ios - 实现 UIPopoverBackgroundView 子类时出现乱码异常

Question

我已经按如下方式实现了这个类:

#import "JKBackgroundView.h"

@implementation JKBackgroundView

static CGFloat jkArrowBase = 26.0;
static CGFloat jkArrowHeight = 16.0;

// Background image insets
static CGFloat jkBackgroundTopInset = 68.0f;
static CGFloat jkBackgroundLeftInset = 16.0f;
static CGFloat jkBackgroundBottomInset = 16.0f;
static CGFloat jkBackgroundRightInset = 34.0f;

// Content view insets
static CGFloat jkContentTopInset = 40.0f;
static CGFloat jkContentLeftInset = 6.0f;
static CGFloat jkContentBottomInset = 8.0f;
static CGFloat jkContentRightInset = 7.0f;

+(CGFloat)arrowBase {
    return jkArrowBase;
}

-(UIPopoverArrowDirection)arrowDirection {
    return UIPopoverArrowDirectionUp;
}

-(CGFloat)arrowOffset {
    return 0.0f;
}

+(CGFloat)arrowHeight {
    return jkArrowHeight;
}

+(UIEdgeInsets)contentViewInsets {
    return UIEdgeInsetsMake(jkContentTopInset, jkContentLeftInset, jkContentBottomInset, jkContentRightInset);
}

-(void)drawRect:(CGRect)rect {
    UIEdgeInsets popoverInsets = UIEdgeInsetsMake(jkBackgroundTopInset, jkBackgroundLeftInset, jkBackgroundBottomInset, jkBackgroundRightInset);
    UIImage *popoverImage = [[UIImage imageNamed:@"popover_stretchable.png"] resizableImageWithCapInsets:popoverInsets];
    [popoverImage drawInRect:rect];
}

-(id)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        self.backgroundColor = [UIColor clearColor];
    }
    return self;
}

-(void)setArrowDirection:(UIPopoverArrowDirection)arrowDirection {
    // Do nothing
}

@end

我使用以下代码将它添加到我的 UIPopoverView(不是子类):

_logoutPopover.popoverBackgroundViewClass = [JKBackgroundView class];

但是，当我运行该项目时，我收到了一条疯狂的错误消息，如下所示:

* Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '-[UIPopoverBackgroundView º¯lå] must be implemented by subclassers.'

有谁知道它认为我没有实现什么方法？它似乎只是一堆胡言乱语。谢谢!

编辑 看来我忘了实现 setArrowOffset:。添加后它起作用了。 Apple 的错误消息只是乱码。

Answer 1

根据docs for UIPopoverBackgroundView您还需要为 UIPopoverBackgroundView 中的属性实现 setter(即 arrowDirection 和 arrowOffset。)您刚刚在实现中获得了 getter .