如何将两个UIScrollView实例缩放到相同级别？

Question

我有两个UIScrollView实例,我想让它们同时缩放.

有没有经验呢？

我正在使用它NSNotificationCenter告诉我的对象何时缩放.最初我以为我可以以某种方式进入当前可见的矩形,并且只是打电话zoomToRect:,但我没有看到这样做的方法.我现在拥有的是设置zoomScale和contentOffset属性.它看起来像这样:

- (void)registerForZoomNotifications {
[[NSNotificationCenter defaultCenter] addObserver:self 
                                         selector:@selector(receiveZoomNotification:) 
                                             name:ZOOM_NOTIFICATION_IDENTIFIER 
                                           object:nil];
}

- (void)receiveZoomNotification:(NSNotification*)notification {

UIScrollView *currentScrollView = (UIScrollView*)[notification object];

// zoomLevel
[(UIScrollView*)self.view setZoomScale:currentScrollView.zoomScale animated:NO];

// contentOffset
[(UIScrollView*)self.view setContentOffset:currentScrollView.contentOffset animated:NO];
}

#pragma mark -
#pragma mark UIScrollViewDelegate

- (void)scrollViewDidZoom:(UIScrollView *)pageScrollView {

[[NSNotificationCenter defaultCenter] postNotificationName:ZOOM_NOTIFICATION_IDENTIFIER object:pageScrollView];

}

它不起作用,看起来非常不稳定.想法有人吗？我应该采取不同的方法吗？

编辑:我应该澄清两个滚动视图同时不可见.它们在完全相同的时间滚动并不重要,只有滚动视图与滚动完成后的另一个滚动视图处于相同的缩放级别(和可见的矩形).

Answer 1

更简单的方法是为您的UIView控件实现UIScrollViewDelegate协议,该协议管理2 UIScrollView2

在你的.h文件中只需添加@interface声明

@interface yourUIViewControll : UIViewControll <UIScrollViewDelegate> {
    UIScrollView *aUIScrollView;
    UIScrollView *bUIScrollView;
}

这样,现在你可以使用当用户滚动或缩放2 UIScrollView中的一个时所需的所有方法,例如,你想知道何时缩放或滚动,并且想让另一个进行缩放和滚动,你需要特别需要这些2

在.m:

// called when a UIScrollView is zooming:
    - (void)scrollViewDidZoom:(UIScrollView *)zoomViewInUse{
    // just to test in log window:
    // NSLog(@"changing zoom...  scrollViewInUse.zoomScale: %.5f", zoomViewInUse.zoomScale);
    //force both UIScrollViews to zoom at the new value
        aUIScrollView.zoomScale = zoomViewInUse.zoomScale;
        bUIScrollView.zoomScale = zoomViewInUse.zoomScale;
    }


// called when a UIScrollView is scrolling:
    - (void)scrollViewDidScroll:(UIScrollView *)scrollViewInUse{
       // just to test in log window:
       //  NSLog(@"scrollViewInUse..contentOffset.x:%.1f", scrollViewInUse.contentOffset.y);
       //force both UIScrollViews to scroll at the new value
        aUIScrollView.contentOffset = scrollViewInUse.contentOffset;
        bUIScrollView.contentOffset = scrollViewInUse.contentOffset;
    }