相关疑难解决方法(0)

我试图创建一个静态变量来存储图像字典.不幸的是,我可以找到初始化它的最好方法是检入使用该变量的每个函数.由于我在一个类别中创建了这个变量,我不能只在初始化器中初始化它.有没有更简洁的初始化navigationBarImages的方法？

static NSMutableDictionary *navigationBarImages = NULL;

@implementation UINavigationBar(CustomImage)
//Overrider to draw a custom image
- (void)drawRect:(CGRect)rect
{
    if(navigationBarImages==NULL){
        navigationBarImages=[[NSMutableDictionary alloc] init];
    }
    NSString *imageName=[navigationBarImages objectForKey:self];
    if (imageName==nil) {
        imageName=@"header_bg.png";
    }
    UIImage *image = [UIImage imageNamed: imageName];
    [image drawInRect:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
}

//Allow the setting of an image for the navigation bar
- (void)setImage:(UIImage*)image
{
    if(navigationBarImages==NULL){
        navigationBarImages=[[NSMutableDictionary alloc] init];
    }
    [navigationBarImages setObject:image forKey:self];
}
@end