一、設(shè)置導(dǎo)航欄底線

1. 簡(jiǎn)單獲取底線

- (UIView *)navLine {
    if (!_navLine) {
        UIView *backgroundView = [self.navigationController.navigationBar subviews].firstObject;
        _navLine = backgroundView.subviews.firstObject;        
    }
    return _navLine;
}

2.單個(gè)頁(yè)面設(shè)置隱藏顯示

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    self.navLine.hidden = YES;
}

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    self.navLine.hidden = NO;    
}

二徙鱼、設(shè)置導(dǎo)航欄背景圖
1.設(shè)置導(dǎo)航欄背景圖所需的各個(gè)尺寸
1倍圖 640 * 128 px (一般用不到)
2倍圖 750 * 128 px (5s，6全度，6s, 7)
3倍圖 1242*192 px (6p, 6sp)
備注：其實(shí)一般兩種圖就足夠幔妨，5s也是用2倍圖，現(xiàn)在一般最低適配到5s傍菇，當(dāng)然如果需求不一樣就三張猾瘸。

設(shè)置導(dǎo)航背景圖代碼

/*設(shè)置圖片拉伸范圍 如果圖片被擠壓變形的情況下*/
   UIImage *backImage = [UIImage imageNamed:@"homeNav"]; 
   backImage = [backImage resizableImageWithCapInsets:UIEdgeInsetsMake(0, 100, 10, 10)];

/*設(shè)置背景圖*/
   [self.navigationController.navigationBar setBackgroundImage:backImage forBarMetrics:UIBarMetricsDefault];

設(shè)置導(dǎo)航條背景圖片時(shí)有時(shí)self.view會(huì)向下偏移64像素

//此句代碼解決坐標(biāo)問(wèn)題

[self.navigationController.navigationBar setTranslucent:YES];

//當(dāng)translucent = YES，controller中self.view的原點(diǎn)是從導(dǎo)航欄左上角開(kāi)始計(jì)算

//當(dāng)translucent = NO丢习，controller中self.view的原點(diǎn)是從導(dǎo)航欄左下角開(kāi)始計(jì)算

設(shè)置導(dǎo)航欄背景純色

   UINavigationBar *bar = [UINavigationBar appearance];
   bar.barTintColor = [UIColor colorWithRed:62/255.0 green:173/255.0 blue:176/255.0 alpha:1.0];

設(shè)置導(dǎo)航欄title字體類型和大小

 [self.navigationController.navigationBar setTitleTextAttributes:@{
                                                                      NSFontAttributeName:[UIFont fontWithName:@"Helvetica-Bold" size:22],
                                                                      NSForegroundColorAttributeName:[UIColor whiteColor]
                                                                      }];

設(shè)置導(dǎo)航欄透明

- (void)viewWillAppear:(BOOL)animated {
    
    [super viewWillAppear:animated];
    
    [self.navigationController.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];    
    [self.navigationController.navigationBar setShadowImage:[UIImage new]];
    
}

- (void)viewWillDisappear:(BOOL)animated {
    
    [super viewWillDisappear:animated];
    
    [self.navigationController.navigationBar setBackgroundImage:nil forBarMetrics:UIBarMetricsDefault];``    
    [self.navigationController.navigationBar setShadowImage:nil];
}