releasing all cells in tableview ios iphone - iphone

Question

i got mem leaking problem discovered with profiling in xcode. The problem it's quite easy but i can't understand how fix it:
Consider a uiviewcontroller with 2 button and a tableview.
button1=load JSON data from server and add cells to tableview then [tableview reloadData]
button2=load JSON data from another server and add cells to tableview then reload.
ok the problem is in:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
....
.....
NSURL *url = [NSURL URLWithString:stringpath];
NSData *data = [NSData dataWithContentsOfURL:url];
UIImage *img;
if(!data) img=[UIImage imageNamed:#"small.jpg"];
else img= [[UIImage alloc] initWithData:data];
cell.imageView.image = img;
Ok now if i start to switch with 2 button everytime i switch i got leaking from UIImage, so i think i need to "purge" (release) all cells data before reloading?
Thx

Answer 1

You should be releasing the img object after setting it in cell.imageView.image. I prefer to autorelease on the same line as it makes it easier for me to keep track.
UIImage *img;
if(!data) img=[UIImage imageNamed:#"small.jpg"];
else img= [[[UIImage alloc] initWithData:data] autorelease];
cell.imageView.image = img;
As mentioned in another answer, you can save yourself the pain by not using the initWithData call, but instead imageWithData.
The cells will take care of themselves.

Answer 2

The issue is not releasing img,plz use below
if (!data)
{
img = [UIImage imageNamed:#"small.jpg"];
cell.imageView.image = img;
}
else
{
img = [[UIImage alloc] initWithData:data];
cell.imageView.image = img;
[img release];
}

Answer 3

I would replace this line:
else img= [[UIImage alloc] initWithData:data];
with:
else img= [UIImage imageWithData:data];

Answer 4

You don't have to allocate memory for UIImage. You can perform the above implementation as follows :
NSData *data = [NSData dataWithContentsOfURL:url];
cell.imageView.image = [UIImage imageWithData: data];
Try this.