从 NSArray 对象设置 UIPickerView

Question

我正在尝试使用最近 20 个星期一的日期设置 UIPicker 视图。该数组填充了 20 个周对象。例如 NSDate *weekDate=3/24/2014 NSString *weekDateString=Week of 3/24/2014。

当我最初设置行时，它会正确显示前 5-6 行，当我尝试滚动选择器时，它会尝试为其显示的新行设置标题，但 setTitle 正在为 weekDateString 记录（null） .当我在 titleForRow 中记录计数时，列表仍显示计数为 20。

如果我将 NSArray 设置为 NSString 就没有问题。

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
        _weeks = [Week getWeeks];

    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.title=@"Weeks";
    [self.navigationController.navigationBar.layer insertSublayer:[LayoutColors getNavBarGradient:self.navigationController.navigationBar.bounds] atIndex:1];

    self.navigationController.navigationBar.titleTextAttributes
    = @{NSForegroundColorAttributeName : [UIColor whiteColor]};

    int startYValue = self.navigationController.navigationBar.frame.size.height + HeaderHeight;
    int width = self.view.frame.size.width;
    _picker = [[UIPickerView alloc] initWithFrame:CGRectMake(0, startYValue, width/2, DATE_PICKER_HEIGHT)];
    _picker.delegate = self;
    _picker.dataSource = self;

    [self.view addSubview:self.picker];
}

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
}
-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
    //One column
    return 1;
}

-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
    //set number of rows
    return _weeks.count;
}

-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    Week *week = [_weeks objectAtIndex:row];
    return week.weekDateString;
}

Answer 1

您的代码没有任何问题，因此不得不推断您的模型对象可能有问题，即您的 _weeks 数组实际上并没有按照您认为的方式正确填充 - @987654322 @ 显然缺少某些 Week 对象。你可能应该回去看看你是如何生成这个数组的。