iOS实战之使用View实现导航栏下的滑动菜单

正文

菜单滚动视图也是在项目开发过程中比较常用到的功能，先直接看效果图

实现的效果如下： 当菜单个数的总长度超过一个屏宽度就计算每一个的文字宽度，若没有则只进行一个屏平分，点击菜单项时，滚动的视图位置会随着调整；下面将会把代码贴出来； 1：控制器.h文件的内容

#import <UIKit/UIKit.h>

@protocol myScrollTabBarDelegate <NSObject>

@optional

- (void)itemDidSelectedWithIndex:(NSInteger)index;

@end

@interface myScrollerViewController : UIViewController

@property (nonatomic, weak) id  <myScrollTabBarDelegate>delegate;
@property (nonatomic, assign) NSInteger currentIndex;
@property(nonatomic,copy)NSArray *myTitleArray;
@end

注意：这边创建的一个delegate，主要是为了当点击事件时把相应的动作往外传，并把相应的菜单索引值传出，方便做其它操作 2：.m控制器的内容

#import "myScrollerViewController.h"

#define SCREEN_WIDTH  ([UIScreen mainScreen].bounds.size.width)
#define SCREEN_HEIGHT ([UIScreen mainScreen].bounds.size.height)
#define TABBAR_TITLE_FONT [UIFont systemFontOfSize:18.f]
#define NAV_TAB_BAR_HEIGHT 50
#define NAV_TAB_BAR_Width  SCREEN_WIDTH

@interface myScrollerViewController ()
//滚动视图
@property(strong,nonatomic)UIScrollView *myScrollView;
//滚动下划线
@property(strong,nonatomic)UIView *line;
//所有的Button集合
@property(nonatomic,strong)NSMutableArray  *items;
//所有的Button的宽度集合
@property(nonatomic,copy)NSArray *itemsWidth;
//被选中前面的宽度合（用于计算是否进行超过一屏，没有一屏则进行平分）
@property(nonatomic,assign)CGFloat selectedTitlesWidth;

@end

@implementation myScrollerViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    self.automaticallyAdjustsScrollViewInsets=NO;
    
    self.view.backgroundColor=[UIColor whiteColor];
    
    //初始化数组
    if (!self.myTitleArray) {
        self.myTitleArray=@[@"新闻",@"NBA",@"财经",@"科技",@"软件公司",@"健身",@"优秀文摘"];
    }
    
    self.items=[[NSMutableArray alloc]init];
    self.itemsWidth=[[NSArray alloc]init];
    
    //初始化滚动
    if (!self.myScrollView) {
        self.myScrollView=[[UIScrollView alloc]initWithFrame:CGRectMake(0, 64, NAV_TAB_BAR_Width, NAV_TAB_BAR_HEIGHT)];
        self.myScrollView.backgroundColor=[UIColor redColor];
        self.myScrollView.showsHorizontalScrollIndicator = NO;
        self.myScrollView.showsVerticalScrollIndicator = NO;
        [self.view addSubview:self.myScrollView];
    }
    
    //赋值跟计算滚动
    _itemsWidth = [self getButtonsWidthWithTitles:self.myTitleArray];
    CGFloat contentWidth = [self contentWidthAndAddNavTabBarItemsWithButtonsWidth:_itemsWidth];
    self.myScrollView.contentSize = CGSizeMake(contentWidth, 0);
    
    self.currentIndex=0;
}

/**
 *  @brief  计算宽度
 *
 *  @param titles <#titles description#>
 *
 *  @return <#return value description#>
 */
- (NSArray *)getButtonsWidthWithTitles:(NSArray *)titles;
{
    NSMutableArray *widths = [@[] mutableCopy];
    _selectedTitlesWidth = 0;
    for (NSString *title in titles)
    {
        CGSize size = [title boundingRectWithSize:CGSizeMake(CGFLOAT_MAX, CGFLOAT_MAX) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName : TABBAR_TITLE_FONT} context:nil].size;
        CGFloat eachButtonWidth = size.width + 20.f;
        _selectedTitlesWidth += eachButtonWidth;
        NSNumber *width = [NSNumber numberWithFloat:eachButtonWidth];
        [widths addObject:width];
    }
    if (_selectedTitlesWidth < NAV_TAB_BAR_Width) {
        [widths removeAllObjects];
        NSNumber *width = [NSNumber numberWithFloat:NAV_TAB_BAR_Width / titles.count];
        for (int index = 0; index < titles.count; index++) {
            [widths addObject:width];
        }
    }
    return widths;
}
/**
 *  @brief  初始化Button
 *
 *  @param widths <#widths description#>
 *
 *  @return <#return value description#>
 */
- (CGFloat)contentWidthAndAddNavTabBarItemsWithButtonsWidth:(NSArray *)widths
{
    CGFloat buttonX = 0;
    for (NSInteger index = 0; index < widths.count; index++)
    {
        UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
        button.frame = CGRectMake(buttonX, 0, [widths[index] floatValue], NAV_TAB_BAR_HEIGHT);
        button.titleLabel.font = TABBAR_TITLE_FONT;
        button.backgroundColor = [UIColor clearColor];
        [button set

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