iOS中UIScrollView嵌套UITableView的实践教程

#pragma mark - 底部的scrollViuew的代理方法scrollViewDidScroll

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
 CGFloat placeholderOffset = 0;
 if (self.topView.getSelectedItemIndex == 0) {
  if (self.firstTableView.contentOffset.y > self.topView.height - kItemheight) {
   placeholderOffset = self.topView.height - kItemheight;
  }
  else {
   placeholderOffset = self.firstTableView.contentOffset.y;
  }
  [self.secondTableView setContentOffset:CGPointMake(0, placeholderOffset) animated:NO];
 }
 else {
  if (self.secondTableView.contentOffset.y > self.topView.height - kItemheight) {
   placeholderOffset = self.topView.height - kItemheight;
  }
  else {
   placeholderOffset = self.secondTableView.contentOffset.y;
  }
  [self.firstTableView setContentOffset:CGPointMake(0, placeholderOffset) animated:NO];
 }
}

#pragma mark - 底部的scrollViuew的代理方法scrollViewDidEndDecelerating

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{ 
 NSInteger index = ceilf(scrollView.contentOffset.x / kScreen_Width);
 self.topView.selectedItemIndex = index;
}

#pragma mark - 重载系统的hitTest方法

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
 ViewController *currentVC = (ViewController *)self.nextResponder;
 currentVC.printPoint = point;
 if ([self.topView pointInside:point withEvent:event]) {
  self.scrollView.scrollEnabled = NO;
  if (self.scrollView.contentOffset.x < kScreen_Width *0.5) {
   return self.firstTableView;
  } else {
   return self.secondTableView;
  }
 } else {
  self.scrollView.scrollEnabled = YES;
  return [super hitTest:point withEvent:event];
 }
}

#pragma mark - 添加手势的相应方法

- (void)tapGestureAction:(UITapGestureRecognizer *)gesture
{
 CGPoint point = [gesture locationInView:self.topView];
 if (CGRectContainsPoint(self.topView.leftBtnFrame, point)) {
  if (self.scrollView.contentOffset.x > 0.5 * kScreen_Width) {
   [self.scrollView setContentOffset:CGPointMake(0, 0) animated:NO];
   self.topView.selectedItemIndex = 0;
  }
 } else if (CGRectContainsPoint(self.topView.rightBtnFrame, point)) {
  if (self.scrollView.contentOffset.x < 0.5 * kScreen_Width) {
   [self.scrollView setContentOffset:CGPointMake(kScreen_Width, 0) animated:NO];
   self.topView.selectedItemIndex = 1;
  }
 }
}

#pragma mark - firstTableView的代理方法scrollViewDidScroll

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
 CGFloat placeHolderHeight = self.topView.height - self.topView.itemHeight;

 CGFloat offsetY = scrollView.contentOffset.y;

 if (offsetY >= 0 && offsetY <= placeHolderHeight) {
  self.topView.y = -offsetY;
 }
 else if (offsetY > placeHolderHeight) {
  self.topView.y = - placeHolderHeight;
 }
 else if (offsetY <0) {
  self.topView.y = - offsetY;
 }
}

#pragma mark - secondTableView的代理方法scrollViewDidScroll

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
 CGFloat placeHolderHeight = self.topView.height - self.topView.itemHeight;
 CGFloat offsetY = scrollView.contentOffset.y;
 if (offsetY >= 0 && offsetY <= placeHolderHeight) {
  self.topView.y = -offsetY;
 } else if (offsetY > placeHolderHeight) {
  self.topView.y = - placeHolderHeight;
 } else if (offsetY <0) {
  self.topView.y = - offsetY;
 }
}