tableView下拉放大头部视图

//先实现 UIScrollViewDelegate  代理

//headVIewHeight : tableview 的头试图高度

//headView  : tableView 的头视图

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {

CGFloat yOffset =tbView.contentOffset.y;

CGFloat nowHeight =fabs(yOffset) + headVIewHeight;

CGFloat nowWid = (nowHeight /headVIewHeight) *kDeviceWidth;

if (yOffset < 0)

{

[headView setFrame:CGRectMake(-(nowWid -kDeviceWidth) / 2.0,-(nowHeight -headVIewHeight), nowWid, nowHeight)

}

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