解析iOS中的JSON數據（Objective-c）並在TableView中顯示。獲取空值

Question

我在這裏經歷了類似的問題，但沒有找到我面臨的問題的答案。

我一直到現在都能夠解析JSON數據並存儲在字典中。這裏的JSON數據看起來像原始形式：

{"stores":[{"address":"7801 Citrus Park Town Center Mall","city":"Tampa","name":"Macy's","latitude":"28.068052","zipcode":"33625","storeLogoURL":"http://strong-earth-32.heroku.com/images/macys.jpeg","phone":"813-926-7300","longitude":"-82.573301","storeID":"1234","state":"FL"}, 

{"address":"27001 US Highway 19N","city":"Clearwater","name":"Dillards's","latitude":"27.9898988","zipcode":"33761","storeLogoURL":"http://strong-earth-32.heroku.com/images/Dillards.jpeg","phone":"727-296-2242","longitude":"-82.7294986","storeID":"1235","state":"FL"}, 

等..

正如你所看到的，它是字典的數組的字典。因此，我首先將原始數據存儲在字典中，將value提取爲key = stores並將其存儲在數組中。之後，我提取了每個字段並將其存儲在自定義對象tempStore中。這是失敗的時候。

- (void)viewDidLoad 
{ 
[super viewDidLoad]; 
[populatedStoreArray addObject:@"blah"]; 
NSString *jsonRawData = [[NSString alloc] initWithContentsOfURL:[NSURL URLWithString:@"http://strong-earth-32.heroku.com/stores.aspx"]]; 

if([jsonRawData length] == 0) 
{ 
    [jsonRawData release]; 
    return; 
} 
SBJsonParser * parser = [[SBJsonParser alloc]init]; 
resultData = [[parser objectWithString:jsonRawData error:nil]copy]; 
NSArray *storeArray = [[NSArray alloc]init]; 
storeArray= [resultData objectForKey:@"stores"]; 
Store *tempStore = [[Store alloc]init]; 

/*NSLog(@"show me stores: %@", storeArray);*/ 
for(int i=1;i<[storeArray count];i++) 
{ 
    NSDictionary *tempDictionary = [storeArray objectAtIndex:i]; 
    if([tempDictionary objectForKey:@"address"]!=nil) 
    { 
     tempStore.address= [tempDictionary objectForKey:@"address"]; 
     //NSLog(@"Address: %@",tempStore.address); 
    } 
    //and so on for other keys 
    [populatedStoreArray addObject:tempStore]; 
    NSLog(@"In array: %@",[populatedStoreArray objectAtIndex:i]); 
} 

這裏的tempStore對象：

- (id) init 
{ 
    if (self = [super init]) 
    { 
    self.address = @"address"; 
    self.city = @"city"; 
    self.name = @"name"; 
    self.latitude = @"latitude"; 
    self.longitude = @"longitude"; 
    self.state = @"state"; 
    self.phone = @"phone"; 
    self.storeid = @"storeID"; 
    self.url = @"storeLogoURL"; 
    self.zipcode = @"zipcode"; 
    } 
    return self; 
} 

現在，我使用populatedStoreArray用於填充表格的單元格。我不確定要顯示的格式，但我主要關心的是當我嘗試打印populatedStoreArray時，即使tempStore已填充，其內容仍然爲空。 我在這裏錯過了什麼？ 此外，populateStoreArray作爲屬性在.h文件中聲明。

@property (nonatomic, strong) NSMutableArray * populatedStoreArray; 

在此先感謝。

Answer 1

可可事項已經說上面你需要確保你的populatedStoreArray被alloc'ed和初始化，Objective-C的不當您嘗試將對象添加到nil數組時，出現錯誤，因此它看起來像添加它們，但不是。

另外我不知道它是否是你的實際代碼，但我注意到你只有alloc並初始化tempStore一次。所以你循環訪問數組並設置tempStore.address並每次添加同一個對象，所以你最終只能得到一個tempStore對象，你需要在每次迭代中分配並初始化一個新的tempStore對象你的循環：

Store *tempStore; 

/*NSLog(@"show me stores: %@", storeArray);*/ 
for(int i=1;i<[storeArray count];i++) 
{ 
    tempStore = = [[Store alloc]init]; 

    NSDictionary *tempDictionary = [storeArray objectAtIndex:i]; 
    if([tempDictionary objectForKey:@"address"]!=nil) 
    { 
     tempStore.address= [tempDictionary objectForKey:@"address"]; 
     //NSLog(@"Address: %@",tempStore.address); 
    } 
    //and so on for other keys 
    [populatedStoreArray addObject:tempStore]; 
    NSLog(@"In array: %@",[populatedStoreArray objectAtIndex:i]); 
} 

Answer 2

請先ALLOC您的NSMutableArray還綜合您的陣列的第一

像populatedStoreArray = [[NSMutableArray alloc] init];