iOS Array of UIImageView's

[DataBits]

Is is possible to create an array of UIImageView's? If so, how is it declared and implemented?

For example:

UIImageView *oneView
UIImageView *twoView
UIImageView *threeView

rewritten would result in something like: UIImageView *mynumberView[3]

Thanks.

 

[nacho4d]

2 ways

The simplest way is to use arrays like C.
declare it this way :

UIImageView *imageViewArray[3];

and then call it like this:

imageView[0] = [UIImageView alloc] initWithSomething];

Or if you want to use some classes, then use NSArray or NSMutableArray.

ie:

NSMutableArray * imagesArray;

imagesArray = [[NSMutableArray alloc] init];

UIImageView *oneImage = [[UIImageView alloc] initWithSomething];
[imagesArray addObject:oneImage];
[oneImage release];

UIImageView *Imagetwo = ... (do the same as above)

this solved your question?

 

[DataBits]

Yes, thank you nacho.

 

[sgiard]

Newbie question

Hi everybody.

I'm new to the iPhone and objective C so I'm sorry if this sounds like a stupid question.

I'm trying to modify the Touches sample for the iPhone.

Originally the code is:

@interface MyView()
@property (nonatomic, retain) UIImageView *firstPieceView;
@property (nonatomic, retain) UIImageView *secondPieceView;
@property (nonatomic, retain) UIImageView *thirdPieceView;
@property (nonatomic, retain) UILabel *touchPhaseText;
@property (nonatomic, retain) UILabel *touchInfoText;
@property (nonatomic, retain) UILabel *touchTrackingText;
@property (nonatomic, retain) UILabel *touchInstructionsText;
@property (nonatomic) BOOL piecesOnTop;
@property (nonatomic) CGPoint startTouchPosition;
@end

I want to have an array of 3 (or n) PieceView instead of firstPieceView, secondPieceView and thirdPieceView

if I put:

@property (nonatomic, retain) UIImageView *PieceView[3];
(and change the .h file accordingly)

I get the error:

bad property declaration

What don't I know that causes this?

Thanx...

 

[nacho4d]

This might help

, I have tried to do that some time in the past and I remember to have the same error.I think that objective-C compiler don't accept that kind of property declaration. I can't certainly tell.

As I suggested before, you can always NSArray, (Or NSMutableArray) to have n elements UIImageView.

Just use
myArray = [NSMutableArray array]; //if need retain it.
[myArray addObject:someUIImageView];
.
.
.
and then retreive it by:

UIImageView *myImage = [myArray objectAtIndex:i];

And problem solved! 😉
Using NSArray class and its subclass NSMutableArray is very easy.

In this case you probably won't need any UIImageView member variable or property.
And you probably you could use: (not tested but surely could)

#define firstOne [myArray objectAtIndex:0]
#define secondOne [myArray objectAtIndex:1]

Or, What I did in my case, I did realize that there was no need of making PieceView[3] a property (Because at first I tended to make all my variables properties).So did it with out properties.
Using PieceView for retrieving the i-th image as I suppose you are trying to do.

Please note that making something a property only is needed when it's going to be called or used from outside that class.
Good Luck

 

[sgiard]

It works!!!

Thank you so much for the quick response...

Everything works great now. 😀

Just a quick follow up question if I may...

the old code read:

// Releases necessary resources.
- (void)dealloc
{
// Release each of the subviews
[firstPieceView release];
[secondPieceView release];
[thirdPieceView release];

...
}

can I just replace this with:

// Releases necessary resources.
- (void)dealloc
{
// Release each of the subviews
[myArray release];

...
}

or do I have to write a loop to release each UIImageView of the array and then release the array?

 

[nacho4d]

you're welcome

When releasing, it should be enough to release the array. (any loop is not necessary)
Actually it depends on how you put your objects in the array.
for example.
//somewhere inside interface:
@property (retain) NSArray *arr;
.
.
.
//inside implementation:

UIImageView *img1 = [[UIImageView alloc] init];
//the retain count should be 1,
//then create an array an set your array property
NSMutableArray *_arr = [[NSMutableArray alloc] init];
self.arr = _arr;
[_arr release];
[arr addObject:img1];
//then the retain count of img1 should be 2
[img1 release];
//img1 retain count became 1 again.

//and in your dealloc method:
[arr release];
[super dealloc];
//img1 and arr's retain count should be 0 then everything goes just fine (No leaks)

A good rule is that you release properties inside dealloc method. And not all the variables you used somewhere else. (because they will be out of scope 😉 and should have been released before )


Maybe this example was not clear enough...
Try reading some Memory management stuff... I remember I learned a lot from Kochan's book, Programming in Objective-C.

 

[sgiard]

Ok

Thanks again so much...

 

[sanniv]

Problem solved

Finally got the right way to use UIImageView, I explained here-- http://www.sannivs-iphone-programming-tips.blogspot.com/