how to alter NSMutableArray in an specific array

Question

I have a NSMutableArray which holds a Custom class of MKMapkit.

MapPoint *placeObject = [[MapPoint alloc] initWithTitle:title subtitle:subtitle coordinate:loc description:description storeImage:storeImage];
[annotationArray addObject:placeObject];

My routine fills the placeObject without the image because they will load asynchronously and finished after a couple of seconds. Now my questions is: Is there a way to alter the placeObject which is within the annotationArray?

EDIT

To display my issue in a better way here some code parts:

if (annotationArray == nil)
{
    [self setAnnotationArray:[[NSMutableArray alloc] init]];
}
for (NSDictionary *locationDetails in parser.items)
{
    __block NSData *storeImageData;
    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0);
    dispatch_async(queue, ^{
        storeImageData = [NSData dataWithContentsOfURL:storeImageURL];
        
        dispatch_sync(dispatch_get_main_queue(), ^{
            UIImage *storeImageTMP = [UIImage imageWithData:storeImageData];
            counterBlock ++;
            NSLog(@"async: %d", counterBlock);
            [imageArray addObject:storeImageTMP];
            });
        });
MapPoint *placeObject = [[MapPoint alloc] initWithTitle:title subtitle:subtitle coordinate:loc description:description storeImage:storeImage];
[annotationArray addObject:placeObject];
}
[mapView addAnnotations:annotationArray];

after this is done: dispatch_queue_t will start working. So I check every 2 seconds if its fully loaded. Then I start to alter annotationArray and refresh my annotations (remove all -> add to map which additional image)

- (void) checkMap
{
    if (counterBlock == 547)
    {
        for (int i=0; i<=counterBlock; i++)
        {
            MapPoint *point = annotationArray[i];
            point.storeImage = imageArray[i];
        }
        if(timer)
        {
            [timer invalidate];
            timer = nil;
        }
        [mapView removeAnnotations:mapView.annotations];
        [mapView addAnnotations:annotationArray];
    }
}

Just alter it. It's a pointer stored in the array, not a copy of the placeObject. Whatever you do to the original will "appear" in the version accessed through the array (since they will be the same object). — Hot Licks
– Hot Licks, Commented May 2, 2013 at 17:00

rmaddy · Accepted Answer · 2013-05-02 15:57:25Z

4

All you need to do is get a reference to one of the MapPoint objects in the array. Then you can set properties and/or call methods on the object as needed.

MapPoint *point = annotationArray[x]; // x is whatever index you need
point.image = ... // some image

answered May 2, 2013 at 15:57

rmaddy

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6 Comments

rmaddy Over a year ago

Are you sure that annotationArray isn't nil?

CTSchmidt Over a year ago

I updatet my question annotationArray isn't nil, only the space for the Image

rmaddy Over a year ago

Did you use @synthesize and/or explicitly create your own ivar for the annotationArray property? It's possible the backing ivar is really _annotationArray. If you have a property then use it. Change everything to self.annotationArray to be sure.

CTSchmidt Over a year ago

self. effect nothing and annotationArray is synthesized

CTSchmidt Over a year ago

I found the issue: imageArray is nil in checkMap but why?

|

remy_jourde · Accepted Answer · 2013-05-02 16:02:58Z

0

You can retrieve from your mutable array, the object you want to alter with the objectAtIndex method

NSInteger indexofMyObject = 0;
MapPoint *point = [myArray objectAtIndex:indexofMyObject];

answered May 2, 2013 at 16:02

remy_jourde

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Comments

NSNolan · Accepted Answer · 2013-05-02 16:36:42Z

0

Your MapPoint instance placeObject is a pointer. So adding it to the array does not copy placeObject by value, but actually holds its address. Getting the address of the object from the array will allow you to manipulate it.

annotationArray[objectIndex].anything = anything you want

answered May 2, 2013 at 16:36

NSNolan

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