封装用于图片的放大与缩小的类BaseImgView——iOS学习连载34

本文详细介绍了如何在iOS应用中使用Swift语言通过添加点击事件来放大和缩小图片，并在.m文件中实现相应的手势交互功能。通过创建滑动视图、初始化子视图以及实现放大的动画效果，用户可以轻松地在应用中实现图片的动态缩放功能。

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//在.h文件中添加点击事件用来放大图片，并在.m文件进行实现

- (void)addTapEnlargeImgViewWithFullUrlStr:(NSString *)urlStr
{
    //开启点击事件
    self.userInteractionEnabled = YES;

    if(urlStr != nil)
    {
        fullImgUrl = urlStr;
    }

    //添加放大的手势
    enlargeTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(enlargeImgView:)];
    [self addGestureRecognizer:enlargeTap];
}

//初始化子视图
- (void)_initViews
{
    //创建滑动视图
    if(scrollView == nil)
    {
        scrollView = [[UIScrollView alloc] initWithFrame:[UIScreen mainScreen].bounds];
        scrollView.backgroundColor = [UIColor whiteColor];

        //在滑动视图上添加缩小的手势
        UITapGestureRecognizer *reduceTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(reduceImgView:)];
        [scrollView addGestureRecognizer:reduceTap];
    }
    [self.window addSubview:scrollView];

    //创建放大视图
    if(fullImageView == nil)
    {
        fullImageView = [[UIImageView alloc] initWithFrame:CGRectZero];
        fullImageView.image = self.image;
        fullImageView.contentMode = self.contentMode;
        [scrollView addSubview:fullImageView];
    }

//初始化进度条（需要导入第三方框架DDProgressView.h文件）

    if(progressView == nil)
    {
        progressView = [[DDProgressView alloc] initWithFrame:CGRectMake(10, (kScreenHeight - 10) / 2, kScreenWidth - 20, 10)];
        //设置样式
        progressView.outerColor = [UIColor orangeColor];
        progressView.innerColor = [UIColor grayColor];
        progressView.emptyColor = [UIColor cyanColor];
    }
    [self.window addSubview:progressView];
}

//放大图片的方法
- (void)enlargeImgView:(UITapGestureRecognizer *)tap
{
   if(self.image == nil)
   {
       return;
   }
    //初始化子视图

[self _initViews];

    //设置fullImageView的frame，获取该视图相对于另一个视图的frame
    CGRect rect = [self convertRect:rect toView:self.window];
    fullImageView.frame = rect;

    //刚开始隐藏进度条
    progressView.hidden = YES;

    //实现放大的动画

[UIView animateWithDuration:0.3 animations:^{

        CGFloat height = kScreenWidth / (self.image.size.width / self.image.size.height);
        fullImageView.frame = CGRectMake(0, 0, kScreenWidth, MAX(kScreenHeight, height));
        scrollView.contentSize = CGSizeMake(kScreenWidth, height);
    }
     completion:^(BOOL finished) {
         if(fullImgUrl == nil)
         {
             return;
         }
         [fullImageView sd_setImageWithURL:[NSURL URLWithString:fullImgUrl]placeholderImage:self.image options:SDWebImageRetryFailed progress:^(NSInteger receivedSize, NSInteger expectedSize) {
             progressView.hidden = NO;
             progressView.progress = (CGFloat)receivedSize / expectedSize;
         } completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType, NSURL *imageURL) {
             [progressView removeFromSuperview];
             progressView = nil;
         }];
     }];
}

//缩小图片的方法
- (void)reduceImgView:(UITapGestureRecognizer *)tap
{
    [progressView removeFromSuperview];
    progressView = nil;

    [UIView animateWithDuration:0.3 animations:^{

        //缩小图片的代理实现
        if([self.imgSizeDelegate respondsToSelector:@selector(imgReduce)])
        {
            [self.imgSizeDelegate imgReduce];
        }
        fullImageView.frame = [self convertRect:self.bounds toView:self.window];
    } completion:^(BOOL finished) {
        [fullImageView removeFromSuperview];
        fullImageView = nil;

        [scrollView removeFromSuperview];
        scrollView = nil;
    }];
}