ios将base64字符串转为图片，点击图片全屏展示

UIImageView *imageView=[[UIImageView alloc] initWithFrame:CGRectMake(20, 10, Screen_width-40, 180)];

        // 将base64字符串转为NSData

        NSData *decodeData = [[NSData alloc]initWithBase64EncodedString:[orderInfoDic objectForKey:@"IMAGEURL"] options:(NSDataBase64DecodingIgnoreUnknownCharacters)];

        // 将NSData转为UIImage

        UIImage *decodedImage = [UIImage imageWithData: decodeData];

        imageView.userInteractionEnabled = YES;

        [imageView setImage:decodedImage];

        UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(showZoomImageView:)];

        tapGesture.numberOfTapsRequired=1;

        [imageView addGestureRecognizer:tapGesture];

        [cell.contentView addSubview:imageView];

        return cell;

//放大缩小图片

-(void)showZoomImageView:(UITapGestureRecognizer *)tap

{

    if (![(UIImageView *)tap.view image]) {

        return;

    }

    UIView *bgView = [[UIView alloc] init];

    bgView.frame = [UIScreen mainScreen].bounds;

    bgView.backgroundColor = [UIColor blackColor];

    [[[UIApplication sharedApplication] keyWindow] addSubview:bgView];

    UITapGestureRecognizer *tapBgView = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapBgView:)];

    [bgView addGestureRecognizer:tapBgView];

    //必不可少的一步，如果直接把点击获取的imageView拿来玩的话，返回的时候，原图片就完蛋了

    UIImageView *tempImageView = (UIImageView*)tap.view;

    UIImageView *imageView = [[UIImageView alloc] initWithFrame:tempImageView.frame];

    imageView.image = tempImageView.image;

    [bgView addSubview:imageView];

    [UIView animateWithDuration:0.5 animations:^{

        CGRect frame = imageView.frame;

        frame.size.width = bgView.frame.size.width;

        frame.size.height = frame.size.width * (imageView.image.size.height / imageView.image.size.width);

        frame.origin.x = 0;

        frame.origin.y = (bgView.frame.size.height - frame.size.height) * 0.5;

        imageView.frame = frame;

    }];

}

-(void)tapBgView:(UITapGestureRecognizer *)tapBgRecognizer

{

    [tapBgRecognizer.view removeFromSuperview];

}