下面这个限制输入金额限制得很死:

•  1.要求用户输入首位不能为小数点;
• 2.小数点后不超过两位，小数点无法输入超过一个;
• 3.如果首位为0，后面仅能输入小数点；
• 4.输入金额不超过11位。

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1 -(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string 2 { 3     if (textField.text.length > 10) { 4         return range.location < 11; 5     }else{ 6         BOOL isHaveDian = YES; 7         if ([textField.text rangeOfString:@"."].location==NSNotFound) { 8             isHaveDian=NO; 9         }10         if ([string length]>0)11         {12             unichar single=[string characterAtIndex:0];//当前输入的字符13             14             if ((single >='0' && single<='9') || single=='.')//数据格式正确15             {16                 //首字母不能为小数点17                 if([textField.text length]==0){18                     if(single == '.'){19                         [textField.text stringByReplacingCharactersInRange:range withString:@""];20                         return NO;21                         22                     }23                 }24                 if([textField.text length]==1 && [textField.text isEqualToString:@"0"]){25                     if(single != '.'){26                         [textField.text stringByReplacingCharactersInRange:range withString:@""];27                         return NO;28                         29                     }30                 }31                 if (single=='.')32                 {33                     if(!isHaveDian)//text中还没有小数点34                     {35                         isHaveDian=YES;36                         return YES;37                     }else38                     {39                         [textField.text stringByReplacingCharactersInRange:range withString:@""];40                         return NO;41                     }42                 }43                 else44                 {45                     if (isHaveDian)//存在小数点46                     {47                         //判断小数点的位数48                         NSRange ran=[textField.text rangeOfString:@"."];49                         NSInteger tt=range.location-ran.location;50                         if (tt <= 2){51                             return YES;52                         }else{53                             return NO;54                         }55                     }56                     else57                     {58                         return YES;59                     }60                 }61             }else{
   //输入的数据格式不正确62                 [textField.text stringByReplacingCharactersInRange:range withString:@""];63                 return NO;64             }65         }66         else67         {68             return YES;69         }70     }71 }