UIPopoverController和UIPopoverPre

CGRect btnF = CGRectMake(200, 200, 100, 50);
UIButton *button = [[UIButton alloc] initWithFrame:btnF];
button.backgroundColor = [[UIColor brownColor] colorWithAlphaComponent:0.5];
[self.view addSubview:button];
[button addTarget:self action:@selector(present:) forControlEvents:UIControlEventTouchUpInside];

UIPopoverController

- (void)present:(UIButton *)sender {
    
    FirstViewController *cityListVC = [[FirstViewController alloc] init];
    //将cityListVC塞进_popover
    _popover = [[UIPopoverController alloc] initWithContentViewController:cityListVC];
    //设置_popover的尺寸
    _popover.popoverContentSize = CGSizeMake(100, 100);
    //设置代理
    _popover.delegate = self;
    //展示_popover
    [_popover presentPopoverFromRect:button.bounds inView:button permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES];
}

UIPopoverPresentationController

- (void)present:(UIButton *)sender {

    cityListVC.preferredContentSize = CGSizeMake(100, 100);
    cityListVC.modalPresentationStyle = UIModalPresentationPopover;
    UIPopoverPresentationController *popController = [cityListVC popoverPresentationController];
    popController.sourceView = sender;
    popController.sourceRect = sender.bounds;
    popController.delegate = self;
    popController.permittedArrowDirections = UIMenuControllerArrowDown;
    [self presentViewController:cityListVC animated:YES completion:nil];
}

- (void)present:(UIButton *)sender {
    
    _hallManagerNav = [[UINavigationController alloc] initWithRootViewController:cityListVC];
    UIBarButtonItem *item = [[UIBarButtonItem alloc] initWithTitle:@"关闭" style:(UIBarButtonItemStylePlain) target:self action:@selector(closePresentCtr)];
    [cityListVC.navigationItem setRightBarButtonItem:item];
    //弹出时动画风格
    _hallManagerNav.modalTransitionStyle =UIModalTransitionStyleCrossDissolve;
    //弹出风格
    _hallManagerNav.modalPresentationStyle = UIModalPresentationFormSheet;
    [self presentViewController:_hallManagerNav animated:YES completion:nil];
}

typedef NS_ENUM(NSInteger, UIModalTransitionStyle) {
    UIModalTransitionStyleCoverVertical = 0,
    UIModalTransitionStyleFlipHorizontal __TVOS_PROHIBITED,
    UIModalTransitionStyleCrossDissolve,
    UIModalTransitionStylePartialCurl NS_ENUM_AVAILABLE_IOS(3_2) __TVOS_PROHIBITED,
};

typedef NS_ENUM(NSInteger, UIModalPresentationStyle) {
        UIModalPresentationFullScreen = 0,
        UIModalPresentationPageSheet NS_ENUM_AVAILABLE_IOS(3_2) __TVOS_PROHIBITED,
        UIModalPresentationFormSheet NS_ENUM_AVAILABLE_IOS(3_2) __TVOS_PROHIBITED,
        UIModalPresentationCurrentContext NS_ENUM_AVAILABLE_IOS(3_2),
        UIModalPresentationCustom NS_ENUM_AVAILABLE_IOS(7_0),
        UIModalPresentationOverFullScreen NS_ENUM_AVAILABLE_IOS(8_0),
        UIModalPresentationOverCurrentContext NS_ENUM_AVAILABLE_IOS(8_0),
        UIModalPresentationPopover NS_ENUM_AVAILABLE_IOS(8_0) __TVOS_PROHIBITED,
        UIModalPresentationNone NS_ENUM_AVAILABLE_IOS(7_0) = -1,         
};