修复textView换行不居中的系统bug

有时,我们会有这样的需求,在使用UITextView作为输入框时,输入框换行需要输入框自适应变大,但在此过程中,文字经常不居中,如下图

QQ20160107-0.png

处理方法:
设置textView的代理,在textView换行滚动时强行将文字居中,代码如下

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
  if ([scrollView isKindOfClass:[UITextView class]]) {
        if ( scrollView.contentSize.height <= 200) {// 200  为textView的最大高度
            scrollView.contentOffset = CGPointZero;
        }else if(!scrollView.tag){
            scrollView.contentOffset = CGPointMake(0, scrollView.contentSize.height - scrollView.frame.size.height);
        }
    }
}
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{
    scrollView.tag = 1;
}
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{
    scrollView.tag = 0;
}
- (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView{
    scrollView.tag = 1;
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
    scrollView.tag = 0;
}