ios自动滚动UILabel，跑马灯，有两种滚动方式

短命女 2022-06-09 06:00 462阅读 0赞

主要代码：

KJMarqueeLabel.h

#import <UIKit/UIKit.h>
    
    typedef NS_ENUM(NSUInteger, KJMarqueeLabelType) {
        KJMarqueeLabelTypeLeft = 0,//向左边滚动
        KJMarqueeLabelTypeLeftRight = 1,//先向左边，再向右边滚动
    };
    
    @interface KJMarqueeLabel : UILabel
    @property(nonatomic,unsafe_unretained)KJMarqueeLabelType marqueeLabelType;
    @property(nonatomic,unsafe_unretained)CGFloat speed;//速度
    @property(nonatomic,unsafe_unretained)CGFloat secondLabelInterval;
    @property(nonatomic,unsafe_unretained)NSTimeInterval stopTime;//滚到顶的停止时间
    
    @end

KJMarqueeLabel.m

#import "KJMarqueeLabel.h"
    
    @interface KJMarqueeLabel ()<UIScrollViewDelegate>{
        NSTimer *_timer;
        UIScrollView *_scrollV;
        UILabel *_label1;
        CGSize _scrollViewCcontentSize;
        CGFloat x;
        UILabel *_label2;
        BOOL _isRight;
    }
    @end
    
    @implementation KJMarqueeLabel
    
    - (void)awakeFromNib {
        [super awakeFromNib];
        [self commonInit];
    }
    
    -(instancetype)init {
        if (self = [super init]) {
            [self commonInit];
        }
        return self;
    }
    
    - (instancetype)initWithCoder:(NSCoder *)coder
    {
        self = [super initWithCoder:coder];
        if (self) {
            [self commonInit];
        }
        return self;
    }
    
    -(instancetype)initWithFrame:(CGRect)frame {
        self = [super initWithFrame:frame];
        if (self) {
            [self commonInit];
        }
        return self;
    }
    
    -(void)commonInit{
        self.marqueeLabelType = KJMarqueeLabelTypeLeftRight;
        self.secondLabelInterval = 100;
        self.speed = 0.7f;
        self.stopTime = 1.5f;
    }
    
    -(UILabel *)comnInitLabel:(UILabel *)label {
        label = [[UILabel alloc]initWithFrame:self.bounds];
        label.text = self.text;
        label.font = self.font;
        label.textColor = self.textColor;
        label.lineBreakMode = NSLineBreakByWordWrapping;
        return label;
    }
    
    -(void)drawTextInRect:(CGRect)rect {
        for (UIView *view in self.subviews) {
            [view removeFromSuperview];
        }
        CGFloat height = self.bounds.size.height;
        CGFloat width = self.bounds.size.width;
        
        x = 0;
        _label1 = [self comnInitLabel:_label1];
        if (self.marqueeLabelType == KJMarqueeLabelTypeLeft) {
            _label2 = [self comnInitLabel:_label2];
        }
        
        CGSize size = [_label1 sizeThatFits:CGSizeMake(MAXFLOAT,height)];
        
        //如果字符串的宽度小于或等于自身的宽度
        if (size.width <= width) {
            _label1 = nil;
            _label2 = nil;
            [super drawTextInRect:rect];
            return;
        }
        
        _scrollV = [[UIScrollView alloc]initWithFrame:self.bounds];
        _scrollV.delegate = self;
        if (self.marqueeLabelType == KJMarqueeLabelTypeLeft) {
            _scrollViewCcontentSize = CGSizeMake(size.width+width+self.secondLabelInterval, size.height);
        }else {
            _scrollViewCcontentSize = CGSizeMake(size.width, size.height);
        }
        _scrollV.contentSize = _scrollViewCcontentSize;
        
        [self addSubview:_scrollV];
        
        CGRect rect1 =  _label1.frame;
        rect1.size.width = size.width;
        _label1.frame = rect1;
        [_scrollV addSubview:_label1];
        
        if (self.marqueeLabelType == KJMarqueeLabelTypeLeft) {
            CGRect rect2 =  _label2.frame;
            rect2.size.width = width;
            rect2.origin.x = size.width + self.secondLabelInterval;
            _label2.frame = rect2;
            [_scrollV addSubview:_label2];
        }
        
        [self Timer];
    }
    
    - (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView {
        if (_timer) {
            [_timer invalidate];
            _timer = nil;
        }
    }
    
    - (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate {
        x = scrollView.contentOffset.x;
        [self Timer];
    }
    
    -(void)Timer {
        if (_timer) {
            [_timer invalidate];
            _timer = nil;
        }
    
        _timer = [NSTimer scheduledTimerWithTimeInterval:0.01f target:self selector:@selector(refreshMarqueeLabelFrame) userInfo:nil repeats:YES];
        [[NSRunLoop currentRunLoop] addTimer:_timer forMode:NSRunLoopCommonModes];
    }
    
    -(void)FistTimer {
        if (_timer) {
            [_timer invalidate];
            _timer = nil;
        }
        _timer = [NSTimer scheduledTimerWithTimeInterval:self.stopTime target:self selector:@selector(delayMethod) userInfo:nil repeats:NO];
    }
    
    -(void)dealloc {
        if (_timer) {
            [_timer invalidate];
            _timer = nil;
        }
    }
    
    -(void)delayMethod {
        [self Timer];
    }
    
    - (void)refreshMarqueeLabelFrame {
        
        if (self.marqueeLabelType == KJMarqueeLabelTypeLeft) {
            
            x += self.speed;
            if (x > _scrollViewCcontentSize.width - _scrollV.bounds.size.width) {
                [self FistTimer];
                x = 0;
            }
            [_scrollV setContentOffset:CGPointMake(x, 0)];
            
        }else {
            if (_isRight) {
                x -= self.speed;
            }else {
                x += self.speed;
            }
            
            if (x > _scrollViewCcontentSize.width - _scrollV.bounds.size.width) {
                [self FistTimer];
                _isRight = YES;
                return;
            }
            
            if (x <= 0) {
                [self FistTimer];
                _isRight = NO;
            }
            
            [_scrollV setContentOffset:CGPointMake(x, 0)];
        }
    }
    
    @end

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