导航栏，状态栏,底部高度

// 状态栏高度
CGFloat statusBarHeight = [[UIApplication sharedApplication] statusBarFrame].size.height;
// 导航栏高度
CGFloat navBarHeight = self.navigationController.navigationBar.frame.size.height;
X以前： 20，44
x以及以后：44，44

//状态栏和导航条高度

#define getRectNavAndStatusHight  self.navigationController.navigationBar.frame.size.height+[[UIApplication sharedApplication] statusBarFrame].size.height

x 底部高度:34

二。
创建一个UINavigationController
@interface ABNavigationController : UINavigationController
1.统一设置title颜色和大小

self.navigationBar.titleTextAttributes = @{NSForegroundColorAttributeName:[UIColor whiteColor],NSFontAttributeName:[UIFont boldSystemFontOfSize:17]};

2.统一设置导航条

#pragma mark 重写push方法 导航栏按钮
- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated {
    
//    if (self.pushing == YES) {
//        NSLog(@"被拦截");
//        return;
//    } else {
//        NSLog(@"push");
//        self.pushing = YES;
//    }
    if (self.childViewControllers.count > 0) { // 如果push进来的不是第一个控制器
        UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
        //[button setTitle:@"返回" forState:UIControlStateNormal];
        [button setImage:[UIImage imageNamed:@"问题反馈"] forState:UIControlStateNormal];
       // [button setImage:[UIImage imageNamed:@"刷新"] forState:UIControlStateHighlighted];
        button.size = CGSizeMake(70, 30);
//下面两行设置图片位置和大小
        [button setImageEdgeInsets:UIEdgeInsetsMake(5, -5, 5, 0)];//上左下右
        button.imageView.contentMode = UIViewContentModeScaleAspectFit;
        // 让按钮内部的所有内容左对齐
        button.contentHorizontalAlignment = UIControlContentHorizontalAlignmentLeft;
        //        [button sizeToFit];
        // 让按钮的内容往左边偏移10
      //  button.contentEdgeInsets = UIEdgeInsetsMake(0, -10, 0, 0);//上左下右
      //  [button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
      //  [button setTitleColor:[UIColor redColor] forState:UIControlStateHighlighted];
        [button addTarget:self action:@selector(popViewControllerAnimated:) forControlEvents:UIControlEventTouchUpInside];
        [button setBackgroundColor:[UIColor redColor]];
        // 修改导航栏左边的item
        viewController.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:button];
        
        // 隐藏tabbar
        viewController.hidesBottomBarWhenPushed = YES;
    }
    
    // 这句super的push要放在后面, 让viewController可以覆盖上面设置的leftBarButtonItem
    // 意思是，我们任然可以重新在push控制器的viewDidLoad方法中设置导航栏的leftBarButtonItem，如果设置了就会覆盖在push方法中设置的“返回”按钮，因为 [super push....]会加载push的控制器执行viewDidLoad方法。
        [super pushViewController:viewController animated:animated];
}

UINavigationBar透明设置

- (void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    
    
    
    [self.navigationController.navigationBar setTranslucent:YES];//设置透明度

    //    //颜色字体
    self.navigationController.navigationBar.titleTextAttributes = @{NSForegroundColorAttributeName:kWhiteColor,NSFontAttributeName:[UIFont boldSystemFontOfSize:17]};
    
    
    
    UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
    [button setImage:[UIImage imageNamed:@"icon_back"] forState:UIControlStateNormal];
    button.size = CGSizeMake(70, 44);
    [button setImageEdgeInsets:UIEdgeInsetsMake(5, 5, 5, 0)];//上左下右
    button.imageView.contentMode = UIViewContentModeScaleAspectFit;
    button.contentHorizontalAlignment = UIControlContentHorizontalAlignmentLeft;
    [button addTarget:self action:@selector(backBtn) forControlEvents:UIControlEventTouchUpInside];
    self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:button];
    //状态栏
//1.在info.plist中添加View controller-based status bar appearance,值为NO


    [UIApplication sharedApplication].statusBarStyle = UIStatusBarStyleLightContent;
}

- (void)viewWillDisappear:(BOOL)animated{
    [super viewWillDisappear:animated];
    
    [self.navigationController.navigationBar setTranslucent:NO];//设置透明度

    [UIApplication sharedApplication].statusBarStyle = UIStatusBarStyleDefault;//状态栏
    //颜色字体
    self.navigationController.navigationBar.titleTextAttributes = @{NSForegroundColorAttributeName:kNavTitleColor,NSFontAttributeName:[UIFont boldSystemFontOfSize:17]};
    
}