解析 JSON 顯示 nil 值

Question

SBJsonParser *parser = [[SBJsonParser alloc] init];
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://www.krsconnect.no/community/api.html?method=bareListEventsByCategory&appid=620&category-selected=350&counties-selected=Vest-Agder,Aust-Agder"]];
NSData *response = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
NSString *json_string = [[NSString alloc] initWithData:response encoding:NSUTF8StringEncoding];
NSDictionary *object = [parser objectWithString:json_string error:nil];
//appDelegate.books = [[NSMutableArray alloc] initWithCapacity:0];
appDelegate.books1 = [[NSMutableArray alloc] init];

NSArray *results = [parser objectWithString:json_string error:nil];
for (int i=0; i<[results count]; i++) {
    Book1  *aBook = [[Book1 alloc] initWithDictionary:[results objectAtIndex:i]];
    [appDelegate.books1 addObject:aBook];
    Book1 *mybook=[appDelegate.books1 objectAtIndex:i];
    NSString*test=mybook.location;
    NSLog(test);
}

字典解析

- (id)initWithDictionary:(NSDictionary*) dict {

    self.date = [dict valueForKey:@"date"];
    self.location =  [dict valueForKey:@"location"];
    self.municipality = [dict valueForKey:@"municipality"];
    self.title =  [dict valueForKey:@"title"];

    return self;
}

Answer 1

NSDictionary *object = [parser objectWithString:json_string error:nil]; 
.. 
NSArray *results = [parser objectWithString:json_string error:nil];

這一次，您可能需要決定要解析的數據應該是 NSArray 還是 NSDictionary（見上文：您將相同的字符串分配給它們中的任何一個）。

一般來說：您的數據錯誤（很可能格式不正確），這是 SBJson 返回 nil 的最可能原因，但是，將 NSError 傳遞給錯誤參數可能會給您提供真正的原因（這就是錯誤處理的真正用途）