iOS开发-UITextView根据内容自适应高度

UITextView作为内容文本输入区域，有的时候我们需要根据内容动态改变文本区域的高度，效果如下:

定义UITextView，实现UITextViewDelegate:

-(UITextView *)textView{
    if (!_textView) {
        //http://www.cnblogs.com/xiaofeixiang/
        _textView=[[UITextView alloc]initWithFrame:CGRectMake(30, 200, CGRectGetWidth([[UIScreen mainScreen] bounds])-60, 30)];
        [_textView setTextColor:[UIColor redColor]];
        [_textView.layer setBorderColor:[[UIColor blackColor] CGColor]];
        [_textView setFont:[UIFont systemFontOfSize:15]];
        [_textView.layer setBorderWidth:1.0f];
        [_textView setDelegate:self];
    }
    return _textView;
}

实现textViewDidChange方法:

-(void)textViewDidChange:(UITextView *)textView{
    //博客园-FlyElephant
    static CGFloat maxHeight =60.0f;
    CGRect frame = textView.frame;
    CGSize constraintSize = CGSizeMake(frame.size.width, MAXFLOAT);
    CGSize size = [textView sizeThatFits:constraintSize];
    if (size.height<=frame.size.height) {
        size.height=frame.size.height;
    }else{
        if (size.height >= maxHeight)
        {
            size.height = maxHeight;
            textView.scrollEnabled = YES;   // 允许滚动
        }
        else
        {
            textView.scrollEnabled = NO;    // 不允许滚动
        }
    }
    textView.frame = CGRectMake(frame.origin.x, frame.origin.y, frame.size.width, size.height);
}