IOS 中UITextField,UITextView,UILabel 根据内容来计算高度

ios 中uitextfield,uitextview,uilabel 根据内容来计算高度

在开发的过程中，常常遇到根据内容来决定控件的高度的情况，常见的就是uitextfield,uitextview,uilabel这三个控件，下面一uitextview 为例来说明一下：

首先新新建一个textview. 设施text，font

 uitextview *textview = [[uitextview alloc] init];
  textview.text = @"2015-01-19 14:07:47.290 microport[3047:103721] -[pprevealsideviewcontroller gesturerecognizerdidtap:] [line 1463] yes, the tap gesture is animated, this is normal, not a bug! is there anybody here with a non animate interface? :p";
  textview.font = [uifont systemfontofsize:14];
 float width =200;
 float height =[self heightforstring:textview.text fontsize:14 andwidth:width];
 textview.frame = cgrectmake(0,0,width,height);
  [self.view addsubview:textview];

计算textview高度的方法

- (float)heightforstring:(nsstring *)value fontsize:(float)fontsize andwidth:(float)width//根据字符串的的长度来计算uitextview的高度
{
  float height = [[nsstringstringwithformat:@"%@\n ",value] boundingrectwithsize:cgsizemake(width, cgfloat_max) options:nsstringdrawinguseslinefragmentorigin | nsstringdrawingusesfontleadingattributes:[nsdictionarydictionarywithobjectsandkeys:[uifontsystemfontofsize:fontsize],nsfontattributename, nil] context:nil].size.height;
  
  return height;
  
}

一般情况下常见的需求这个方法都能够满足