下面是效果图：
效果图
要实现上面的效果方法有好多种，今天我们用原生的UITabBar来做。
注：这里有一个很小的知识点需要注意一下就是UITabBarItem 是UIBarItem 的子类，直接继承自其。理解这个有助于更好的理解具体实现。
其实实现起来的大致步骤为：
一、item突出显示（偏移）
二、item手势响应处理
item突出显示（偏移）
第一步很简单。创建一个UITabBarController并添加子控制器。
.h
@interface TabbarVC : UITabBarController
@end
.m
-(void)addControllers{
OneVC *one = [[OneVC alloc]init];
UINavigationController *navOne = [[UINavigationController alloc]initWithRootViewController:one];
navOne.tabBarItem = [self getTabBarItemWithTitle:@"第一个" image:[UIImage imageNamed:@"动态"] selectImage:[UIImage imageNamed:@"动态hober"] tag:1];
TwoVC *two = [[TwoVC alloc]init];
UINavigationController *navTwo = [[UINavigationController alloc]initWithRootViewController:two];
navTwo.tabBarItem = [self getTabBarItemWithTitle:@"第二个" image:[UIImage imageNamed:@"我的"] selectImage:[UIImage imageNamed:@"我的hover"] tag:2];
ThreeVC *three = [[ThreeVC alloc]init];
UINavigationController *navThree = [[UINavigationController alloc]initWithRootViewController:three];
navThree.tabBarItem = [self getTabBarItemWithTitle:@"第三个" image:[UIImage imageNamed:@"展示"] selectImage:[UIImage imageNamed:@"展示hover"] tag:3];
FourVC *four = [[FourVC alloc]init];
UINavigationController *navFour = [[UINavigationController alloc]initWithRootViewController:four];
navFour.tabBarItem = [self getTabBarItemWithTitle:@"第四个" image:[UIImage imageNamed:@"训练"] selectImage:[UIImage imageNamed:@"训练hover"] tag:4];
FiveVC *five = [[FiveVC alloc]init];
UINavigationController *navFive = [[UINavigationController alloc]initWithRootViewController:five];
navFive.tabBarItem = [self getTabBarItemWithTitle:@"第四个" image:[UIImage imageNamed:@"收藏灰"] selectImage:[UIImage imageNamed:@"收藏"] tag:5];
self.viewControllers = @[navOne,navTwo,navThree,navFour,navFive];
}
-(UITabBarItem *)getTabBarItemWithTitle:(NSString *)title image:(UIImage *)image selectImage:(UIImage *)selectImage tag:(NSInteger)tag{
UITabBarItem *item = [[UITabBarItem alloc]initWithTitle:title image:image tag:tag];
item.selectedImage = selectImage;
return item;
}
紧接着我们实现UITabBarController 的viewWillLayoutSubviews方法，获取到自己的tabBar上的指定UITabBarItem ，然后拿到UITabBarItem上的imageView视图，设置偏移量，并添加点击事件，做出响应事件的处理。
-(void)viewWillLayoutSubviews{
[super viewWillLayoutSubviews];
UITabBarItem *tabbarItem = self.tabBar.items[2];
tabbarItem.imageInsets = UIEdgeInsetsMake(-25, 0, 0, 0);
UIImageView *imageView = [tabbarItem lgj_imageView];
if (imageView && !imageView.userInteractionEnabled) {
imageView.userInteractionEnabled = YES;
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(mittileTap)];
[imageView addGestureRecognizer:tap];
}
}
-(void)mittileTap{
self.selectedIndex = 2;
}
item手势响应处理
接下来创建UIBarItem、UITabBarItem和UITabBar的分类
UIBarItem+LGJBarItem.h
#import <UIKit/UIKit.h>
@interface UIBarItem (LGJBarItem)
@property(nonatomic,nullable,weak,readonly)UIView *lgj_view;
@end
#import "UIBarItem+LGJBarItem.h"
@implementation UIBarItem (LGJBarItem)
-(UIView *)lgj_view{
return [self valueForKey:@"view"];
}
@end
UITabBarItem+LGJBarItem.h
#import <UIKit/UIKit.h>
@interface UITabBarItem (LGJTabBarItem)
@property(nonatomic, copy) void (^lgj_doubleTapBlock)(UITabBarItem *tabBarItem, NSInteger index);
- (UIImageView *)lgj_imageView;
+ (UIImageView *)lgj_imageViewInTabBarButton:(UIView *)tabBarButton;
@end
#import "UITabBarItem+LGJTabBarItem.h"
#import "UIBarItem+LGJBarItem.h"
#import <objc/runtime.h>
@implementation UITabBarItem (LGJTabBarItem)
- (UIImageView *)lgj_imageView {
return [self.class lgj_imageViewInTabBarButton:self.lgj_view];
}
+ (UIImageView *)lgj_imageViewInTabBarButton:(UIView *)tabBarButton {
if (!tabBarButton ) {
return nil;
}
for (UIView *subView in tabBarButton.subviews) {
if ([NSStringFromClass([subView class]) isEqualToString:@"UITabBarSwappableImageView"]) {
return (UIImageView *)subView;
}
NSDictionary *infoDictionary = [[NSBundle mainBundle] infoDictionary];
CFShow(CFBridgingRetain(infoDictionary));
NSString *app_Version = [infoDictionary objectForKey:@"CFBundleShortVersionString"];
float version = [app_Version floatValue];
if (version < 10) {
// iOS10以前，选中的item的高亮是用UITabBarSelectionIndicatorView实现的，所以要屏蔽掉
if ([subView isKindOfClass:[UIImageView class]] && ![NSStringFromClass([subView class]) isEqualToString:@"UITabBarSelectionIndicatorView"]) {
return (UIImageView *)subView;
}
}
}
return nil;
}
static char kAssociatedObjectKey_doubleTapBlock;
- (void)setLgj_doubleTapBlock:(void (^)(UITabBarItem *, NSInteger))gs_doubleTapBlock {
objc_setAssociatedObject(self, &kAssociatedObjectKey_doubleTapBlock, gs_doubleTapBlock, OBJC_ASSOCIATION_COPY_NONATOMIC);
}
- (void (^)(UITabBarItem *, NSInteger))lgj_doubleTapBlock {
return (void (^)(UITabBarItem *, NSInteger))objc_getAssociatedObject(self, &kAssociatedObjectKey_doubleTapBlock);
}
@end
UITabBar+LGJBarItem.h
#import <UIKit/UIKit.h>
@interface UITabBar (LGJTabBar)
@end
#import "UITabBar+LGJTabBar.h"
#import "UITabBarItem+LGJTabBarItem.h"
@implementation UITabBar (LGJTabBar)
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
if (!self.isUserInteractionEnabled || self.isHidden || self.alpha <= 0.01) {
return nil;
}
if (self.items.count < 2) {
return [super hitTest:point withEvent:event];
}
UITabBarItem *item = self.items[2];
UIImageView *itemImageView = [item lgj_imageView];
if (!itemImageView) {
return [super hitTest:point withEvent:event];
}
UIView *view = [super hitTest:point withEvent:event];
if (view == nil){
//转换坐标
CGPoint tempPoint = [itemImageView convertPoint:point fromView:self];
//判断点击的点是否在按钮区域内
if (CGRectContainsPoint(itemImageView.bounds, tempPoint)){ //返回按钮
return itemImageView;
}
//****************** 或者使用这个方法 ****************
//判断如果这个新的点是在发布按钮身上，那么处理点击事件最合适的view就是发布按钮
if ([itemImageView pointInside:point withEvent:event]) {
return itemImageView;
}else{
//如果点不在发布按钮身上，直接让系统处理就可以了
return [super hitTest:point withEvent:event];
}
}
return view;
}
@end
以上工作完成，一个突出的TabBar就出现了，，，，
