如何在iOS应用中保存用户头像

Question

My app retrieve the image from a PHP json reply but how can i store the user avatar on my app? I always had to store the username in my previous work and i did that simply using the NSUserDefaults.
I read about NSCoding implementation but i didn't understand the complete flow, someone can explain that to me?

My goal is to have that image stored in order to show that quickly (i need to present that in every view) and not to load that every time from the server.

Thanks

Answer 1

Extend UIImageView (create a category) and use this code. Also use UIImageView+AFNetworking.

- (void)setDownloadedImage:(NSString *)imageName{
    NSString *libraryPath = [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES) lastObject];
    NSString *localImagePath = [libraryPath stringByAppendingPathComponent:imageName];

    // Check if the image is already downloaded
    if (![[NSFileManager defaultManager] fileExistsAtPath:localImagePath]) {
        // Store image
        NSURL *serverFilePath = [NSURL URLWithString:[NSString stringWithFormat:@"%@/images/avatars/%@", SERVER_URL, imageName]];
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
            NSData *imageData = [NSData dataWithContentsOfURL:serverFilePath];
            [imageData writeToFile:localImagePath atomically:YES];

            // Switch back to the main thread to update the UI
            dispatch_sync(dispatch_get_main_queue(), ^{
                [self setImageWithURL:[NSURL fileURLWithPath:localImagePath] placeholderImage:nil];
            });
        });
    }
    else{
        [self setImageWithURL:[NSURL fileURLWithPath:localImagePath] placeholderImage:nil];
    }
}

It checks if the image is already downloaded and if it is not it will be stored and read from disk. If it is already downloaded it will also read from disk.