UIScreen上的snapshotViewAfterScreenUpdates在设备上显示空白快照

Question

我试图在用户看到它时获得整个屏幕的图像.以下代码应该可以工作,但它只能在模拟器中工作.我该怎么做才能让这个在运行iOS 8.1的设备上运行？

UIView *snapshot = [[UIScreen mainScreen] snapshotViewAfterScreenUpdates:YES];
CGSize outputSize = CGSizeMake([UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height);
UIGraphicsBeginImageContextWithOptions(outputSize, NO, 0);
[snapshot drawViewHierarchyInRect:CGRectMake(0.0, 0.0, outputSize.width, outputSize.height) afterScreenUpdates:YES];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

很高兴尝试其他策略,但关键是我想要它,因为用户看到它 - 键盘和所有.

干杯

Answer 1

UIGraphicsBeginImageContextWithOptions(CGSizeMake(CGRectGetWidth(self.view.frame), CGRectGetHeight(self.view.frame)), NO, 1.0f);
        [self.view drawViewHierarchyInRect:CGRectMake(0, 0, CGRectGetWidth(self.view.frame), CGRectGetHeight(self.view.frame)) afterScreenUpdates:NO];
        UIImage *snapshotImage = UIGraphicsGetImageFromCurrentImageContext();