ios--UIImage从网络下载、保存、显示图片

本是古典何须时尚 2022-08-10 14:56 187阅读 0赞

//从网络下载图片
    -(UIImage *) getImageFromURL:(NSString *)fileURL {
        NSLog(@"执行图片下载函数");
        UIImage * result;
         
        NSData * data = [NSData dataWithContentsOfURL:[NSURL URLWithString:fileURL]];
        result = [UIImage imageWithData:data];
         
        return result;
    }
     
    //将所下载的图片保存到本地
    -(void) saveImage:(UIImage *)image withFileName:(NSString *)imageName ofType:(NSString *)extension inDirectory:(NSString *)directoryPath {
        if ([[extension lowercaseString] isEqualToString:@"png"]) {
            [UIImagePNGRepresentation(image) writeToFile:[directoryPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.%@", imageName, @"png"]] options:NSAtomicWrite error:nil];
        } else if ([[extension lowercaseString] isEqualToString:@"jpg"] || [[extension lowercaseString] isEqualToString:@"jpeg"]) {
            [UIImageJPEGRepresentation(image, 1.0) writeToFile:[directoryPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.%@", imageName, @"jpg"]] options:NSAtomicWrite error:nil];
        } else {
            //ALog(@"Image Save Failed\nExtension: (%@) is not recognized, use (PNG/JPG)", extension);
            NSLog(@"文件后缀不认识");
        }
    }
     
    //读取本地保存的图片
    -(UIImage *) loadImage:(NSString *)fileName ofType:(NSString *)extension inDirectory:(NSString *)directoryPath {
        UIImage * result = [UIImage imageWithContentsOfFile:[NSString stringWithFormat:@"%@/%@.%@", directoryPath, fileName, extension]];
         
        return result;
    }
     
    //从网络下载图片，保存，并用 UIImageView 从保存中显示
    NSString * documentsDirectoryPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
        NSLog(@"保存路径:%@",documentsDirectoryPath);
        //Get Image From URL
        UIImage * imageFromURL = [self getImageFromURL:@"http://file.duteba.com/phone/2009/04/5/ftGxL8kcUL.jpg"];
         
        //Save Image to Directory
        [self saveImage:imageFromURL withFileName:@"MyImage" ofType:@"jpg" inDirectory:documentsDirectoryPath];
         
        //Load Image From Directory
        UIImage * imageFromWeb = [self loadImage:@"MyImage" ofType:@"jpg" inDirectory:documentsDirectoryPath];
        [img setImage:imageFromWeb];
         
        //取得目录下所有文件名
        NSArray *file = [[[NSFileManager alloc] init] subpathsAtPath:documentsDirectoryPath];
        //NSLog(@"%d",[file count]);
        NSLog(@"%@",file);