添加 IB 约束会破坏 UIPickerview - ObjC

Question

我有一个使用界面生成器构建的视图。每当我在现有 IB 视图之上添加 pickerview（通过 IB 或以编程方式）时，pickerview 将无法工作。选择器视图中的元素将无法正确滚动...旋转轮总是弹回“0 位置”&无法选择任何内容。此外，滚轮不再“发出咔哒声”...并且滚轮可以水平和垂直移动...但无法选择任何内容。

我什至尝试将 pickerview 添加到操作表中......结果相同。

如果我完全删除视图中的所有约束，则选取器视图将按其应有的方式工作。

关于造成此问题的原因和/或如何解决有什么想法吗？

屏幕拍摄

这是代码：

- (void)viewDidLoad {
    [super viewDidLoad];
    self.tabBarController.tabBar.hidden = YES;
    [self.view setBackgroundColor:[UIColor clearColor]];
    
letterArray = @[@"",@"A",@"B",@"C",@"D"];
    
    UIBarButtonItem *pBtn = [[UIBarButtonItem alloc] initWithTitle:@"picker"
                                                               style:UIBarButtonItemStylePlain
                                                              target:self
                                                                action:@selector(launchPicker:)];
    self.navigationItem.rightBarButtonItem = pBtn;
}

- (void)launchPicker:(id)sender {
    self.viewForMainPicker = [[UIView alloc]initWithFrame:CGRectMake(0, 400, [[UIScreen mainScreen] bounds].size.width, 220)];
    UIToolbar *toolBar = [[UIToolbar alloc]initWithFrame:CGRectMake(0, 0, [[UIScreen mainScreen] bounds].size.width, 44)];
    UIPickerview *mainPicker = [[UIPickerView alloc] initWithFrame:CGRectMake(0, 0, [[UIScreen mainScreen] bounds].size.width, 220)];
    
    UIFont *arrowfont = [UIFont boldSystemFontOfSize:40];
    UIFont *titlefont = [UIFont boldSystemFontOfSize:28];
    UIBarButtonItem *doneBtn = [[UIBarButtonItem alloc] initWithTitle:@"→"
                                                                style:UIBarButtonItemStylePlain
                                                               target:self
                                                               action:@selector(fakeEvent)];
    UIBarButtonItem *title = [[UIBarButtonItem alloc] initWithTitle:@"Select Gender"
                                                              style:UIBarButtonItemStylePlain
                                                             target:nil
                                                             action:nil];
    UIBarButtonItem *flex = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace
                                                                          target:self
                                                                          action:nil];
    [doneBtn setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
                                     [UIColor colorWithRed:0.933 green:0.122 blue:0.145 alpha:1.00], NSForegroundColorAttributeName,
                                     arrowfont, NSFontAttributeName, nil] forState:UIControlStateNormal];
    [title setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:
                                     [UIColor colorWithRed:0.933 green:0.122 blue:0.145 alpha:1.00], NSForegroundColorAttributeName,
                                     titlefont, NSFontAttributeName, nil] forState:UIControlStateNormal];
    NSArray *btnArray = [[NSArray alloc] initWithObjects:flex,flex,title,flex,doneBtn,nil];
    
    mainPicker.delegate = self;
    mainPicker.dataSource = self;
    
    [toolBar setItems:btnArray];
    [viewForMainPicker addSubview:mainPicker];
    [viewForMainPicker addSubview:toolBar];

    [self.view addSubview:viewForMainPicker];
}

- (void)fakeEvent {
    NSLog(@"selected");
}

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

- (NSInteger)pickerView:(nonnull UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
    return letterArray.count;
}

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

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    NSString *newString = [NSString stringWithFormat:@"%@", letterArray[row]];
    NSLog(@"passing: %@",newString);
}