releasing all cells in tableview ios iphone

i got mem leaking problem discovered with profiling in xcode. The problem it's quite easy but i ca开发者_高级运维n'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

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.

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];
}

I would replace this line:

else img= [[UIImage alloc] initWithData:data];

with:

else img= [UIImage imageWithData:data];

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.