push & present

如果讓一個(gè)ViewController擁有navigationBar，有2種方式

-1- UINavigationController

這種方式是比較常見(jiàn)的一種简肴，也是最簡(jiǎn)單的一種晃听，但如果封裝起來(lái)一個(gè)controller供外部直接調(diào)用，就顯得有點(diǎn)不簡(jiǎn)潔了砰识。 ** 而且能扒，這種方式不支持push進(jìn)去**

比如：一個(gè)掃二維碼的page

(1) nav vc -- 供外部調(diào)用，是一個(gè)UINavigationController的子類

@interface QRCodeReaderViewController : UINavigationController

-(instancetype)initWithQRDelegate: (id)delegate;

@end

// 實(shí)現(xiàn)
-(instancetype)initWithQRDelegate: (id)delegate{
    return [super initWithRootViewController: [[QRCodeReaderController alloc] initWithDelegate:delegate]];
}

(2) root vc -- 自己內(nèi)部封裝辫狼，掃碼功能實(shí)現(xiàn)

@interface QRCodeReaderController : UIViewController

-(instancetype)initWithQRDelegate: (id)delegate;

@end

// 核心類實(shí)現(xiàn)
-(instancetype)initWithQRDelegate:(id)delegate{
    if (self = [super init]) {
        _delegate = delegate;
    }
    return self;
}

• 這里很明顯就有了一個(gè)很雞肋的地方初斑，就是root vc里的接口方法，必須和nav vc一致膨处，不然就沒(méi)法初始化傳參數(shù)见秤，或進(jìn)行一系列直接的操作了

• 如果對(duì)外的接口方法有很多的話砂竖，在root vc里也要提供和nav vc一致的很多方法，顯得很累贅鹃答。

所以又發(fā)現(xiàn)了比較簡(jiǎn)潔的第二種方法乎澄。

-2- UIViewController + UINavigationBar

實(shí)現(xiàn)思路：[self.view addSubview:self.navigationBar]

簡(jiǎn)單說(shuō)，就是將自定義的一個(gè)navigationBar作為self.view的一個(gè)subView测摔，模擬導(dǎo)航欄置济，好處是定制化程度高，可任意指定frame锋八。

核心代碼：

//
//  TestViewController.m
//  UINavigationBarDemo
//
//  Created by zhuxuhong on 16/9/6.
//  Copyright ? 2016年 zhuxuhong. All rights reserved.
//

#import "TestViewController.h"

typedef NS_ENUM(NSInteger, NavBarItemType) {
    NavBarItemCancel,
    NavBarItemOk,
    NavBarItemRedo,
};

@interface TestViewController ()

@property(nonatomic, strong)UINavigationBar *navigationBar;

@end

@implementation TestViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self buildNavBar];
}

-(void)buildNavBar{
    self.view.backgroundColor = [UIColor whiteColor];
    [self.view addSubview: self.navigationBar];
}

/**
 *  navigation bar
 */
-(UINavigationBar *)navigationBar{
    if (!_navigationBar) {
        if (self.navigationController) {
            // 隱藏原有nav bar
            [self.navigationController setNavigationBarHidden:true animated:true];
        }
        
        CGRect frame = self.view.bounds;
        frame.size.height = 64; //可任意設(shè)置frame
        UINavigationBar *bar = [[UINavigationBar alloc] initWithFrame:frame];
        bar.barStyle = UIBarStyleDefault;
        bar.translucent = false;
        bar.autoresizingMask = UIViewAutoresizingFlexibleWidth;
        bar.barTintColor = [UIColor redColor];
        bar.tintColor = [UIColor whiteColor];
        bar.titleTextAttributes = @{ NSForegroundColorAttributeName: [UIColor whiteColor] };
        
        // bar button items
        UIBarButtonItem *cancelItem = [[UIBarButtonItem alloc] initWithTitle:@"取消" style:UIBarButtonItemStylePlain target:self action:@selector(navBarButtonItemDidClick:)];
        cancelItem.tag = NavBarItemCancel;
        
        UIBarButtonItem *okItem = [[UIBarButtonItem alloc] initWithTitle:@"確定" style:UIBarButtonItemStylePlain target:self action:@selector(navBarButtonItemDidClick:)];
        okItem.tag = NavBarItemOk;
        
        UIBarButtonItem *redoItem = [[UIBarButtonItem alloc] initWithTitle:@"撤銷" style:UIBarButtonItemStylePlain target:self action:@selector(navBarButtonItemDidClick:)];
        redoItem.tag = NavBarItemRedo;
        
        // nav item
        UINavigationItem *navItem = [[UINavigationItem alloc] initWithTitle:@"UINavigationBar"];
        navItem.leftBarButtonItem = cancelItem;
        navItem.rightBarButtonItems = @[okItem, redoItem];
        [bar pushNavigationItem:navItem animated:false];
        _navigationBar = bar;
    }
    
    return _navigationBar;
}

// nav bar button item did click
-(void)navBarButtonItemDidClick: (UIBarButtonItem*)sender{
    switch (sender.tag) {
        case NavBarItemCancel:
            [self backToPreviousPage];
            break;
        case NavBarItemOk:
            [self backToPreviousPage];
            break;
        case NavBarItemRedo:
            
            break;
        default:
            break;
    }
}

/**
 *  back to previous page
 */
-(void)backToPreviousPage{
    if (self.navigationController) {
        [self.navigationController popViewControllerAnimated:true];
        // 顯示nav bar
        [self.navigationController setNavigationBarHidden:false animated:false];
    }
    else{
        [self dismissViewControllerAnimated:true completion:nil];
    }
}

@end

這種方法的好處是：

• 無(wú)論是以presentViewController還是pushViewController的方式呈現(xiàn)舟肉，都不會(huì)影響你的navigationBar的定制化展現(xiàn)。

使用

- (IBAction)push:(id)sender {
    [self.navigationController pushViewController:[TestViewController new] animated:true];
}

- (IBAction)present:(id)sender {
    [self presentViewController:[TestViewController new] animated:true completion:nil];
}