关于table跳转的疑虑，手写了为什么跳转不了（只写了前两个单元格），我是小白请原谅

#import "RootTableViewController.h"
#import "TableViewController_1.h"
#import "TableViewController_2.h"
@interface RootTableViewController ()

@end

@implementation RootTableViewController

• (void)viewDidLoad {
  [super viewDidLoad];
  self.title = @"设置";
  _muArr = @[@[@"飞行模式",@"无线局域网",@"蓝牙",@"蜂窝移动网络",@"个人热点",@"运营商"],@[@"通知",@"控制中心",@"勿扰模式"]];
  }

• (void)didReceiveMemoryWarning {
  [super didReceiveMemoryWarning];

}

• (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
  return [_muArr count];
  }

• (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
  return ((NSArray *)_muArr[section]).count;
  }

• (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
  UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"rootCellIdentifier" forIndexPath:indexPath];
  if (cell == nil) {
  cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"rootCellIdentifier"];
  }
  cell.textLabel.text = [((NSArray *)_muArr[indexPath.section]) objectAtIndex:(indexPath.row)];
  cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
  return cell;
  }

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
TableViewController_1 *table_1 = [[TableViewController_1 alloc]init];
TableViewController_2 *table_2 = [[TableViewController_2 alloc]init];
UIViewController *uiviewcontroller = [[UIViewController alloc]init];
if (indexPath.section == 0) {
switch (indexPath.row) {
case 0:
uiviewcontroller = table_1;
break;
case 1:
uiviewcontroller = table_2;
break;
default:
break;
}
}

[self.navigationController pushViewController:uiviewcontroller animated:YES];

}
@end
／＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊／
#import "TableViewController_1.h"

@interface TableViewController_1 ()

@end

@implementation TableViewController_1

• (void)viewDidLoad {
  [super viewDidLoad];
  _arr_1 = @[@[@"你该吃药了",@"你病的不轻"],@[@"我是医生",@"我是你的医生",@"我是你一辈子的医生"]];
  }

• (void)didReceiveMemoryWarning {
  [super didReceiveMemoryWarning];
  }

#pragma mark - Table view data source

• (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
  return _arr_1.count;
  }

• (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
  return ((NSArray *)_arr_1[section]).count;
  }

• (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
  UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"cellIdentifier" forIndexPath:indexPath];

  // Configure the cell...
  if (cell == nil) {
  cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"cellIdentifier"];
  }
  cell.textLabel.text = ((NSArray *)_arr_1[indexPath.section])[indexPath.row];
  cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
  return cell;
  }

tableview没有设置数据源和代理。