Objective-C變化的變量隨機值

Question

這真的是我的最後手段，因爲我絕對難倒，我只知道這是愚蠢的！

我有一個UITableView和一個UISearchBar，用戶使用搜索欄輸入一個位置，然後將該位置附加到page = 1的url。然後發送給api，並返回廣告列表（這已成功）。然後，用戶可以滾動到UITableView的底部並拉動以加載結果的下一頁（頁碼增加並且API再次被調用，也是成功的）。

如果我硬編碼到位置變量的地方「倫敦」的廣告加載儘可能多的網頁罰款，但是當我使用searchBar.text（這似乎是正確的），頁面1加載罰款，但頁面2崩潰/網址無效。當我輸出位置變量時，它不是一個字符串了，因此崩潰或者它是一些隨機數據。

我已經在網上大量搜索，沒有發現任何與一直停留在這2天，任何幫助，將不勝感激:)

我的代碼如下：

PropertySearchTableViewController.h

#import <UIKit/UIKit.h> 
#import <QuartzCore/QuartzCore.h> 

@interface PropertySearchTableViewController : UITableViewController <UISearchBarDelegate, UITableViewDelegate, UITableViewDataSource> { 

    IBOutlet UITableView *propertiesTableView; 
    UISearchBar *propertiesTableSearch; 
    NSMutableArray *propertiesArray; 

    NSString *location; 
} 

@property (nonatomic, retain) IBOutlet UISearchBar *propertiesTableSearch; 
@property (nonatomic, retain) NSMutableArray *propertiesArray; 
@property (nonatomic, retain) NSString *location; 

- (void)loadProperties; 
- (void)callback:(NSDictionary *)response; 

@end 

PropertySearchTableViewController.m

#import "PropertySearchTableViewController.h" 
#import "JSONHandler.h" 

@implementation PropertySearchTableViewController 
@synthesize location; 
@synthesize propertiesArray; 
@synthesize propertiesTableSearch; 

int page = 1; 

#pragma mark - 
#pragma mark View lifecycle 

- (void)viewDidLoad { 
    location = @"London"; 
    [self.propertiesTableSearch becomeFirstResponder]; 
    self.propertiesArray = [[NSMutableArray alloc] init]; 
    [self loadProperties]; 
    self.title = @"Properties"; 
} 

- (void)loadProperties { 
    NSLog(@"Calling: %@", ([location isKindOfClass:[NSString class]] ? location : @"No longer a string")); 
    NSString *url = [NSString stringWithFormat:@"http://local.somewebsite.co.uk/adverts/?where=%@&page=%i", location, page]; 
    JSONHandler *handler = [[JSONHandler alloc] initWithUrl:url andData:nil callbackObject:self]; 
    [handler handleConnection]; 
} 

- (void)callback:(NSDictionary *)response { 
    NSArray *properties = [response objectForKey:@"results"]; 
    NSEnumerator *enumerator = [properties objectEnumerator]; 
    NSDictionary* item; 
    while (item = (NSDictionary*)[enumerator nextObject]) { 
     NSDictionary *d = item; 
     [propertiesArray addObject:d]; 
    } 
    [self.tableView reloadData]; 
} 

#pragma mark - 
#pragma mark Table view data source 

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { 
    return 1; 
} 

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { 
    return [self.propertiesArray count]; 
} 

- (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]; 
    } 
    NSDictionary *d = [propertiesArray objectAtIndex:indexPath.row]; 
    cell.textLabel.text = [d objectForKey:@"ad_title"]; 
    return cell; 
} 

#pragma mark - 
#pragma mark Table view delegate 

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { 
} 

- (void)scrollViewDidScroll:(UIScrollView *)scrollView{ 
    CGPoint p = scrollView.contentOffset; 
    CGSize s = scrollView.contentSize; 
    CGSize scrollSize = scrollView.bounds.size; 
    if((p.y+scrollSize.height) > (s.height+50)){ 
     self.tableView.contentSize = CGSizeMake(0, s.height+50); 
     page++; 
     [self loadProperties]; 
    } 
} 

//Search 

- (void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar { 
    [searchBar setShowsCancelButton:YES animated:YES]; 
    self.tableView.scrollEnabled = NO; 
} 

- (void)searchBarCancelButtonClicked:(UISearchBar *)searchBar { 
    searchBar.text=@""; 
    [searchBar setShowsCancelButton:NO animated:YES]; 
    [searchBar resignFirstResponder]; 
    self.tableView.scrollEnabled = YES; 
} 

- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar { 
    location = (NSString *) searchBar.text; 
    page = 1; 
    NSLog(@"%@", searchBar.text); 
    [propertiesArray removeAllObjects]; 
    [self loadProperties]; 
    [self.tableView reloadData]; 
    [searchBar setShowsCancelButton:NO animated:YES]; 
    [searchBar resignFirstResponder]; 
    self.tableView.scrollEnabled = YES; 
} 

#pragma mark - 
#pragma mark Memory management 

- (void)didReceiveMemoryWarning { 
    // Releases the view if it doesn't have a superview. 
    [super didReceiveMemoryWarning]; 

    // Relinquish ownership any cached data, images, etc that aren't in use. 
} 

- (void)viewDidUnload { 
    // Relinquish ownership of anything that can be recreated in viewDidLoad or on demand. 
    // For example: self.myOutlet = nil; 
} 


- (void)dealloc { 
    [location release]; 
    [propertiesTableSearch release]; 
    [super dealloc]; 
} 


@end 

Answer 1

此行可能是罪魁禍首：

location = (NSString *) searchBar.text; 

您需要保留/複製字符串或將消失！

[location release]; //!< Release the last location string 
[location = [[searchBar text] copy]; //!< Get a copy of the new one