
    
        // Custom initialization of my two tab items on the tabbar controller
        MyView *mView = [[MyView alloc] initWithNibName:@"ViewController_iPad" bundle:nil];
        
        NSMutableArray *array = [[NSMutableArray alloc] initWithObjects:mView, nil];
        arryData = array;
        
    
    return self;
}

Originally Posted by baja_yu

Also, there seems to be no point to the for loop in that IBAction method since you hardcoded the start value to 0 and and the condition to <1, it will always run just once so you might as well remove it.

Sorry, but I'm pretty confused now... I'm not that new to Objective C programming, but I just don't it at the moment.. I feel stupid.

[baja_yu]

Originally Posted by vincefried

Sorry, but I'm pretty confused now... I'm not that new to Objective C programming, but I just don't it at the moment.. I feel stupid.

This:

-(IBAction) addObject:(id)sender {
   //int i;
   //for (i = 0; i < 1; i++) {
      UIImage * image = [UIImage imageNamed:@"Stuhl.png"];
      CGRect rect = CGRectMake(0.0f, 40.0f, image.size.width, image.size.height);
      UIImageView * newImageView = [[UIImageView alloc] initWithFrame:rect];
      [newImageView setImage:image];
      newImageView.userInteractionEnabled = TRUE;
      [theView addSubview:newImageView];
      [arryData addObject:newImageView];
   //}
}

[vincefried]

When I press on my add-button, a new imageview appears, but I'm still not able to move it around...

[vincefried]

Never mind, I solved it by myself, but thanks for the answer. I just searched for the wrong method.

-(IBAction) addObject:(id)sender {

    UIImage * image = [UIImage imageNamed:@"Stuhl.png"];
    CGRect rect = CGRectMake(0.0f, 40.0f, image.size.width, image.size.height);
    Bild *newImageView = [[Bild alloc] initWithFrame:rect];
    [newImageView setImage:image];
    newImageView.userInteractionEnabled = TRUE;
    [theView addSubview:newImageView];
    /*--->*/[self addGestureRecognizersToPiece:newImageView];/*<---*/

}