Objective-C 继承新的认识以及作用

摘要: 继承是一个非常常见的

iOS 三大特性 继承 多态 以及 封装

下面就是对继承的更为深刻的认识。

假如你准备重写NavigationView 那么就需要让其自动生成返回键 以及其他功能。

如：

#import <UIKit/UIKit.h>

@interface ParentClassController : UIViewController
@property(nonatomic,strong)UIView * NavigationView;//头部导航栏
@property(nonatomic,strong)UIButton * NavigationBack;//返回上级菜单
@property(nonatomic,strong)UILabel * TitleName;//标题

@property(nonatomic,strong)UIButton * Share;//分享

-(void)initVariable;//初始化变量
-(void)initView;//初始化界面
-(void)initData;//初始化数据
-(void)setNavigationItems;//设置导航栏信息

#import "ParentClassController.h"

@interface ParentClassController ()

@end

@implementation ParentClassController

- (void)viewDidLoad {
[super viewDidLoad];
[self initVariable];
[self initData];
[self initView];
[self setNavigationItems];
}
#pragma mark--初始化变量
-(void)initVariable{

}
#pragma mark--初始化界面
-(void)initView{
/*
跳转模式：原生4种
1. 默认：UIModalTransitionStyleCoverVertical 上下弹出
2.UIModalTransitionStyleFlipHorizontal 翻转
3.UIModalTransitionStyleCrossDissolve  淡入
4.UIModalTransitionStylePartialCurl 翻页动画
*/
}
#pragma mark--初始化数据
-(void)initData{

}

#pragma mark--设置导航栏信息
-(void)setNavigationItems{
//基类最基础的返回 主题 以及去购物车
//导航
_NavigationView=[[UIView alloc]initWithFrame:CM(0, 20, VIEW_WIDTH, 44)];
_NavigationView.backgroundColor=UINavigationColor;
_NavigationView.layer.borderWidth=0.4;
_NavigationView.layer.borderColor=[UIColor grayColor].CGColor;
[self.view addSubview:_NavigationView];

//返回
_NavigationBack=[UIButton buttonWithType:UIButtonTypeCustom];
_NavigationBack.tag=1;
_NavigationBack.frame=CM(10, 10, 25, 25);
UIImage *imgMenu =[[UIImage imageNamed:@"Back"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
[_NavigationBack setImage:imgMenu forState:UIControlStateNormal];
[_NavigationBack setImage:[UIImage imageNamed:@"back-1" ]forState:UIControlStateHighlighted];

[_NavigationBack addTarget:self action:@selector(HomeNavigationButton:) forControlEvents:UIControlEventTouchUpInside];
[self.NavigationView addSubview:_NavigationBack];
//主题
_TitleName=[[UILabel alloc]initWithFrame:CM(VIEW_WIDTH/2-50, 12, 100, 20)];
_TitleName.text=@"海涛展示厅";
_TitleName.textColor=[UIColor whiteColor];
_TitleName.textAlignment = NSTextAlignmentCenter;
[self.NavigationView addSubview:_TitleName];

//分享
_Share=[[UIButton alloc]initWithFrame:CM(VIEW_WIDTH-40, 10, 25, 25)];
_Share.tag=2;
UIImage * imageShare=[[UIImage imageNamed:@"分享" ]imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
[_Share setImage:imageShare forState:UIControlStateNormal];
[_Share setImage:[UIImage imageNamed:@"分享-1"] forState:UIControlStateHighlighted];
[self.NavigationView addSubview:_Share];
[_Share addTarget:self action:@selector(HomeNavigationButton:) forControlEvents:UIControlEventTouchUpInside];
self.view.backgroundColor=[UIColor whiteColor];

}

#pragma mark--界面按钮
-(void)HomeNavigationButton:(UIButton *)sender{

switch (sender.tag) {
case 0:
{

}
break;
case 1:
{
// 返回上一级
[self dismissViewControllerAnimated:YES completion:nil];
// 返回首页[self.navigationController popToRootViewControllerAnimated:YES];
NSLog(@"返回");
}
case 2:
{
NSLog(@"分享");
}
default:
break;
}
}

- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

下面这个类继承了

#import <UIKit/UIKit.h>
//注意继承
@interface SearchViewController : ParentClassController

@end

//
//  Created by 杭州晶泰电子商务有限公司 on 16/3/16.
//  Copyright © 2016年 杭州晶泰电子商务有限公司. All rights reserved.
//

#import "SearchViewController.h"

@interface SearchViewController ()

@end

@implementation SearchViewController

- (void)viewDidLoad {
[super viewDidLoad];

}

- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];

}

这个类就是就是一个所有的Controller的基类

只要继承该类就会自动生成返回键以及分享功能

注意：在继承的时候，如果遇到调用两次方法 那么可能你在子类中调用了该方法。并且你在

子类中的viewDidLoad中调用了[super viewDidLoad];

那么子类重写了父类的方法那么你调用[super viewDidLoad]

在子类中就不要在调用重写的方法了，因为[super viewDidLoad]已经调用过了。

- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
}