导航状态栏(UINavigationBar)和分栏状态栏(UITabBar)

2.3创建系统样式的按钮

    UIBarButtonItem *rightItem2 = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemCamera target:self action:nil];

    self.navigationItem.rightBarButtonItem = rightItem2;   

2.4创建自定义样式按钮

    UIView *view2 = [[UIView alloc]init];

    view2.frame = CGRectMake(0, 0, 30, 30);

    view2.backgroundColor =[UIColor redColor];

    UIBarButtonItem *rightItem3 = [[UIBarButtonItem alloc]initWithCustomView:view2];

    self.navigationItem.rightBarButtonItem = rightItem3;

2.5创建图片样式按钮

    UIImage *image = [UIImage imageNamed:@"user_total"];

    //强制设置图像为原始的描画方式显示

    UIImage *image1 = [image imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

    UIBarButtonItem *rightItem4 = [[UIBarButtonItem alloc]initWithImage:image1 style:UIBarButtonItemStyleDone target:nil action:nil];

    self.navigationItem.rightBarButtonItem = rightItem4;   

    //设置左元素项数组,并且会覆盖掉原有元素项

    self.navigationItem.leftBarButtonItems = @[rightItem2,rightItem3,rightItem4];

    //设置右元素项数组,并且会覆盖原有元素项

    self.navigationItem.rightBarButtonItems = @[rightItem2,rightItem3,rightItem4];

1.创建分栏元素项的方式1:系统自动创建

    FirstViewController *firstVC = [[FirstViewController alloc]init];

    firstVC.title = @"视图一";

    //tabBarItem为系统自动创建 lazily方法

    firstVC.tabBarItem.title = @"VC1";

    SecondViewController *secondVC = [[SecondViewController alloc]init];

2.创建分栏元素项的方式2:创建系统类型的按钮

    //参数1:系统风格类型

    //参数2:按钮的tag值

    UITabBarItem *item2 = [[UITabBarItem alloc]initWithTabBarSystemItem:UITabBarSystemItemFavorites tag:0];

    secondVC.tabBarItem = item2;

    secondVC.title = @"VC2";  

    ThirdViewController *thirdVC = [[ThirdViewController alloc]init];

3.创建分栏元素项的方式3:创建标题和图片样式的按钮

    UITabBarItem *item3 = [[UITabBarItem alloc]initWithTitle:@"视图三" image:[UIImage imageNamed:@"tab_0"] tag:0];

    thirdVC.tabBarItem = item3;

    FouthViewController *fouthVC = [[FouthViewController alloc]init];

4.创建分栏元素项的方式4:

    //按照图片原始方式绘制效果

    UIImage *image = [UIImage imageNamed:@"tab_friend_select"];

    UIImage *image1 = [image imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];

    UITabBarItem *item4 = [[UITabBarItem alloc]initWithTitle:@"视图四" image:[UIImage imageNamed:@"tab_friend_normal"] selectedImage:image1];

    fouthVC.tabBarItem = item4;