封装保存、下载图片到本地的方法记录

//将图片保存到userDefaults
+ (void)SaveImageToLocal:(UIImage*)image Keys:(NSString*)key {
    NSUserDefaults* preferences = [NSUserDefaults standardUserDefaults];
    //[preferences persistentDomainForName:LocalPath];
    [preferences setObject:UIImagePNGRepresentation(image) forKey:key];
}

//将图片保存到沙箱目录
-(void)saveImage:(UIImage *)image toFilePath:(NSString *)filePath
{
    NSString *docDic=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES)[0];
    //这里自己起个名用于保存到目录的图片
    NSString *picPath=[docDic stringByAppendingPathComponent:@"你的图片名"];
    [UIImagePNGRepresentation(image) writeToFile:picPath atomically:YES];
}

//本地是否有相关图片
+ (BOOL)LocalHaveImage:(NSString*)key {
    NSUserDefaults* preferences = [NSUserDefaults standardUserDefaults];
    //[preferences persistentDomainForName:LocalPath];
    NSData* imageData = [preferences objectForKey:key];
    if (imageData) {
        return YES;
    }
    return NO;
}

//从本地获取图片
+ (UIImage*)GetImageFromLocal:(NSString*)key {
    NSUserDefaults* preferences = [NSUserDefaults standardUserDefaults];
    //[preferences persistentDomainForName:LocalPath];
    NSData* imageData = [preferences objectForKey:key];
    UIImage* image;
    if (imageData) {
        image = [UIImage imageWithData:imageData];
    }
    else {
        NSLog(@"未从本地获得图片");
    }
    return image;
}

//通过url下载图片
-(UIImage *)downloadImageFromURL:(NSURL *)url
{
    UIImage *img=[[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:url]];
    return img;
}