popover （iphone && ipad）
_setVC 为设置界面；
添加 <UIPopoverPresentationControllerDelegate>；
- (void)leftBtnClick:(UIButton*)sender{
if(_setVC) {
[self dismissViewControllerAnimated:YES completion:nil];
_setVC=nil;
}
_setVC = [[ASettingViewController alloc] init];
[_setVC setDelegate:self];
//设置弹出的样式为popover
_setVC.modalPresentationStyle = UIModalPresentationPopover;
//设置弹出控制器的尺寸
_setVC.preferredContentSize = CGSizeMake(120, 120);
//设置popoverPresentationController的sourceRect和sourceView属性
_setVC.popoverPresentationController.sourceRect = sender.bounds;
_setVC.popoverPresentationController.sourceView = sender;
//设置箭头方向
_setVC.popoverPresentationController.permittedArrowDirections = UIPopoverArrowDirectionUp;
//设置背景色,包括箭头
_setVC.popoverPresentationController.backgroundColor = [UIColor colorWithWhite:0.3 alpha:0.5];
_setVC.popoverPresentationController.delegate = self;
//弹出
[self presentViewController:_setVC animated:YES completion:nil];
}
#pragma mark - UIPopoverPresentationControllerDelegate
//实现该代理方法,返回UIModalPresentationNone值,可以在iPhone设备实现popover效果
-(UIModalPresentationStyle)adaptivePresentationStyleForPresentationController:(UIPresentationController*)controller{
return UIModalPresentationNone;//不适配(不区分ipad或iPhone)
}
