iOS中广告SDK如何判断一个广告是否真实展示

在 iOS 中，广告 SDK 判断广告真实展示主要通过以下几种方式：

1. 基于视图可见性的检测

可视区域检测

objective-c

// 检查广告视图是否在屏幕可见区域内
CGRect screenRect = [UIScreen mainScreen].bounds;
CGRect adRect = [adView convertRect:adView.bounds toView:nil];
BOOL isVisible = CGRectIntersectsRect(screenRect, adRect);

// 检查视图是否被其他视图遮挡
BOOL isNotCovered = (adView.superview != nil && 
                     !adView.hidden && 
                     adView.alpha > 0.1);

视图层级检查

objective-c

- (BOOL)isViewVisible:(UIView *)view {
    // 检查视图及其父视图是否可见
    UIViewController *rootVC = [UIApplication sharedApplication].keyWindow.rootViewController;
    UIView *currentView = view;
    
    while (currentView != nil) {
        if (currentView.hidden || currentView.alpha < 0.01) {
            return NO;
        }
        currentView = currentView.superview;
    }
    
    return YES;
}

2. 展示时间要求

大多数广告 SDK 要求广告必须：

• 持续展示：通常需要连续展示 1-2 秒

• 足够的像素比例：通常要求 50% 以上的广告像素可见

• 处于活跃状态：应用在前台运行

objective-c

// 计时器检测持续展示时间
__block NSTimeInterval startTime = 0;
__block BOOL hasTracked = NO;

- (void)checkAdDisplayDuration {
    if ([self isAdViewVisible] && !hasTracked) {
        if (startTime == 0) {
            startTime = [[NSDate date] timeIntervalSince1970];
        } else {
            NSTimeInterval currentTime = [[NSDate date] timeIntervalSince1970];
            if (currentTime - startTime >= 1.0) { // 至少1秒
                [self trackImpression];
                hasTracked = YES;
            }
        }
    } else {
        startTime = 0;
    }
}

3. 像素面积计算

objective-c

- (CGFloat)calculateVisiblePercentage {
    CGRect screenBounds = [UIScreen mainScreen].bounds;
    CGRect adFrameInScreen = [adView convertRect:adView.bounds toView:nil];
    
    // 计算交集矩形
    CGRect intersectionRect = CGRectIntersection(screenBounds, adFrameInScreen);
    
    if (CGRectIsNull(intersectionRect)) {
        return 0.0;
    }
    
    CGFloat adArea = adView.bounds.size.width * adView.bounds.size.height;
    CGFloat visibleArea = intersectionRect.size.width * intersectionRect.size.height;
    
    return (adArea > 0) ? (visibleArea / adArea) : 0.0;
}

4. 主流广告 SDK 的实现

Google AdMob

objective-c

// AdMob 自动处理展示检测
GADBannerView *bannerView = [[GADBannerView alloc] init];
bannerView.adUnitID = @"your-ad-unit-id";
bannerView.rootViewController = self;

// 通过 delegate 接收展示回调
- (void)adViewDidReceiveAd:(GADBannerView *)bannerView {
    // 广告成功展示时会调用此方法
}

Facebook Audience Network

objective-c

FBAdView *adView = [[FBAdView alloc] initWithPlacementID:@"your-placement-id"
                                                  adSize:kFBAdSizeHeight50Banner
                                      rootViewController:self];

// 展示回调
- (void)adView:(FBAdView *)adView didLoadWithError:(NSError *)error {
    if (!error) {
        // 广告准备展示
    }
}

5. 自定义展示检测

objective-c

@interface AdDisplayTracker : NSObject
@property (nonatomic, weak) UIView *adView;
@property (nonatomic, strong) NSTimer *displayTimer;
@property (nonatomic, assign) BOOL impressionTracked;
@end

@implementation AdDisplayTracker

- (void)startTracking {
    self.displayTimer = [NSTimer scheduledTimerWithTimeInterval:0.1
                                                        target:self
                                                      selector:@selector(checkDisplay)
                                                      userInfo:nil
                                                       repeats:YES];
}

- (void)checkDisplay {
    if (self.impressionTracked) return;
    
    BOOL isVisible = [self isViewVisible:self.adView];
    CGFloat visiblePercentage = [self calculateVisiblePercentage];
    
    if (isVisible && visiblePercentage >= 0.5) {
        [self trackImpressionIfNeeded];
    }
}

- (void)trackImpressionIfNeeded {
    // 确保只跟踪一次展示
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        [self sendImpressionTracking];
        self.impressionTracked = YES;
    });
}

6. 注意事项

1. 避免重复计数：确保每个广告只记录一次展示

2. 考虑设备方向：横竖屏切换时重新计算可见区域

3. 性能优化：检测频率不宜过高，避免影响应用性能

4. 遵守平台政策：按照各广告平台的展示定义标准实现

这些方法组合使用可以比较准确地判断广告是否真实展示，符合行业标准的展示定义。