拍照后AVCapture暂停屏幕

Question

我使用了avcapture的演示示例，我想在viewcontroller中的imagview中显示图像后拍照我已经使用了代码

{
 ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];

[library enumerateGroupsWithTypes:ALAssetsGroupSavedPhotos usingBlock:^(ALAssetsGroup *group, BOOL *stop) {
    NSInteger numberOfAssets = [group numberOfAssets];
    if (numberOfAssets > 0) {
        NSInteger lastIndex = numberOfAssets-1;
        [group enumerateAssetsAtIndexes:[NSIndexSet indexSetWithIndex:lastIndex] options:0   usingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop) {
            UIImage *thumbnail = [UIImage imageWithCGImage:[result thumbnail]];
            if (thumbnail && thumbnail.size.width > 0) {
                imagviewlastimage.image = thumbnail;
                *stop = YES;
            }
        }];
    }
} failureBlock:^(NSError *error) {
    NSLog(@"error: %@", error);
}];

从照片库中获取最后一张图片，但我正在拍摄第二张图片

并在我在

中写入的选择图像后重定向viewController

captureManagerStillImageCaptured:(AVCamCaptureManager *)captureManager delegate

ViewController *temp=[[ViewController alloc]init];

temp.modalTransitionStyle = UIModalTransitionStyleCoverVertical;

[self presentModalViewController:temp animated:YES];

用作这个，如何解决这个问题？拍照后暂停屏幕