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/