https://my.oschina.net/iq19900204/blog/206816
@interface HYShowImageView : UIScrollView <UIScrollViewDelegate>
//显示图像大图
-(void)showImage:(UIImage*)image inView:(UIView *)parentsView fromRect:(CGRect)rect;
@end
先看一下头文件，继承UIScrollView，实现UIScrollViewDelegate协议。
提供了一个方法ShowImage。
接下来看看这个方法是实现
-(void)showImage:(UIImage*)image inView:(UIView *)parentsView fromRect:(CGRect)rect
{
_oldRect = rect;
[self setFrame:CGRectMake(0, 0, PHOTOWIDTH, PHOTOHEIGHT)];
self.showsHorizontalScrollIndicator = NO;
self.showsVerticalScrollIndicator = NO;
UIImageView *showView = [[UIImageView alloc] initWithFrame:_oldRect];
showView.contentMode = UIViewContentModeScaleAspectFit;
[UIView animateWithDuration:0.5f animations:^{
[showView setFrame:CGRectMake(0, 0, PHOTOWIDTH, PHOTOHEIGHT)];
}];
[self setBackgroundColor:color_with_rgba(0, 0, 0, 1)];
[parentsView addSubview:self];
[showView setTag:'show'];
[showView setImage:image]; //这个地方也可以用网络的图片
[self addSubview:showView];
//增加两个手势
showView.userInteractionEnabled = YES;
UITapGestureRecognizer* singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleSingleViewTap:)];
[self addGestureRecognizer:singleTap];
UIPinchGestureRecognizer* pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(handlePinchView:)];
[self addGestureRecognizer:pinchGesture];
}
增加了两个手势，一个点击取消，一个缩放
//移除图片查看视图
-(void)handleSingleViewTap:(UITapGestureRecognizer *)sender
{
[self setZoomScale:1.0 animated:NO];
[UIView animateWithDuration:0.5f animations:^{
UIImageView *showView = (UIImageView *)[self viewWithTag:'show'];
showView.frame = _oldRect;
self.backgroundColor = color_with_rgba(0, 0, 0, 0.0);
} completion:^(BOOL finished){
[self removeFromSuperview];
}];
}
//缩放图片
-(void)handlePinchView:(UIPinchGestureRecognizer *)sender
{
UIImageView *imageView = (UIImageView *)[self viewWithTag:'show'];
if ([sender state] == UIGestureRecognizerStateBegan) {
_imageHWScale = imageView.image.size.height/imageView.image.size.width;
_beganScale = self.zoomScale;
}
[self setZoomScale:_beganScale * sender.scale];
if ([sender state] == UIGestureRecognizerStateEnded) {
[self scrollViewEnd];
}
}
- (void)scrollViewEnd
{
if (self.zoomScale < 1.0) {
[self setZoomScale:1.0 animated:YES];
self.contentOffset = CGPointMake(0, 0);
} else if (self.zoomScale > 3.0) {
[self setZoomScale:3.0 animated:YES];
}
}
实现委托的方法：
pragma mark - ScrollView delegate
-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
for (UIView *v in scrollView.subviews){
return v;
}
return nil;
}
(void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(CGFloat)scale
{
[self scrollViewEnd];
}·(void)scrollViewDidZoom:(UIScrollView *)scrollView
{
UIImageView *imageView = (UIImageView *)[self viewWithTag:'show'];
_imageHWScale = imageView.image.size.height/imageView.image.size.width;
if (self.contentOffset.x<=0 && self.contentOffset.y<=0) {
self.contentOffset = CGPointMake((imageView.width - PHOTOWIDTH)/2, (imageView.width - PHOTOWIDTH));
}
}
总结：
优点：这种缩放方式是使用了ScrollView自带的zoom缩放，所有使用简单
缺点：这种缩放方式如果图片高度不符合屏幕的话，放大后上下会有很大的空白部分（待解决）
推荐使用库：MJPhotoBrowse:http://code4app.com/ios/快速集成图片浏览器/525e06116803fa7b0a000001
原版本有一些问题，我修改了bug到了这里:http://git.oschina.net/jonear/MJPhotoBrowser
