iOS：自定义导航栏，随着tableView滚动显示和隐藏

自定义导航栏，随着tableView滚动显示和隐藏

一、介绍

自定义导航栏是APP中很常用的一个功能，通过自定义可以灵活的实现动画隐藏和显示效果。虽然处理系统的导航栏也可以实现，但是这个是有弊端的，因为系统导航栏是全局的，在任何一个地方去修改导航栏内部的结构，其他地方都会改变，需要再次去特殊处理，否则很容易出现不可预知的bug。此时，自定义是最好的选择。

二、思想

（1）在控制器将要显示时，隐藏系统的导航栏，显示自定义的导航栏

（2）在控制器将要消失时，显示系统的导航栏，隐藏自定义的导航栏

（3）重写scrollView的代理方法，监测ContentOffst.y偏移，动态控制自定义的导航栏的可见性

三、定义

@interface XYQNavigationBar : UIView
@property (copy , nonatomic)void(^clickLeftItemBlock)();  // click left button block
@property (copy , nonatomic)void(^clickRightItemBlock)(); // click right button block
@property (copy , nonatomic)NSString *title; // title
@property (assign,nonatomic)UIColor  *titleColor; // title color
@property (strong,nonatomic)UIColor  *navBackgroundColor;// navagationBar background color
@property (strong,nonatomic)UIImage  *navBackgroundImage;// navigationBar background image

+(instancetype)createCustomNavigationBar;  //create navigationBar
-(void)showCustomNavigationBar:(BOOL)show; //set navigationBar hide, defalut is NO
-(void)setupBgImageAlpha:(CGFloat)alpha animation:(NSTimeInterval)duration compeleteBlock:(void (^)())compeleteBlock;// navigationBar background image alpha
-(void)setupBgColorAlpha:(CGFloat)alpha animation:(NSTimeInterval)duration compeleteBlock:(void (^)())compeleteBlock;// navigationBar background color alpha
-(void)setLftItemImage:(NSString *)imgName leftItemtitle:(NSString *)leftItemtitle textColor:(UIColor *)color; // navigationBar left  button has title and image
-(void)setRightItemImage:(NSString *)imgName rightItemtitle:(NSString *)rightItemtitle textColor:(UIColor *)color;// navigationBar right  button has title and image
-(void)setLeftItemImage:(NSString *)imgName;  // navigationBar left  button only has image
-(void)setRightItemImage:(NSString *)imgName; // navigationBar right button only has image
@end

四、实现

（）创建

- (void)viewDidLoad {
    [super viewDidLoad];

    //init
    self.tableView = [[UITableView alloc] initWithFrame:self.view.bounds];
    self.tableView.dataSource = self;
    self.tableView.delegate = self;
    self.navigationBar = [XYQNavigationBar createCustomNavigationBar];

    //update（此处可以*改变导航栏的属性值）
    self.navigationBar.title = @"自定义导航栏";

    //block
    __weak typeof(self) weakSelf = self;
    self.navigationBar.clickLeftItemBlock = ^(){
        [weakSelf.navigationController popViewControllerAnimated:YES];
    };
    self.navigationBar.clickRightItemBlock = ^(){
        [weakSelf.navigationController pushViewController:[[SecondViewController alloc] init] animated:YES];
    };

    // add
    [self.view addSubview:self.tableView];
    [self.view addSubview:self.navigationBar];
}

 （）显示

-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];

    //hide system navigationBar
    [self.navigationController setNavigationBarHidden:YES animated:YES];

    //show custom navigationBar
    [self.navigationBar showCustomNavigationBar:YES];
}

 （）隐藏

-(void)viewWillDisappear:(BOOL)animated{
    [super viewWillDisappear:animated];

    //show system navigationBar
    [self.navigationController setNavigationBarHidden:NO animated:YES];

    //hide custom navigationBar
    [self.navigationBar showCustomNavigationBar:NO];
}

 （）监测

#pragma mark - public methods
// animation show or hide navigationbar
-(void)scrollViewDidScroll:(UIScrollView *)scrollView{
    CGFloat offsetY = scrollView.contentOffset.y;
    CGFloat colorOffset = offsetY / 64.0;
    colorOffset = colorOffset >  ?  : colorOffset;

    //method 1 : change backgrundViewImage alpha
    [self.navigationBar setupBgImageAlpha:colorOffset animation:0.4 compeleteBlock:nil];

    //method 2 : change backgrundViewColor alpha
    //[self.navigationBar setupBgColorAlpha:colorOffset animation:0.4 compeleteBlock:nil];

}

五、效果

六、下载

github：https://github.com/xiayuanquan/XYQNavigationBar.git