循环滚动展示 label 业务需要做了一个上下滚动展示的文字广告位，类似轮播图的效果
Github 上的 Demo
用两个UILabel循环滚动，在UIView动画执行完成后，设置 frame，并且再次调用UIView的动画 没有用NSTimer简化了很多防止内存泄露的地方 贴出一部分代码（没有加注释，逻辑一般看看能明白）
- (void)startAnimation {_stopAnimate = NO;if (![self isCurrentViewControllerVisible:[self viewController]]) { // 处于非当前页面// 防止上一次动画没有完成，会一直加载两次动画，所以延迟一下执行[self performSelector:@selector(startAnimation) withObject:nil afterDelay:0.1];}else{__weak typeof(self) weakSelf = self;[UIView animateWithDuration:1.0 delay:_timeInterVal options:0 animations:^{if (!_wichOne) {_label_0.frame = CGRectMake(0, -self.frame.size.height, _label_0.frame.size.width, _label_0.frame.size.height);_label_1.frame = CGRectMake(0, 0, _label_1.frame.size.width, _label_1.frame.size.height);}else {_label_0.frame = CGRectMake(0, 0, _label_0.frame.size.width, _label_0.frame.size.height);_label_1.frame = CGRectMake(0, -self.frame.size.height, _label_1.frame.size.width, _label_1.frame.size.height);}} completion:^(BOOL finished) {if (!_stopAnimate) {_wichOne = !_wichOne;_showCount++;if (_showCount > _textArray.count - 1) {_showCount = 0;}if (_label_0.frame.origin.y == -self.frame.size.height) {_label_0.frame = CGRectMake(0, self.frame.size.height, _label_0.frame.size.width, _label_0.frame.size.height);_label_0.text = _textArray[_showCount];_label_0.tag = _showCount;}if (_label_1.frame.origin.y == -self.frame.size.height) {_label_1.frame = CGRectMake(0, self.frame.size.height, _label_1.frame.size.width, _label_1.frame.size.height);_label_1.text = _textArray[_showCount];_label_1.tag = _showCount;}[weakSelf startAnimation];}}];}
}
复制代码
