code2：
* - (IBAction)popOver:(id)sender {
    AddressViewController *contentVC = [[AddressViewController alloc] init];
    contentVC.modalPresentationStyle = UIModalPresentationPopover;
    contentVC.popoverPresentationController.sourceView = self.view;
    contentVC.popoverPresentationController.sourceRect = CGRectMake(100, 100, 100, 100);
    contentVC.popoverPresentationController.permittedArrowDirections = UIPopoverArrowDirectionUp;
    [self presentViewController:contentVC animated:YES completion:nil];
}
* AddressViewController.m
* #import "AddressViewController.h"

@interface AddressViewController () <UITableViewDelegate, UITableViewDataSource>

@property (weak, nonatomic) IBOutlet UITableView *masterTableView; // 省份tableView
@property (weak, nonatomic) IBOutlet UITableView *detailTableView; // 地区tableView

@property (nonatomic, strong) NSArray *masterDataSource;           // 省份数据源
@property (nonatomic, strong) NSArray *detailDataSource;           // 地区数据源
@property (nonatomic, assign) int masterIndex;                     // 选中的省份

@end

@implementation AddressViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    _masterIndex = 0;
    self.preferredContentSize = CGSizeMake(150, 300);
}

- (NSArray *)masterDataSource {
    if (_masterDataSource == nil) {
        _masterDataSource = @[@"河南", @"河北", @"江苏", @"浙江", @"广东"];
    }
    return _masterDataSource;
}

- (NSArray *)detailDataSource {
    if (_detailDataSource == nil) {
        _detailDataSource = @[@[@"郑州", @"洛阳", @"周口", @"开封"],
                              @[@"石家庄", @"石家庄2"],
                              @[@"南京", @"苏州", @"淮安", @"淮北", @"句容"],
                              @[@"杭州", @"温州", @"台州", @"宁波", @"瑞安", @"苍南"],
                              @[@"广州", @"深圳"]
                              ];
    }
    return _detailDataSource;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    if (tableView == self.masterTableView) {
        return self.masterDataSource.count;
    }

    if (tableView == self.detailTableView) {
        return [self.detailDataSource[_masterIndex] count];
    }
    return 0;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    if (tableView == self.masterTableView) {
        UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"master"];
        if (cell == nil) {
            cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"master"];
        }
        cell.textLabel.text = self.masterDataSource[indexPath.row];
        return cell;
    }
    
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"detail"];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"detail"];
    }
    cell.textLabel.text = self.detailDataSource[_masterIndex][indexPath.row];
    return cell;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    if (tableView == _masterTableView) {
        _masterIndex = (int)indexPath.row;
        self.preferredContentSize = CGSizeMake(300, 300);
        [_detailTableView reloadData];
    }
    
    if (tableView == _detailTableView) {
        self.preferredContentSize = CGSizeMake(150, 300);
        [_detailTableView reloadData];
    }
}

@end