使用UITextField限制输入金额是正确小数

if(single == '.'){
　　[textField.text stringByReplacingCharactersInRange:range withString:@""];
　　return NO; 
}

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if (textField.text.length > ) {
return range.location < ;
}else{
BOOL isHaveDian = YES;
if ([textField.text rangeOfString:@"."].location==NSNotFound) {
isHaveDian=NO;
}
if ([string length]>)
{
unichar single=[string characterAtIndex:];//当前输入的字符
if ((single >='' && single<='') || single=='.')//数据格式正确
{
//首字母不能为小数点
if([textField.text length]==){
if(single == '.'){
[textField.text stringByReplacingCharactersInRange:range withString:@""];
return NO;
}
}
if([textField.text length]== && [textField.text isEqualToString:@""]){
if(single != '.'){
[textField.text stringByReplacingCharactersInRange:range withString:@""];
return NO;
}
}
if (single=='.')
{
if(!isHaveDian)//text中还没有小数点
{
isHaveDian=YES;
return YES;
}else
{
[textField.text stringByReplacingCharactersInRange:range withString:@""];
return NO;
}
}
else
{
if (isHaveDian)//存在小数点
{
//判断小数点的位数
NSRange ran=[textField.text rangeOfString:@"."];
NSInteger tt=range.location-ran.location;
if (tt <= ){
return YES;
}else{
return NO;
}
}
else
{
return YES;
}
}
}else{//输入的数据格式不正确
[textField.text stringByReplacingCharactersInRange:range withString:@""];
return NO;
}
}
else
{
return YES;
}
}
}