IOS 判断相册是否允许访问

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

    [library writeImageToSavedPhotosAlbum:p_w_picpath.CGImage orientation:p_w_picpath.p_w_picpathOrientation completionBlock:^(NSURL *asSetUrl,NSError *error){  

        if (error) {  

            UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"保存图片失败"  

                                                           message:@"请打开 设置-隐私-照片 来进行设置"  

                                                          delegate:nil  

                                                 cancelButtonTitle:@"确定"  

                                                 otherButtonTitles:nil, nil];  

            [alert show];  

            [alert release];  

        }else{  

            UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"保存图片成功"  

                                                           message:nil  

                                                          delegate:nil  

                                                 cancelButtonTitle:@"确定"  

                                                 otherButtonTitles:nil, nil];  

            [alert show];  

            [alert release];  

        }  

    }];