ios – 当iPad应用程序进入后台时关闭popover

基本上类别swizzles initWithContentViewController：因此它可以跟踪NSHashTable中的实时UIPopoverController实例(它本身不会保持包含的UIPopoverControllers,因为它保持对它们的弱引用.)它还监视UIApplicationDidEnterBackgroundNotification,当它到达时它会迭代收集现场UIPopoverControllers并解散任何正在显示的内容.

可能很高兴将其扩展到实现Apple所拥有的“永不允许两个popovers立即显示”规则.

我不是生产应用程序中混乱方法的忠实粉丝,但这看起来非常安全.

没有特别的使用说明.只需在项目中包含该类别,即可正常使用UIPopoverControllers.

#import <objc/runtime.h>

@interface UIPopoverController (autodismiss)
@end

@implementation UIPopoverController (autodismiss)

static NSHashTable* ts_popoverHashTable;

+ (void) load
{
    SEL originalSelector = @selector(initWithContentViewController:);
    SEL replacementSelector = @selector(ts_initWithContentViewController:);
    Method originalMethod = class_getInstanceMethod( [UIPopoverController class],originalSelector);
    Method replacementMethod = class_getInstanceMethod( [UIPopoverController class],replacementSelector);
    method_exchangeImplementations(originalMethod,replacementMethod);

    [[NSNotificationCenter defaultCenter] addobserver: self
                                             selector: @selector( applicationDidEnterBackgroundNotification: )
                                                 name: UIApplicationDidEnterBackgroundNotification
                                               object: nil];
}

- (id) ts_initWithContentViewController: (UIViewController*) contentViewController
{
    UIPopoverController* pc = [self ts_initWithContentViewController: contentViewController];

    static dispatch_once_t oncetoken;
    dispatch_once(&oncetoken,^{

        ts_popoverHashTable = [NSHashTable weakObjectsHashTable];
    });

    [ts_popoverHashTable addobject: pc];

    return pc;
}

+ (void) applicationDidEnterBackgroundNotification: (NSNotification*) n
{
    for ( UIPopoverController* pc in ts_popoverHashTable )
    {
        if ( pc.isPopoverVisible )
        {
            [pc dismisspopoverAnimated: NO];
        }
    }
}

@end