iOS使用自带的UIViewController实现qq加号下拉菜单的功能(实例代码)

//重置控制器的大小 
-(CGSize)preferredContentSize{ 
 if (self.popoverPresentationController != nil) { 
  CGSize tempSize ; 
  tempSize.height = self.view.frame.size.height; 
  tempSize.width = 150; 
  CGSize size = [_tableVIew sizeThatFits:tempSize]; 
  return size; 
 }else{ 
  return [super preferredContentSize]; 
 } 
} 

environmentView.addMenuCallBack = ^(UIButton *sender){ 
  // 设置大小 
  weakPopView.preferredContentSize = CGSizeMake(120, 150); 
  // 设置 Sytle 
  weakPopView.modalPresentationStyle = UIModalPresentationPopover; 
  // 需要通过 sourceView 来判断位置的 
  weakPopView.popoverPresentationController.sourceView = sender; 
  //可以指示小箭头颜色 
  weakPopView.popoverPresentationController.backgroundColor = [UIColor whiteColor]; 
  // 设置指示箭头的位置 
  weakPopView.popoverPresentationController.sourceRect = CGRectMake(0, 0, sender.frame.size.width*3/4, sender.frame.size.height); 
  // 箭头方向 
  weakPopView.popoverPresentationController.permittedArrowDirections = UIPopoverArrowDirectionUp; 
  // 设置代理 
  weakPopView.popoverPresentationController.delegate = weakSelf; 
  [weakSelf presentViewController:weakPopView animated:YES completion:nil]; 
 };