ios - 为什么从自定义 UIView 向 UIButton 添加 subview 不显示添加的 subview ？

Question

我有一个 UIView 的子类，我正在从一个 NIB 文件中加载它。我的 NIB 文件包含一个 UIButton 和一个 IBOutlet，称为 clock

@property (strong, nonatomic) IBOutlet UIButton *clock;

在我的界面生成器上我的时钟按钮中设置的文本显示出来了!但是我从 initWithCoder 添加的其他 subview 却没有。这是为什么？

.h文件

@interface TWTimerView : UIView

@property (strong, nonatomic) IBOutlet UIButton *clock;

@property (strong, nonatomic) UIImageView *circle;
@property (strong, nonatomic) UIImageView *pointer;
@property (strong, nonatomic) UIImageView *tick;

@property (strong, nonatomic) UIImageView *circleGlow;
@property (strong, nonatomic) UIImageView *pointerGlow;
@property (strong, nonatomic) UIImageView *tickGlow;

@end

.m 文件

@implementation TWTimerView

-(id)initWithCoder:(NSCoder *)aDecoder {

    self = [super initWithCoder:aDecoder];
    if(self) {

        self.backgroundColor = [UIColor clearColor];

        _circle  = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"circle"]];
        _pointer = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"pointer"]];
        _tick    = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"tick"]];

        [_clock addSubview:_circle];
        [_clock addSubview:_pointer];
        [_clock addSubview:_tick];

    }
    return self;
}

- (id)initWithFrame:(CGRect)frame
{

    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code
        TWTimerView *view= [[[NSBundle mainBundle] loadNibNamed:@"TimerView" owner:self options:nil] objectAtIndex:0];
        [self addSubview:view];

    }
    return self;
}

@end

谢谢!

Answer 1

这是我会做的:如果您不需要使用框架，请删除 initWithFrame 方法并使用另一种方法来帮助您加载 View ，如下所示。

+ (id)loadViewFromNIBFile {
    NSArray * array = [[NSBundle mainBundle] loadNibNamed:@"TimerView" owner:self options:nil];
    //You may want to assert array only contains one element here
    TWTimerView * view = (TWTimerView *)[array objectAtIndex:0];
    NSAssert([view isKindOfClass:TWTimerView.class], @"Unexpected class");
    [view _setDefaultComponents];
    return view;
}

- (void)_setDefaultComponents {
    self.backgroundColor = [UIColor clearColor];
    _circle  = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"circle"]];
    _pointer = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"pointer"]];
    _tick    = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"tick"]];
    [_clock addSubview:_circle];
    [_clock addSubview:_pointer];
    [_clock addSubview:_tick];
}

调用 [TWTimerView loadViewFromNIBFile] 获取您的 View 实例。