前言

大多情況下，我們使用系統的tabbar基本上可以滿足產品的需求，但是有時候產品不按套路出牌，比如說類似於微部落格戶端一樣，在tabbar中間增加一個”＋”號按鈕，那我們就需要自定了，其實也比較簡單。

一、自定義一個UITabBar

1、新建一個類，繼承UITabBar，我取的類名叫做：HSTabBar.

2、在HSTabBar.h中新增如下程式碼：

#import <UIKit/UIKit.h>

@class HSTabBar;

@protocol HSTabBarDelegate <UITabBarDelegate>

@optional

- (void
 
)tabBarDidClickPlusButton:(HSTabBar *)tabBar;

@end

@interface HSTabBar : UITabBar

@property (nonatomic, strong) UIButton *plusBtn;
@property (nonatomic, weak) id <HSTabBarDelegate> tabBarDelegate;

@end

3、在HSTabBar.m中新增如下程式碼：

#import "HSTabBar.h"

@implementation HSTabBar

- (id)initWithFrame:(CGRect
 
)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // 新增一個按鈕到tabbar中
        UIButton *plusBtn = [[UIButton alloc] init];
        [plusBtn setImage:[UIImage imageNamed:@"icon_bottom_add"] forState:UIControlStateNormal];
        CGRect temp = plusBtn.frame;
        temp.size=plusBtn.currentImage
 
.size;
        plusBtn.frame=temp;
        [plusBtn addTarget:self action:@selector(plusClick) forControlEvents:UIControlEventTouchUpInside];
        [self addSubview:plusBtn];
        self.plusBtn = plusBtn;
    }
    return self;
}

- (void)plusClick
{
    // 通知代理
    if ([self.tabBarDelegate respondsToSelector:@selector(tabBarDidClickPlusButton:)]) {
        [self.tabBarDelegate tabBarDidClickPlusButton:self];
    }
}

- (void)layoutSubviews
{
    [super layoutSubviews];

    // 1.設定加號按鈕的位置
    CGPoint temp = self.plusBtn.center;
    temp.x=self.frame.size.width/2;
    temp.y=self.frame.size.height/2;
    self.plusBtn.center=temp;

    // 2.設定其它UITabBarButton的位置和尺寸
    CGFloat tabbarButtonW = self.frame.size.width / 5;
    CGFloat tabbarButtonIndex = 0;
    for (UIView *child in self.subviews) {
        Class class = NSClassFromString(@"UITabBarButton");
        if ([child isKindOfClass:class]) {
            // 設定寬度
            CGRect temp1=child.frame;
            temp1.size.width=tabbarButtonW;
            temp1.origin.x=tabbarButtonIndex * tabbarButtonW;
            child.frame=temp1;
            // 增加索引
            tabbarButtonIndex++;
            if (tabbarButtonIndex == 2) {
                tabbarButtonIndex++;
            }
        }
    }
}

@end

二、HSTabBar的使用

1、新建一個類，繼承UITabbarViewControll, 類名命名為：RootTabBarController.

2、匯入HSTabBar的標頭檔案

#import "HSTabBar.h"

3、在RootTabBarController 中的 viewDidLoad方法中新增程式碼：

  HSTabBar *tabBar = [[HSTabBar alloc] init];
  tabBar.tabBarDelegate = self;
  [self setValue:tabBar forKeyPath:@"tabBar"];

其他的一些建立導航控制器和將控制器加入tabBar中的程式碼此處省略了，自己去吧。

4、實現HSTabBarDelegate代理方法

#pragma mark - HSTabBarDelegate代理方法
- (void)tabBarDidClickPlusButton:(HSTabBar *)tabBar
{
    _bgView = [UICommonCtrl commonViewWithFrame:CGRectMake(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT) color:kColor_Transparent];
    [kAppDelegate.window addSubview:_bgView];

    UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapGesture:)];
    [_bgView addGestureRecognizer:tapGesture];


    NSArray *arrData = @[@{@"title":@"簽到",@"image":@"icon_add_sign"},
                         @{@"title":@"發起群聊",@"image":@"icon_add_group"},
                         @{@"title":@"申請",@"image":@"icon_add_apply"},
                         @{@"title":@"建立專案",@"image":@"icon_add_project"},
                         @{@"title":@"建立任務",@"image":@"icon_add_task"},
                         @{@"title":@"會議預定",@"image":@"icon_add_boardroom"}];

    UIView *baseView = [UICommonCtrl commonViewWithFrame:CGRectMake(0, SCREEN_HEIGHT-200, SCREEN_WIDTH, 200) color:kColor_White];
    [_bgView addSubview:baseView];

    float spaceWidth = (SCREEN_WIDTH-60*3)/6;

    for (NSInteger i=0; i<arrData.count; i++) {

        NSInteger x = i % 3;
        NSInteger y = i / 3;

        UIButton *btn = [UICommonCtrl commonCenterControlButtonWithFrame:CGRectMake(spaceWidth+(spaceWidth*2+60)*x, 20+y*100, 60, 60)
                                                                    text:[[arrData objectAtIndex:i] objectForKey:@"title"]
                                                                   color:kColor_Black
                                                                    font:kFont_Middle
                                                                   image:[UIImage imageNamed:[[arrData objectAtIndex:i]objectForKey:@"image"]]
                                                                 spacing:5.0
                                                                  target:self
                                                                  action:@selector(btnClick:)];
        [btn setTag:i];
        [baseView addSubview:btn];

    }

}

- (void)btnClick:(UIButton *)btn
{
    if (btn.tag == 0) {

    } else if (btn.tag  == 1) {

    } else if (btn.tag  == 2) {

    } else if (btn.tag  == 3) {

    } else if (btn.tag  == 4) {

    } else {

    }
    [_bgView removeFromSuperview];
}

- (void)tapGesture:(UITapGestureRecognizer *)tapGesture
{
    [_bgView removeFromSuperview];
}

根據自己的需求新增或修改相應的程式碼。

效果圖