无法识别的选择器发送到实例defaultRepresentation iOS 8

Question

Below is my code which was working on previous version but in iOS 8 app gets crashed. Please help.

ALAsset *asset = self.mArrassets[indexPath.row];
//    NSURL *savedAssetUrl =asset.defaultRepresentation.url;
ALAssetRepresentation *representation = [asset defaultRepresentation];
NSURL *savedAssetUrl =[representation url];

Answer 1

That probably means that self.mArrassets has at least one object that is not ALAsset . NSArray may not determine what kind of an object stores. It must be reference type thats all.

The code below shows how to avoid such problems:

NSObject *asset = self.mArrassets[indexPath.row];
if ([asset isKindOfClass:[ALAsset class]]) {
//    NSURL *savedAssetUrl =asset.defaultRepresentation.url;
    ALAssetRepresentation *representation = [asset defaultRepresentation];
    NSURL *savedAssetUrl =[representation url];
}
else {
    NSLog(@" this is not ALAsset! The class is %@", [asset class]);
}