Question

我从JSON Web服务获取此数据

List ARRAY: (
    {
    assets =         (
                    {
            identity = 34DL3611;
            systemId = 544507;
        },
                    {
            identity = 34GF0512;
            systemId = 5290211;
        },
                    {
            identity = 34HH1734;
            systemId = 111463609;
        },
                    {
            identity = 34HH1736;
            systemId = 111463622;
        },
                    {
            identity = 34YCJ15;
            systemId = 294151155;
        }
    );
    identity = DEMO;
    systemId = 4921244;
})

使用此代码：

NSArray *list =[NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];

NSLog(@"Response data: %@", responseString);

NSLog(@"List ARRAY: %@", list);

NSDictionary *dict = [list objectAtIndex: 0];

NSMutableArray *vehicleGroups = [dict objectForKey:@"identity"];

NSLog(@"Vehicle Groups: %@", vehicleGroups);

以下是我正在使用的选择器代码：

    -(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
return 1;}

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent :(NSInteger)component { 
return [vehicleGroups count];}

-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{return nil;}

-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{
 }

应用程序在

行崩溃

return [vehicleGroups count];

numberOfRowsInComponent的委托方法pickerView。我没有得到 - 我为什么要面对这个问题？

//代码////

    NSArray *list =[NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];

NSLog(@"Response data: %@", responseString);

NSLog(@"List ARRAY: %@", list);

NSDictionary *dict = [list objectAtIndex: 0];

vehicleList = [dict objectForKey: @"assets"];

self.vehicleGroups = [[NSMutableArray alloc] init];

vehicleGroups = [dict objectForKey:@"identity"];

NSLog(@"Vehicle Groups: %@", vehicleGroups);

NSString *identity = [dict objectForKey: @"identity"];

NSString *systemid = [dict objectForKey:@"systemId"];

self.listVehicles = [[NSMutableArray alloc] init];

self.listVehiclesID =[[NSMutableArray alloc]init];

NSLog(@"GroupOfVehicles: %@", groupOfVehicles);

for (NSUInteger index = 0; index < [vehicleList count]; index++) {

    itemDict = [vehicleList objectAtIndex: index];

    [self.listVehicles addObject:[itemDict objectForKey:@"identity"]];

    [self.listVehiclesID addObject:[itemDict objectForKey:@"systemId"]];
}

NSLog(@"Group Name: %@", identity);

NSLog(@"Assets: %@", listVehicles);

NSLog(@"Assets System ID: %@", listVehiclesID);

NSLog(@"GroupSystemID: %@", systemid);

Answer 1

您必须首先初始化数组

NSDict *list =[NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];

NSLog(@"List Dict: %@", list);

NSMutableArray *temp = list[@"assets"];
NSMutableArray *vehicleGroups = [NSMutableArry array];
vehicleGroups = temp[0][@"identity"];

NSLog(@"Vehicle Groups: %@", vehicleGroups);

Answer 2

如果他们遇到同样的问题，回答我自己的问题就会引导他人。实际上我在这里做的是获得所需的身份数组：DEMO如下：

vehicleGroups =[NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];

NSLog(@"Response data: %@", responseString);

NSLog(@"List ARRAY: %@", vehicleGroups);

NSDictionary *dict1 = [vehicleGroups objectAtIndex: 0];

NSString *identity1 = [dict objectForKey: @"identity"];

NSLog(@"dictNEW: %@", dict1);

groupOfVehicles = [[NSMutableArray alloc] init];
for (NSUInteger index = 0; index < [vehicleGroups count]; index++) {

    itemDict = [vehicleGroups objectAtIndex: index];

    [groupOfVehicles addObject:[itemDict objectForKey:@"identity"]];
}

NSLog(@"Group Name NEW: %@", identity1);

NSLog(@"Groups NEW: %@", groupOfVehicles);

使用该代码后，我已正确获取所需数据的数组

Answer 3

将数组保留为

在[vehicleGroups retain]

之后

vehicleGroups = [dict objectForKey:@"identity"];

Answer 4

NSDictionary *dicts = [list objectAtIndex: 0];
NSMutableArray *vehicleGroups = [[NSMutableArray  alloc] init];
for (NSDictionary *dict in dicts) 
{
    NSString* identity = [dict objectForKey:@"identity"];
    [vehicleGroups addObject:identity];
}
NSLog("count is %d",[vehicleGroups count]);

试一试：）

Answer 5

您的JSON数据不是JSON。

{
    "assets" : [
        {
            "identity" : "34DL3611",
            "systemId" : 544507
        },
        ....
        {
            "identity" = "34YCJ15",
            "systemId" = 294151155
        }
    ],
   "identity" = "DEMO",
   "systemId" = 4921244
}

这是您在JSON中描述的数据的一个可能示例。

Answer 6

NSDictionary *dict = [list objectAtIndex: 0];

NSMutableArray *vehicleGroups = [dict objectForKey:@"identity"];

在我看来，dict这里有一个包含三个条目的字典：assets，identity和systemId。在这个级别，identity的值只是一个字符串，“DEMO”，但是你试图将它分配给一个可变数组。我想你想要这样的东西：

NSDictionary *dict = [list objectAtIndex: 0];
NSArray *assets = [dict objectForKey:@"assets"];
NSArray *vehicleGroups = [assets objectForKey:@"identity"];

（将-objectForKey:发送到数组是可以的 - 您将获得与接收器中每个对象的给定键对应的对象数组。）

用于选择器视图iPhone的JSON数组

6 个答案: