IPhone - Images making scrolling and other functionality to crash - iphone

Question

Everytime i load images in a tableview and try to scroll the table view i get a crash in my simulator but no errors are showing. Could this be that there is to much memory being used.
Below is the code for 1 out the three views:
#import "ResultViewController.h"
#import "JobAddSiteViewController.h"
#import "SpecificAddViewController.h"
#import "JobAddSiteAppDelegate.h"
#import "JSONKit.h"
#implementation ResultViewController
#synthesize listData;
#synthesize listLocation;
#synthesize listPostDate;
#synthesize listLogo;
#synthesize listDescription;
#synthesize uiTableView;
#synthesize buttonPrev;
#synthesize buttonNext;
NSInteger *countPage = 1;
NSMutableArray *tempArray;
NSMutableArray *tempArray2;
NSMutableArray *tempArray3;
NSMutableArray *tempArray4;
NSMutableArray *tempArray5;
-(IBAction)done{
JobAddSiteViewController *second = [[JobAddSiteViewController alloc]initWithNibName:nil bundle:nil];
[self presentModalViewController:second animated:YES];
[second release];
}
-(void)loadData{
NSString *strURL2 = [NSString stringWithFormat:#"http://www.bestitjobs.co.uk/totaljobs.php", ""];
NSData *nsData2 = [NSData dataWithContentsOfURL:[NSURL URLWithString: strURL2]];
NSString *dataResult = [[NSString alloc] initWithData:nsData2 encoding:NSUTF8StringEncoding];
tempArray = [[NSMutableArray alloc] init];
tempArray2 = [[NSMutableArray alloc] init];
tempArray3 = [[NSMutableArray alloc] init];
tempArray4 = [[NSMutableArray alloc] init];
tempArray5 = [[NSMutableArray alloc] init];
NSString *strURL = [NSString stringWithFormat:#"http://www.bestitjobs.co.uk/appresults3.php?pg=%d", countPage];
NSData *nsData = [NSData dataWithContentsOfURL:[NSURL URLWithString: strURL]];
NSDictionary *listDictionary = [nsData objectFromJSONData];
NSArray* people =[listDictionary objectForKey:#"jobs"];
for (NSDictionary *person in people) {
NSString *str = [NSString stringWithFormat:#"%#", [person valueForKey:#"position"]];
NSString *str2 = [NSString stringWithFormat:#"%#", [person valueForKey:#"subcounty"]];
NSString *str3 = [NSString stringWithFormat:#"%#", [person valueForKey:#"postdate"]];
NSString *str4 = [NSString stringWithFormat:#"%#", [person valueForKey:#"logo"]];
NSString *str5 = [NSString stringWithFormat:#"%#", [person valueForKey:#"description"]];
if(![str isEqualToString:#"<null>"])
{
NSString *position = [person objectForKey:#"position"];
[tempArray addObject: position];
if(![str2 isEqualToString:#"<null>"])
{
NSString *subcounty = [person objectForKey:#"subcounty"];
[tempArray2 addObject: subcounty];
}
else{
[tempArray2 addObject: #"-"];
}
if(![str3 isEqualToString:#"<null>"])
{
NSString *postDate = [person objectForKey:#"postdate"];
[tempArray3 addObject: postDate];
}
else{
[tempArray3 addObject: #"-"];
}
if(![str4 isEqualToString:#"<null>"])
{
NSString *logo = [person objectForKey:#"logo"];
[tempArray4 addObject: [NSString stringWithFormat:#"http://www.bestitjobs.co.uk/employers/logo/Files/%#", logo]];
}
else{
[tempArray4 addObject: [NSString stringWithFormat:#"http://www.bestitjobs.co.uk/employers/logo/Files/%#", "noimage.gif"]];
}
if(![str5 isEqualToString:#"<null>"])
{
NSString *description = [person objectForKey:#"description"];
[tempArray5 addObject: description];
}
else{
[tempArray5 addObject: #"-"];
}
}
}
if (countPage == 1) {
[self.buttonPrev setEnabled:FALSE];
}
else {
[self.buttonPrev setEnabled:TRUE];
}
NSInteger val = [dataResult intValue];
NSInteger pageEnd = val/10;
if (countPage < pageEnd) {
[self.buttonNext setEnabled:TRUE];
}
else {
[self.buttonNext setEnabled:FALSE];
}
//NSMutableArray *array = [[NSMutableArray alloc] initWithObjects:#"iPhone", #"iPod",#"iPad",nil];
self.listData = tempArray;
self.listLocation = tempArray2;
self.listPostDate = tempArray3;
self.listLogo = tempArray4;
self.listDescription = tempArray5;
[self.listData release];
[self.listLocation release];
[self.listPostDate release];
[self.listLogo release];
[self.listDescription release];
tempArray = nil;
tempArray2 = nil;
tempArray3 = nil;
tempArray4 = nil;
tempArray5 = nil;
}
- (void)viewDidLoad {
[self loadData];
[super viewDidLoad];
}
- (void)dealloc {
[tempArray dealloc];
[tempArray2 dealloc];
[tempArray3 dealloc];
[tempArray4 dealloc];
[tempArray5 dealloc];
[self.listData dealloc];
[self.listLocation dealloc];
[self.listPostDate dealloc];
[self.listLogo dealloc];
[self.listDescription dealloc];
[super dealloc];
}
#pragma mark -
#pragma mark Table View Data Source Methods
- (IBAction)prev{
countPage = countPage - 1;
[self.listData removeAllObjects];
[self.listLocation removeAllObjects];
[self.listPostDate removeAllObjects];
[self.listLogo removeAllObjects];
//NSMutableArray *array = [[NSMutableArray alloc] initWithObjects:#"1", #"2",#"3",nil];
//self.listData = array;
[self loadData];
[self.uiTableView reloadData];
}
- (IBAction)next{
countPage = countPage + 1;
[self.listData removeAllObjects];
[self.listLocation removeAllObjects];
[self.listPostDate removeAllObjects];
[self.listLogo removeAllObjects];
//NSMutableArray *array = [[NSMutableArray alloc] initWithObjects:#"1", #"2",#"3",nil];
//self.listData = array;
[self loadData];
[self.uiTableView reloadData];
}
- (void)tableView:(UITableView*)tableView didSelectRowAtIndexPath:(NSIndexPath*)indexPath {
JobAddSiteAppDelegate *ja = (JobAddSiteAppDelegate *)[[UIApplication sharedApplication] delegate];
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
for (UIView *view in cell.contentView.subviews){
if ([view isKindOfClass:[UILabel class]]){
UILabel *label = (UILabel *)view;
if (label.tag == 1) {
ja.jobText = label.text;
}
if (label.tag == 2) {
ja.locationText = label.text;
}
if (label.tag == 3) {
ja.dateText = label.text;
}
if (label.tag == 4) {
}
if (label.tag == 5) {
ja.specificText = label.text;
}
}
if ([view isKindOfClass:[UIImageView class]]){
UIImageView *image = (UIImageView *)view;
if (image.tag = 4){
ja.logoText = image.image;
}
}
}
SpecificAddViewController *second = [[SpecificAddViewController alloc]initWithNibName:nil bundle:nil];
[self presentModalViewController:second animated:YES];
[second release];
}
- (NSInteger)tableView:(UITableView *)tableView
numberOfRowsInSection:(NSInteger)section
{
return [self.listData count];
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath
*)indexPath
{
if (indexPath.section == 1 && indexPath.row == 1) {
return 65;
}
return 65;
}
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *SimpleTableIdentifier = #"SimpleTableIdentifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:SimpleTableIdentifier];
UILabel *labelMain;
UILabel *labelLocation;
UILabel *labelDate;
UIImageView *image;
UILabel *ref;
if (cell == nil) {
cell = [[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:SimpleTableIdentifier] autorelease];
image = [[[UIImageView alloc] initWithFrame:CGRectMake(0,3,80,62)] autorelease];
image.tag = 4;
[cell.contentView addSubview:image];
labelMain = [[[UILabel alloc] initWithFrame:CGRectMake(90,3,200,20)] autorelease];
labelMain.tag = 1;
labelMain.font = [UIFont systemFontOfSize:14.0];
[cell.contentView addSubview:labelMain];
labelLocation = [[[UILabel alloc] initWithFrame:CGRectMake(90,20,200,20)] autorelease];
labelLocation.tag = 2;
labelLocation.font = [UIFont systemFontOfSize:12.0];
labelLocation.textColor = [UIColor darkGrayColor];
[cell.contentView addSubview:labelLocation];
labelDate = [[[UILabel alloc] initWithFrame:CGRectMake(90,40,200,20)] autorelease];
labelDate.tag = 3;
labelDate.font = [UIFont systemFontOfSize:12.0];
labelDate.textColor = [UIColor darkGrayColor];
[cell.contentView addSubview:labelDate];
ref = [[[UILabel alloc] initWithFrame:CGRectMake(0, 0, 0, 0)] autorelease];
ref.tag = 5;
[cell.contentView addSubview:ref];
}
[(UILabel *)[cell.contentView viewWithTag:1] setText:[self.listData objectAtIndex:indexPath.row]];
[(UILabel *)[cell.contentView viewWithTag:2] setText:[self.listLocation objectAtIndex:indexPath.row]];
[(UILabel *)[cell.contentView viewWithTag:3] setText:[self.listPostDate objectAtIndex:indexPath.row]];
[(UILabel *)[cell.contentView viewWithTag:5] setText:[self.listDescription objectAtIndex:indexPath.row]];
NSString *imagePath = [self.listLogo objectAtIndex:indexPath.row];
image.image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:imagePath]]];
return cell;
}
#end

Answer 1

The call
image.image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:imagePath]]];
will block the execution thread and being indeterminately long in terms of network use this is a bad thing. Each of your cells needs to wait to the image to load.
Check out "lazy loading of tableView cells" as a research topic.
Instead you should give the URL to the cell and tell it to load the image off the main thread.
as in
[cell loadImageAtURL:someURL];
and within a UITableViewCell subclass implementation
-(void)loadImageAtURL:(NSURL *)aurl
{
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
NSData *data = [NSData dataWithContentsOfURL:aurl];
if (data) {
UIImage *image = [UIImage imageWithData:data];
//must update UI on main queue
dispatch_async(dispatch_get_main_queue() ,^{
self.cellImageView = image;
}
}
});
}
Theres also a ton of Obj-C image loaders . EGOCache is my go to library but have a look round.
In summary the cell needs to own the image load process not the tableview because theres no guarantee that the cell will not be reused before the image loads and displays.

Answer 2

NSInteger is a primitive type, which means it can be stored locally on the stack. You don't need to use a pointer to access it. The way you are using it i think is a problem, getting the pointer value instead of the actual value of the primitive type.
I think this is what you want for the declaration/initialization of countPage:
NSInteger countPage = 1;