iOS - 实现在有限label上动态显示所有文字

约定不等于承诺〃 2021-12-21 05:39 239阅读 0赞

效果如下:

[![image][]][image 1]

### [点击下载查看demo][demo] ###

### 思路 ###

### (1)创建一个view 作为所有内容的父控件, 并且添加到上面一个 label, 作为显示文字的载体 ###

UILabel* contentLabel = [[UILabel alloc] init];
    [contentLabel sizeToFit];

contentLabel.backgroundColor = \[UIColor clearColor\]; \_contentLabel = contentLabel; \[self addSubview:self.contentLabel\];

### (2)给内容view的layer添加一个mask层, 并且设置其范围为整个view的bounds, 这样就让超出view的内容不会显示出来 ###

CAShapeLayer* maskLayer = [CAShapeLayer layer];
    maskLayer.path = [UIBezierPath bezierPathWithRect:self.bounds].CGPath;
    self.layer.mask = maskLayer;

### (3)给label添加动画 ###

CAKeyframeAnimation* keyFrame = [CAKeyframeAnimation animation];
    keyFrame.keyPath = @"transform.translation.x";
    keyFrame.values = @[@(0), @(-space), @(0)];
    keyFrame.repeatCount = NSIntegerMax;
    keyFrame.duration = self.speed * self.contentLabel.text.length;
    keyFrame.timingFunctions = @[[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut], [CAMediaTimingFunction functionWithControlPoints:0 :0 :0.5 :0.5]];
    keyFrame.delegate = self;
    
    [self.contentLabel.layer addAnimation:keyFrame forKey:nil];

## 使用方法 ##

// 创建
    CFDynamicLabel* testLabel = [[CFDynamicLabel alloc] initWithFrame:CGRectMake(100, 300, 180, 21)];
    // 设置滚动速度
    testLabel.speed = 0.6;
    [self.view addSubview:testLabel];
    // 设置基本属性
    testLabel.text = @"我不想说再见,不说再见,越长大越孤单";
    testLabel.textColor = [UIColor yellowColor];
    testLabel.font = [UIFont systemFontOfSize:23];
    testLabel.backgroundColor = [UIColor grayColor];

转载于:https://www.cnblogs.com/yuchuanfeng/p/4760422.html

[image]: https://github.com/yuchuanfeng/CFDynamicLabel/raw/master/001.gif
[image 1]: https://github.com/yuchuanfeng/CFDynamicLabel/blob/master/001.gif
[demo]: https://github.com/yuchuanfeng/CFDynamicLabel