[NSNotificationCenter在应用程序终止并在iOS中再次启动时未触发

Question

我有一个银行应用程序，它要求禁用屏幕记录，并且我不希望人们使用新的iOS-11功能来记录带有敏感数据的屏幕并将其公开。由于无法在iOS中禁用屏幕录制，因此我尝试通过检测iOS11屏幕录制功能“开”或“关”来解决此问题。我使用了isCaptured和UIScreenCapturedDidChange Notification。代码如下：

   - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
  if (@available(iOS 11.0, *)) {
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(screenCaptureChanged) name:UIScreenCapturedDidChangeNotification object:nil];
    }

    return YES;
 }




-(void)screenCaptureChanged{

if (@available(iOS 11.0, *)) {

    BOOL isCaptured = [[UIScreen mainScreen] isCaptured];// will keep on checking for screen recorder if it is runnuning or not.

    if(isCaptured){

        UIView *colourView = [[UIView alloc]initWithFrame:self.window.frame];

        colourView.backgroundColor = [UIColor blackColor];

        colourView.tag = 1234;

        colourView.alpha = 0;

        [self.window makeKeyAndVisible];

        [self.window addSubview:colourView];

        // fade in the view

        [UIView animateWithDuration:0.5 animations:^{

            colourView.alpha = 1;

        }];

    }else{

        // grab a reference to our coloured view

        UIView *colourView = [self.window viewWithTag:1234];

        // fade away colour view from main view

        [UIView animateWithDuration:0.5 animations:^{

            colourView.alpha = 0;

        } completion:^(BOOL finished) {

            // remove when finished fading

            [colourView removeFromSuperview];

        }];

    }

} else {

    // Fallback on earlier versions

    // grab a reference to our coloured view

    UIView *colourView = [self.window viewWithTag:1234];

    if(colourView!=nil){

        // fade away colour view from main view

        [UIView animateWithDuration:0.5 animations:^{

            colourView.alpha = 0;

        } completion:^(BOOL finished) {

            // remove when finished fading

            [colourView removeFromSuperview];

        }];

    }

}
}

所以逻辑是在屏幕录制开始时触发通知，在录制发生时以及录制停止时将黑色置于视频上的逻辑被删除。当应用程序移至后台，活动，非活动和前景方案时，这可以很好地工作。但是，当应用程序被杀死（终止）而屏幕记录仍在进行时，而当我们再次启动应用程序而屏幕记录仍在进行时，黑色则无法覆盖屏幕。因此，如何在选择器方法正常工作的情况下再次调用通知选择器

我有一个银行应用程序，它要求禁用屏幕记录，并且我不希望人们使用新的iOS-11功能来记录带有敏感数据的屏幕并将其公开。 ...

Answer 1

使用iOS 13 SDK的场景