ios - 创建对象的 NSMutableArray

Question

我在向 NSMutableArray 添加对象时遇到问题。我明明在 typeList 数组中放置了 2 个对象，但计数只显示为 1。我做错了什么？

内容.h

@interface TBContentModel : NSObject

+(NSMutableArray*)typeList;
+(void)setTypeList:(NSMutableArray*)str; 

内容.m

static NSMutableArray *typeList = nil;

@implementation TBContentModel

- (id) init {
    self = [super init];
    if (self) {
        typeList = [NSMutableArray array];
    }
    return self;
}

contentviewcontroller.m

@implementation TBViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    NSString *jsonString = @"[{\"Content\":268,\"type\":\"text\"},{\"Content\":65,\"type\":\"number\"}]";
    NSData *data = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
    NSMutableArray *array = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil];
    for (NSMutableDictionary *dictionary in array)
    {
        TBContentModel *test = [[TBContentModel alloc] init];
        test.type = dictionary[@"type"];
        [[TBContentModel typeList] addObject:test];
        NSLog(@"%@", test.type);
    }
}

- (IBAction)tapButton:(id)sender {
     NSLog(@"%d", [TBContentModel.typeList count]); // always shows 1
}

Answer 1

每次分配和初始化新的 TBContentModel 对象时，您都在重新创建静态 typeList 对象。

进行以下更改:

static NSMutableArray *typeList = nil;
static dispatch_once_t once;

+ (NSMutableArray*)typeList {
    dispatch_once(&once, ^{
        typeList = [NSMutableArray array];
    });
    return typeList;
}

并从 init 方法中删除以下行:

typeList = [NSMutableArray array];