新浪微博自定制TabBar

转载请标明出处：http://blog.csdn.net/android_ls/article/details/45896395

声明：仿新浪微博项目，所用所有图片资源都来源于官方新浪微博IOS客户端，编写本应用的目的在于学习交流，如涉及侵权请告知，我会及时换掉用到的相关图片。

自定义UITabBar替换系统默认的，目的是为了在UITabBar中间位置添加一个“+号按钮”，下面我们来聊聊具体的实现。

1、自定义WBTabBar，让其继承自UITabBar，代码如下：

//
//  WBTabBar.h
//  SinaWeibo
//
//  Created by android_ls on 15/5/21.
//  Copyright (c) 2015年 android_ls. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface WBTabBar : UITabBar

@end

2、tabBar是UITabBarController的只读成员变量（属性），是不让修改的，在UITabBarController.h文件中的声明如下：

@property(nonatomic,readonly) UITabBar *tabBar NS_AVAILABLE_IOS(3_0);

针对于这种情况，我们可以使用KVC的方式，更换系统自带的UITabBar，实现代码如下：

    WBTabBar *tabBar = [[WBTabBar alloc] init];
    [self setValue:tabBar forKeyPath:@"tabBar"];

3、添加一个UIButton到WBTabBar中，实现代码如下：

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // 添加一个按钮到tabbar中
        UIButton *plusBtn = [[UIButton alloc] init];
        [plusBtn setBackgroundImage:[UIImage imageNamed:@"tabbar_compose_button"] forState:UIControlStateNormal];
        [plusBtn setBackgroundImage:[UIImage imageNamed:@"tabbar_compose_button_highlighted"] forState:UIControlStateHighlighted];
        [plusBtn setImage:[UIImage imageNamed:@"tabbar_compose_background_icon_add"] forState:UIControlStateNormal];
        [plusBtn setImage:[UIImage imageNamed:@"tabbar_compose_icon_add_highlighted"] forState:UIControlStateHighlighted];
        plusBtn.size = plusBtn.currentBackgroundImage.size;
        [plusBtn addTarget:self action:@selector(plusClick) forControlEvents:UIControlEventTouchUpInside];
        [self addSubview:plusBtn];
        self.plusBtn = plusBtn;
    }
    return self;
}

4、设置加号按钮的位置，调整WBTabBar中各个UITabBarButton的位置和宽度，具体实现代码如下：

- (void)layoutSubviews
{
    [super layoutSubviews];
    
    // 1.设置加号按钮的位置
    self.plusBtn.centerX = self.width * 0.5;
    self.plusBtn.centerY = self.height * 0.5;
    
    // 2.设置其它UITabBarButton的位置和尺寸
    CGFloat tabbarButtonW = self.width / 5;
    CGFloat tabbarButtonIndex = 0;
    for (UIView *child in self.subviews) {
        Class class = NSClassFromString(@"UITabBarButton");
        if ([child isKindOfClass:class]) {
            // 设置宽度
            child.width = tabbarButtonW;
            // 设置x
            child.x = tabbarButtonIndex * tabbarButtonW;
            
            // 增加索引
            tabbarButtonIndex++;
            if (tabbarButtonIndex == 2) {
                tabbarButtonIndex++;
            }
        }
    }
}

5、定义WBTabBarDelegate协议，声明WBTabBar的代理，代码如下：

//
//  WBTabBar.h
//  SinaWeibo
//
//  Created by android_ls on 15/5/21.
//  Copyright (c) 2015年 android_ls. All rights reserved.
//

#import <UIKit/UIKit.h>

#pragma mark 因为在UITabBar中已经声明过一个UITabBarDelegate协议，
#pragma mark 我们若想新增一个对外的代理函数，可以让我们自定义的协议继承自UITabBarDelegate，添加一个扩展函数。

@class WBTabBar;

@protocol WBTabBarDelegate <UITabBarDelegate>

@optional
- (void)tabBarDidClickPlusButton:(WBTabBar *)tabBar;

@end

@interface WBTabBar : UITabBar

@property (nonatomic, weak) id<WBTabBarDelegate> tabBarDelegate;

@end

6、在加号按钮的点击事件处理器中，通知代理

#pragma mark 加号按钮点击事件处理器
- (void)plusClick
{
    // 通知代理
    if ([self.tabBarDelegate respondsToSelector:@selector(tabBarDidClickPlusButton:)]) {
        [self.tabBarDelegate tabBarDidClickPlusButton:self];
    }
}

7、在WBTabBarController中设置WBTabBar的代理，具体实现如下：

 // 2、使用KVC的方式，更换系统自带的UITabBar
    WBTabBar *tabBar = [[WBTabBar alloc] init];
    tabBar.tabBarDelegate = self;
    [self setValue:tabBar forKeyPath:@"tabBar"];

#pragma mark - HWTabBarDelegate代理方法
- (void)tabBarDidClickPlusButton:(WBTabBar *)tabBar
{
    ComposeViewController *composeViewController= [[ComposeViewController alloc] init];
    UINavigationController * navigationController = [[UINavigationController alloc]initWithRootViewController:composeViewController];
    [self presentViewController:navigationController animated:YES completion:nil];
}

8、有图有真相，已实现的效果图如下：

点击加号按钮，弹出写作界面，效果图如下：

WBTabBarController.m文件完整源码如下：

//
//  WBTabBarController.m
//  SinaWeibo
//
//  Created by android_ls on 15/5/17.
//  Copyright (c) 2015年 android_ls. All rights reserved.
//

#import "WBTabBarController.h"
#import "HomeViewController.h"
#import "MessageViewController.h"
#import "DiscoverViewController.h"
#import "ProfileViewController.h"
#import "WBNavigationController.h"
#import "WBTabBar.h"
#import "ComposeViewController.h"

@interface WBTabBarController ()<WBTabBarDelegate>
{
    HomeViewController * _homeViewController;
    MessageViewController * _messageViewController;
    DiscoverViewController * _discoverViewController;
    ProfileViewController * _profileViewController;
}
@end

@implementation WBTabBarController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    // 初始化子控制器，并将其添加到UITabBarController中
    _homeViewController = [[HomeViewController alloc]init];
    [self addChildController:_homeViewController title:@"首页" image:@"tabbar_home"];
    
    _messageViewController = [[MessageViewController alloc]init];
    [self addChildController:_messageViewController title:@"消息" image:@"tabbar_message_center"];
    
    _discoverViewController = [[DiscoverViewController alloc]init];
    [self addChildController:_discoverViewController title:@"发现" image:@"tabbar_discover"];
    
    _profileViewController = [[ProfileViewController alloc]init];
    [self addChildController:_profileViewController title:@"我" image:@"tabbar_profile"];
    
    // @property(nonatomic,readonly) UITabBar *tabBar NS_AVAILABLE_IOS(3_0);
    // tabBar是UITabBarController的只读成员变量（属性），是不让修改的
    
    // 2、使用KVC的方式，更换系统自带的UITabBar
    WBTabBar *tabBar = [[WBTabBar alloc] init];
    tabBar.tabBarDelegate = self;
    [self setValue:tabBar forKeyPath:@"tabBar"];
    
}

#pragma mark - HWTabBarDelegate代理方法
- (void)tabBarDidClickPlusButton:(WBTabBar *)tabBar
{
    ComposeViewController *composeViewController= [[ComposeViewController alloc] init];
    UINavigationController * navigationController = [[UINavigationController alloc]initWithRootViewController:composeViewController];
    [self presentViewController:navigationController animated:YES completion:nil];
}

/**
 * 添加子控制器到UITabBarController中
 */
- (void)addChildController:(UIViewController *)childViewController title:(NSString *)title image:(NSString *)image
{
    // 设置子控制器，tabbar和navigationBar上的title
    childViewController.title = title;
    
    // 设置tabBarItem上默认的指示图片和选中时的图片
    childViewController.tabBarItem.image = [UIImage imageNamed:image];
    childViewController.tabBarItem.selectedImage = [[UIImage imageNamed:[NSString stringWithFormat:@"%@%@", image, @"_selected"]]imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    
    // 设置tabBarItem上文字的样式（这里是设置文字在不同状态下的颜色值）
    [childViewController.tabBarItem setTitleTextAttributes:
     @{NSForegroundColorAttributeName:kColor(117, 117, 117)} forState:UIControlStateNormal];
    [childViewController.tabBarItem setTitleTextAttributes:
     @{NSForegroundColorAttributeName:kColor(253, 109, 10)} forState:UIControlStateSelected];
    
    // 使用系统默认的UINavigationController
//    [self addChildViewController:[[UINavigationController alloc] initWithRootViewController:childViewController]];
    
    // 使用我们自定义的导航栏(WBNavigationController继承自UINavigationController)
    WBNavigationController * navigationController = [[WBNavigationController alloc]initWithRootViewController:childViewController];
    [self addChildViewController:navigationController];
}

@end

WBTabBar.h文件完整源码如下：

//
//  WBTabBar.h
//  SinaWeibo
//
//  Created by android_ls on 15/5/21.
//  Copyright (c) 2015年 android_ls. All rights reserved.
//

#import <UIKit/UIKit.h>

#pragma mark 因为在UITabBar中已经声明过一个UITabBarDelegate协议，
#pragma mark 我们若想新增一个对外的代理函数，可以让我们自定义的协议继承自UITabBarDelegate，添加一个扩展函数。

@class WBTabBar;

@protocol WBTabBarDelegate <UITabBarDelegate>

@optional
- (void)tabBarDidClickPlusButton:(WBTabBar *)tabBar;

@end

@interface WBTabBar : UITabBar

@property (nonatomic, weak) id<WBTabBarDelegate> tabBarDelegate;

@end

WBTabBar.m文件完整源码如下：

//
//  WBTabBar.m
//  SinaWeibo
//
//  Created by android_ls on 15/5/21.
//  Copyright (c) 2015年 android_ls. All rights reserved.
//

#import "WBTabBar.h"

@interface WBTabBar()
@property (nonatomic, weak) UIButton *plusBtn;
@end

@implementation WBTabBar

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // 添加一个按钮到tabbar中
        UIButton *plusBtn = [[UIButton alloc] init];
        [plusBtn setBackgroundImage:[UIImage imageNamed:@"tabbar_compose_button"] forState:UIControlStateNormal];
        [plusBtn setBackgroundImage:[UIImage imageNamed:@"tabbar_compose_button_highlighted"] forState:UIControlStateHighlighted];
        [plusBtn setImage:[UIImage imageNamed:@"tabbar_compose_background_icon_add"] forState:UIControlStateNormal];
        [plusBtn setImage:[UIImage imageNamed:@"tabbar_compose_icon_add_highlighted"] forState:UIControlStateHighlighted];
        plusBtn.size = plusBtn.currentBackgroundImage.size;
        [plusBtn addTarget:self action:@selector(plusClick) forControlEvents:UIControlEventTouchUpInside];
        [self addSubview:plusBtn];
        self.plusBtn = plusBtn;
    }
    return self;
}

#pragma mark 加号按钮点击事件处理器
- (void)plusClick
{
    // 通知代理
    if ([self.tabBarDelegate respondsToSelector:@selector(tabBarDidClickPlusButton:)]) {
        [self.tabBarDelegate tabBarDidClickPlusButton:self];
    }
}

- (void)layoutSubviews
{
    [super layoutSubviews];
    
    // 1.设置加号按钮的位置
    self.plusBtn.centerX = self.width * 0.5;
    self.plusBtn.centerY = self.height * 0.5;
    
    // 2.设置其它UITabBarButton的位置和尺寸
    CGFloat tabbarButtonW = self.width / 5;
    CGFloat tabbarButtonIndex = 0;
    for (UIView *child in self.subviews) {
        Class class = NSClassFromString(@"UITabBarButton");
        if ([child isKindOfClass:class]) {
            // 设置宽度
            child.width = tabbarButtonW;
            // 设置x
            child.x = tabbarButtonIndex * tabbarButtonW;
            
            // 增加索引
            tabbarButtonIndex++;
            if (tabbarButtonIndex == 2) {
                tabbarButtonIndex++;
            }
        }
    }
}

@end

ComposeViewController继承自UIViewController，主要实现在m文件，其完整代码如下：

//
//  ComposeViewController.m
//  SinaWeibo
//
//  Created by android_ls on 15/5/21.
//  Copyright (c) 2015年 android_ls. All rights reserved.
//

#import "ComposeViewController.h"
#import "UIBarButtonItem+Category.h"

@interface ComposeViewController ()

@end

@implementation ComposeViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.title = @"写作界面";
    self.view.backgroundColor = [UIColor whiteColor];
    
    self.navigationItem.leftBarButtonItem = [UIBarButtonItem itemWithTarget:self
                            action:@selector(back)
                            image:@"navigationbar_back_withtext"
                            highImage:@"navigationbar_back_withtext_highlighted"
                            title:@"返回"];

}

- (void)back
{
    [self.navigationController dismissViewControllerAnimated:YES completion:^{}];
}

@end