This problem might be related to Instance variable not retaining value in iOS application.
My application has a table view that's supposed to be populated with data from a plist. The plist is question is determined based on a defaults setting.
After setting the contents of the instance variable, a count on it shows that it contains multiple records. However, if I then later try to count this instance variable when drawing the table view cells, it shows no records.
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I declared a "providerData" NSDictionary instance variable in my class header:
#import <UIKit/UIKit.h>
@interface ViewController : UITableViewController {
NSDictionary *providerData;
}
@property (nonatomic, retain) NSDictionary *providerData;
- (void)loadProviderDataSource:(NSString *)providerName;
@end
In my implementation I use viewDidLoad to read a dictionary from a plist file, check the value of "provider_preference", and then call [self loadProviderDataSource:providerPreference]:
- (void)viewDidLoad
{
[super viewDidLoad];
// Retrieve the user's provider preference from defaults:
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
// Set a default value for provider preference if the user didn't explicitly set one:
NSString *providerPreference = [[NSString alloc] initWithString:@"foo"];
if ([defaults stringForKey:@"provider_preference"]) {
providerPreference = [defaults stringForKey:@"provider_preference"];
}
// Load provider data from the relevant plist:
[self loadProviderDataSource:providerPreference];
}
This all works fine (using NSLog I can see that the plist file is read correctly and that a correct providerPreference value is passed to loadProviderDataSource.
The implementation for loadProviderDataSource is as follows:
- (void)loadProviderDataSource:(NSString *)providerName
{
// Set the filename and path for the data source:
NSString *dataSourceFileName = [[NSString alloc] initWithFormat:@"data-%@.plist",providerName];
NSString *dataSourcePath = [[NSBundle mainBundle] bundlePath];
dataSourcePath = [dataSourcePath stringByAppendingPathComponent:dataSourceFileName];
// Read the provider data:
self.providerData = [[NSDictionary alloc] initWithContentsOfFile:dataSourcePath];
NSLog(@"provider data entry count 1: %d", [self.providerData count]);
}
At this point the NSLog shows me that there are 2 entries in providerData.
However, when I have to set the cells for my table view, the NSLog in the following code shows me that providerData has 0 entries:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
NSLog(@"provider data entry count 2: %d", [self.providerData count]);
return cell;
}
In loadProviderDataSource I've tried using:
self.providerData = [[NSDictionary alloc] initWithContentsOfFile:dataSourcePath];
and:
[self setProviderData:[[NSDictionary alloc] initWithContentsOfFile:dataSourcePath]];
... neither work and I still end up with this in my log:
provider data entry count 1: 2
provider data entry count 2: 0
provider data entry count 2: 0
Any ideas?
