iphone - iOS 应用程序崩溃显示变量不是 CFArray

Question

我正在使用以下代码从 JSON 格式的 Web 服务中检索数据

NSString *responseString = [request responseString];
NSDictionary *responseDict = [responseString JSONValue];   
NSMutableDictionary *statusDict = [responseDict objectForKey:@"body"];
NSArray *arrayPickListValue = [statusDict objectForKey:@"ticketEntries"];

有时数据来自 arrayPickListValue 并在 iPhone 上显示内容，但有时如果 ticketEntries 键为 Null ，则显示变量不是 CFArray，那么我该如何解决这个问题

Answer 1

Try this:

 if([[statusDict objectForKey:@"ticketEntries"] isKindOfClass:[NSArray class]])
 {
    //is array
    NSArray *arrayPickListValue = [statusDict objectForKey:@"ticketEntries"];
 }
 else  
 {
    //not a array
    //manage here as it might is null.

 }

Answer 2

正如@Beppe 所说，您需要先检查一下：

// check whether it is NULL or not first
id arrayPickListValue = [statusDict objectForKey:@"ticketEntries"];
if ([arrayPickListValue isKindOfClass:[NSNull class]]) {
    // manage the error
    return;
}

// do work