iOS 实现点击微信头像效果
hc3lz2775
8年前
<p>公司产品需要实现点击个人主页头像可以放大头像、缩放头像、保存头像效果(和点击微信个人头像类似),故找个时间实现一下,记录下来,供自己查看,也给大家做个参考。</p> <p>实现效果(GIF):</p> <p style="text-align:center"><img src="https://simg.open-open.com/show/9cdf1ea93f87e96dc684fcad305bb8d1.gif"></p> <p>实现思路:</p> <p>直接自定义 UIView(CYPhotoPreviewer),为了实现双击缩放,可以实现 UIScrollViewDelegate 对应的方法。如果需要模糊背景,可以在自定义的 UIView 中先添加模糊背景,再添加 UIScrollView,继而在 UIScrollView 中添加图片容器,这个容器就是要显示的图片的 superView,代码一目了然:</p> <pre> <code class="language-objectivec">- (void)setup { self.frame = [UIScreenmainScreen].bounds; self.backgroundColor = [UIColorclearColor]; UITapGestureRecognizer *singleTap = [[UITapGestureRecognizeralloc] initWithTarget:selfaction:@selector(singleTap:)]; [self addGestureRecognizer:singleTap]; UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizeralloc] initWithTarget:selfaction:@selector(doubleTap:)]; doubleTap.numberOfTapsRequired = 2; [singleTaprequireGestureRecognizerToFail:doubleTap]; [self addGestureRecognizer:doubleTap]; UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizeralloc] initWithTarget:selfaction:@selector(longPress:)]; [self addGestureRecognizer:longPress]; // 设置模糊背景 self.blurBackground = [[UIVisualEffectViewalloc] initWithEffect:[UIBlurEffecteffectWithStyle:UIBlurEffectStyleExtraLight]]; self.blurBackground.frame = self.frame; [self addSubview:self.blurBackground]; // 设置 UIScrollView 相关属性 self.scrollView = [[UIScrollViewalloc] initWithFrame:[UIScreenmainScreen].bounds]; self.scrollView.delegate = self; self.scrollView.bouncesZoom = YES; self.scrollView.maximumZoomScale = 3.0; self.scrollView.multipleTouchEnabled = YES; self.scrollView.alwaysBounceVertical = NO; self.scrollView.showsVerticalScrollIndicator = NO; self.scrollView.showsHorizontalScrollIndicator = NO; [self addSubview:self.scrollView]; // containerView self.containerView = [[UIViewalloc] init]; [self.scrollViewaddSubview:self.containerView]; // imageView self.imageView = [[UIImageViewalloc] init]; self.imageView.clipsToBounds = YES; self.imageView.backgroundColor = [UIColorcolorWithWhite:1.0 alpha:0.5]; [self.containerViewaddSubview:self.imageView]; } </code></pre> <p>可以看到,我们给设置了模糊背景,给这个 CYPhotoPreviewer 添加了单击手势(关闭 PhotoPreviewer)、双击手势(缩放图片)、长按手势(使用 UIAlertController 菜单,比如保存图片等)。</p> <p>好,确定了这个 CYPhotoPreviewer 中的显示内容,那么我们该如何显示这个 CYPhotoPreviewer 呢?</p> <ul> <li>直接将这个 CYPhotoPreviewer 添加到 keyWindow 上</li> <li>将这个 CYPhotoPreviewer 添加到控制器的 self.view 上</li> </ul> <p>这两种方式的实现都差不多,不过如果使用第一种方式的话,会导致将 CYPhotoPreviewer 添加到 keyWindow 上之后,再长按继续将 UIAlertController 显示就比较麻烦了,因此,这里打算采用将 CYPhotoPreviewer 添加到控制器的 self.view 上,继而就可以很方便的显示 UIAlertController 了:</p> <pre> <code class="language-objectivec">- (void)previewFromImageView:(UIImageView *)fromImageViewinContainer:(UIView *)container { _fromImageView = fromImageView; fromImageView.hidden = YES; [containeraddSubview:self]; // 将 CYPhotoPreviewer 添加到 container 上 self.containerView.origin = CGPointZero; self.containerView.width = self.width; // containerView 的宽度是屏幕的宽度 UIImage *image = fromImageView.image; // 计算 containerView 的高度 if (image.size.height / image.size.height > self.height / self.width) { self.containerView.height = floor(image.size.height / (image.size.width / self.width)); } else { CGFloatheight = image.size.height / image.size.width * self.width; if (height self.height && self.containerView.height - self.height </code></pre> <p>可以看到,我们将外面的图片 fromImageView 传递进来,是为了显示更好的动画效果;将控制器的 container(self.view)传递进来,是为了将 CYPhotoPreviewer 添加到 container 的细节不需要在调用处处理,即初始化 CYPhotoPreviewer 之后,CYPhotoPreviewer 就直接被 container 添加为 subview 了。动画很简单不再细说。</p> <p>显示的效果已经做好,单击关闭 CYPhotoPreviewer 也比较好实现,只需要从父类移除 CYPhotoPreviewer 即可:</p> <pre> <code class="language-objectivec">- (void)dismiss { [UIViewanimateWithDuration:0.18 delay:0.0 options:UIViewAnimationOptionCurveEaseInOutanimations:^{ CGRectfromRect = [self.fromImageViewconvertRect:self.fromImageView.boundstoView:self.containerView]; self.imageView.contentMode = self.fromImageView.contentMode; self.imageView.frame = fromRect; self.blurBackground.alpha = 0.01; } completion:^(BOOL finished) { [UIViewanimateWithDuration:0.10 delay:0 options:UIViewAnimationOptionCurveEaseInOutanimations:^{ self.fromImageView.hidden = NO; self.alpha = 0; } completion:^(BOOL finished) { [self removeFromSuperview]; }]; }]; } </code></pre> <p>好了,显示和关闭 CYPhotoPreviewer 都实现了,如果需要双击缩放图片效果,就得实现 UIScrollViewDelegate 的两个方法以及 CYPhotoPreviewer 的双击手势:</p> <pre> <code class="language-objectivec">- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView{ return self.containerView; } - (void)scrollViewDidZoom:(UIScrollView *)scrollView { UIView *subView = self.containerView; CGFloatoffsetX = (scrollView.bounds.size.width > scrollView.contentSize.width)? (scrollView.bounds.size.width - scrollView.contentSize.width) * 0.5 : 0.0; CGFloatoffsetY = (scrollView.bounds.size.height > scrollView.contentSize.height)? (scrollView.bounds.size.height - scrollView.contentSize.height) * 0.5 : 0.0; subView.center = CGPointMake(scrollView.contentSize.width * 0.5 + offsetX, scrollView.contentSize.height * 0.5 + offsetY); } - (void)doubleTap:(UITapGestureRecognizer *)recognizer { if (self.scrollView.zoomScale > 1.0) { [self.scrollViewsetZoomScale:1.0 animated:YES]; } else { CGPointtouchPoint = [recognizerlocationInView:self.imageView]; CGFloatnewZoomScale = self.scrollView.maximumZoomScale; CGFloatxSize = self.width / newZoomScale; CGFloatySize = self.height / newZoomScale; [self.scrollViewzoomToRect:CGRectMake(touchPoint.x - xSize / 2, touchPoint.y - ySize / 2, xSize, ySize) animated:YES]; } } </code></pre> <p>最后一个就是长按弹出菜单(UIAlertController)了:</p> <pre> <code class="language-objectivec">- (void)longPress:(UILongPressGestureRecognizer *)recognizer { // 为了避免弹警告:Warning: Attempt to present on which is already presenting ,最好加入状态判断 if (recognizer.state == UIGestureRecognizerStateBegan) { UIAlertController *alertController = [UIAlertControlleralertControllerWithTitle:@"QuoraDots" message:nilpreferredStyle:UIAlertControllerStyleActionSheet]; [alertControlleraddAction:[UIAlertActionactionWithTitle:@"保存" style:UIAlertActionStyleDefaulthandler:nil]]; [alertControlleraddAction:[UIAlertActionactionWithTitle:@"取消" style:UIAlertActionStyleCancelhandler:nil]]; UIViewController *vc = self.viewController; [vcpresentViewController:alertControlleranimated:YEScompletion:nil]; } } </code></pre> <p>注意一点, longPress: 这个方法会调用很频繁,因此,为了避免 Attempt to present xxx on xxx which is already presenting xxx 这个警告,我们需要判断手势的状态。</p> <p>后话:</p> <p>这个只是显示单张图片的大图,如果需要显示多张图片类似微信微博的九宫格图片的大图显示,则需要将这个 CYPhotoPreviewer 搞成 UICollectionView 的 item 即可,大家可以尝试尝试。</p> <p> </p> <p> </p> <p> </p>