以下代码在调用 fetchAssetsWithOptions 时引发 NSInvalidArgumentException:
PHFetchOptions *allPhotosOptions = [[PHFetchOptions alloc] init];
allPhotosOptions.sortDescriptors =
@[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:NO]];
allPhotosOptions.predicate =
[NSPredicate predicateWithFormat:@"pixelHeight >= pixelWidth * 1.95" ];
self.allPhotos = [PHAsset fetchAssetsWithOptions:allPhotosOptions];
消息是
NSInvalidArgumentException ... reason: '*** -constantValue only defined for abstract class.
Define -[NSFunctionExpression constantValue]!'
我尝试了谓词格式字符串的多种变体,但当我尝试使用乘法时,总是会收到此消息。我究竟做错了什么?