iOS开发 - 广播(跑马灯)的实现

1.修改frame
实现思路:

CAKeyframeAnimation
重点: 给主view.layer添加keyframeAnimation动画

Snip20160123_1.png

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实现效果:

Untitled.gif

1.gif

1.首先自定义一个view继承自view用来盛放子控件

@interface ZHXLabel : UIView/** <#name#> *///喇叭图片@property (strong, nonatomic)UIImage *image;//文字@property (nonatomic, strong) NSString *text;//动画播放速度:使用枚举@property (nonatomic, assign) ZHXSpeed speed;// 循环滚动次数(为0时无限滚动)@property (nonatomic, assign) NSUInteger repeatCount;//占位控件@property (nonatomic, strong) UIView *viewGap;//添加子控件方法- (void)reloadView;@end

2..m中的实现

//用代码初始化- (instancetype)initWithFrame:(CGRect)frame{    if (self = [super initWithFrame:frame]) {        self.font = [UIFont systemFontOfSize:15];        self.speed = ZHXSpeedMild;        self.repeatCount = 0;//超出主view部分剪切.        self.clipsToBounds = YES;        [self setup];    }    return self;}

主要实现方法

//创建view- (void)reloadView{    //删除内部view.layer的动画    [self.innerContainer.layer removeAnimationForKey:@"move"];    CGFloat width1 = 0.f;    NSDictionary *attr = @{NSFontAttributeName : self.font};    // 新方法 : boundingRectWithSize 计算文本bounds (CGFLOAT_MAX 宽度范围是不确定的所以要用MAX.)这个方法返回任意NSString的size.widht.    CGSize size = [self.text boundingRectWithSize:CGSizeMake(CGFLOAT_MAX, self.bounds.size.height) options:0 attributes:attr context:nil].size;    width1 = size.width;    CGFloat width = width1;    //如果文本width大于view的width 就移动    moveNeed = width > self.bounds.size.width;    //设置label的fram    CGRect f = CGRectMake(0, 0, width, self.bounds.size.height);    /*---------------------------*/    //创建label-1    UILabel *label = [[UILabel alloc] initWithFrame:f];    label.backgroundColor = [UIColor whiteColor];        //设置label文字.        label.text = self.text;    //将label添加到内部view空间中.    [self.innerContainer addSubview:label];    /*---------------------------*/    //如果需要移动.    if (moveNeed) {    /*---------------------------*/        //创建间隔view        self.viewGap = [[UIView alloc] initWithFrame:CGRectMake(CGRectGetMaxX(label.frame), 0, 50, self.bounds.size.height)];        self.viewGap.backgroundColor = [UIColor whiteColor];        self.backgroundColor = [UIColor whiteColor];        [self addSubview:self.viewGap];        //viewGap 文字段落间隔. 创建下一个label 用来循环移动.        CGRect f1 = CGRectMake(width + self.viewGap.bounds.size.width, 0, width, f.size.height);    /*---------------------------*///创建label-2        UILabel *next = [[UILabel alloc] initWithFrame:f1];        self.backgroundColor = [UIColor whiteColor];        next.backgroundColor = [UIColor whiteColor];        if (self.text) {            next.text = self.text;            next.textColor = self.textColor;            next.font = self.font;        } else {            next.attributedText = self.attributedText;        }        [self.innerContainer addSubview:next];        //动画 - > 改变x        CAKeyframeAnimation *moveAnimation = [CAKeyframeAnimation animationWithKeyPath:@"transform.translation.x"];        //关键帧.动画对象在指定时间内依次执行关键帧.//具体就是 动画从0这个位置 执行到 x位置![Snip20160123_3.png](http://upload-images.jianshu.io/upload_images/1240886-2d910edbbd4c91e9.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)//从x=0开始,执行到x=0(需求:停顿一下) 再从x = 0 执行到最后.        moveAnimation.values = @[@0,@0 ,@( - width - self.viewGap.bounds.size.width)];//keyTimes对应执行上面的values属性,x = 0到x = 0 执行了总时间的0.1(因为keyTimes与values是一一对应的)达到停顿效果,x = 0 到最后可以自定义.        moveAnimation.keyTimes = @[@0, @0.100, @0.868, @1.0];        //动画持续总时间. rate是自定义的.width相当于主空间的view        moveAnimation.duration = width / rate;        moveAnimation.repeatCount = self.repeatCount == 0 ? INT16_MAX : self.repeatCount;        [self.innerContainer.layer addAnimation:moveAnimation forKey:@"move"];    }}

动画部分详解:

Snip20160123_3.png