类似京东快报文字跑马灯效果

商城类App基本都会需要这种跑马灯(上下切换效果),这里简易实现了一下。

主要代码

//
//  PZScrollLabel.m
//  跑马灯
//
//  Created by peng on 2018/5/22.
//  Copyright © 2018年 peng. All rights reserved.
//

#import "PZScrollLabel.h"

@interface PZScrollLabel ()
@property (nonatomic, strong)NSArray      *contenArray;
@property (nonatomic, strong)NSTimer      *scrollTimer;
@property (nonatomic, assign)NSInteger     index;
@property (nonatomic, strong)UILabel      *upLabel;
@property (nonatomic, strong)UILabel      *downLabel;
@property (nonatomic, assign)CGFloat       height;
@end
@implementation PZScrollLabel

- (instancetype)initWithFrame:(CGRect)frame WithContens:(NSArray *)contentArr
{
    if(self = [super initWithFrame:frame])
    {
        self.contentSize = CGSizeMake(frame.origin.x, frame.size.height*contentArr.count);
        self.pagingEnabled = YES;
        self.contenArray = contentArr;
        self.index = 0;
        self.height = frame.size.height;
        [self addSubview:self.upLabel];
        [self addSubview:self.downLabel];
        //开启定时器 自动滚动
        [[NSRunLoop  currentRunLoop] addTimer:self.scrollTimer forMode:NSRunLoopCommonModes];
        //添加点击手势
        UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapScrollLabelAction:)];
        [self addGestureRecognizer:tap];
    }
    return self;
}
#pragma mark --  Method
- (void)scrollTimerBegin
{
    [[NSRunLoop  currentRunLoop] addTimer:self.scrollTimer forMode:NSRunLoopCommonModes];
}
//选择某个文字进行操作  利用block传递选择了某个
- (void)tapScrollLabelAction:(UITapGestureRecognizer *)tap
{
    [self.scrollTimer invalidate];
    self.scrollTimer = nil;
    if(self.selectScrollLabel)
    {
        self.selectScrollLabel(self.index);
    }
}
//定时器操作  10.0以下
- (void)scrollTimerAction
{
    self.index ++;
    if(self.index >= self.contenArray.count)
    {
        self.index = 0;
    }
    [UIView transitionWithView:self.upLabel duration:0.5 options:UIViewAnimationOptionCurveEaseInOut animations:^{
        CGRect upFrame = self.upLabel.frame;
        upFrame.origin.y = -self.height;
        self.upLabel.frame = upFrame;
        CGRect downFrame = self.downLabel.frame;
        downFrame.origin.y = 0;
        self.downLabel.frame = downFrame;
        [self.downLabel setText:self.contenArray[self.index]];
        
    } completion:^(BOOL finished) {
        CGRect upFrame = self.upLabel.frame;
        upFrame.origin.y = self.height;
        self.upLabel.frame = upFrame;
        UILabel *tempLabel = self.upLabel;
        self.upLabel = self.downLabel;
        self.downLabel = tempLabel;
    }];
}
- (UILabel *)upLabel
{
    if(_upLabel == nil)
    {
        _upLabel = [[UILabel alloc]initWithFrame:CGRectMake(0, 0, self.frame.size.width, self.height)];
        [_upLabel setText:self.contenArray[self.index]];
    }
    return _upLabel;
}
- (UILabel *)downLabel
{
    if(_downLabel == nil)
    {
        _downLabel = [[UILabel alloc]initWithFrame:CGRectMake(0, self.frame.size.height, self.frame.size.width, self.height)];
    }
    return _downLabel;
}
- (NSTimer *)scrollTimer
{
    if(_scrollTimer == nil)
    {
        
        if (@available(iOS 10.0, *)) {
            _scrollTimer = [NSTimer scheduledTimerWithTimeInterval:2.0 repeats:YES block:^(NSTimer * _Nonnull timer) {
                self.index ++;
                if(self.index >= self.contenArray.count)
                {
                    self.index = 0;
                }
                [UIView transitionWithView:self.upLabel duration:0.5 options:UIViewAnimationOptionCurveEaseInOut animations:^{
                    CGRect upFrame = self.upLabel.frame;
                    upFrame.origin.y = -self.height;
                    self.upLabel.frame = upFrame;
                    CGRect downFrame = self.downLabel.frame;
                    downFrame.origin.y = 0;
                    self.downLabel.frame = downFrame;
                    [self.downLabel setText:self.contenArray[self.index]];
                    
                } completion:^(BOOL finished) {
                    CGRect upFrame = self.upLabel.frame;
                    upFrame.origin.y = self.height;
                    self.upLabel.frame = upFrame;
                    UILabel *tempLabel = self.upLabel;
                    self.upLabel = self.downLabel;
                    self.downLabel = tempLabel;
                }];
            }];
        } else {
            _scrollTimer = [NSTimer scheduledTimerWithTimeInterval:1.5 target:self selector:@selector(scrollTimerAction) userInfo:nil repeats:YES];
        }
    }
    return _scrollTimer;
}
@end

#import 

typedef void(^selectScrollLabelBlock)(NSInteger);

@interface PZScrollLabel : UIScrollView
//copy 修饰block  使其在堆上 可以在作用域外访问
@property (nonatomic, copy)selectScrollLabelBlock selectScrollLabel;
- (instancetype)initWithFrame:(CGRect)frame WithContens:(NSArray *)contentArr;
@end

注：使用的时候只需要传入我们要显示内容数组即可。