Amount Value Truncation in ios - iphone

Question

In my app, i have an amount field. It should accept only 6 digits BEFORE decimal point and any number of digits AFTER decimal point which will be rounded off to 2 digits. How to do this.? For Example, typing in 12345678 can be truncated to 123456 on clicking RETURN key.. Same way, 12345678.75 -> 123456 123456.456 -> 123456.46

Answer 1

This code should help.
double input = 12345678.75;
double output;
NSString *string = [NSString stringWithFormat:#"%lf", input];
int dotPosition = [string rangeOfString:#"."].location;
if(dotPosition == NSNotFound || dotPosition > 6)
{
output = [string substringToIndex:6].doubleValue;
}
else
{
output = round(input * 100) / 100;
}
UPD according to iPhoneDev's comment:
Previous part of code takes and returns double values.
Here is code whitch deals wiht strings:
NSString * input = #"123456.754";
NSString * output;
int dotPosition = [input rangeOfString:#"."].location;
if(dotPosition == NSNotFound || dotPosition > 6)
{
output = [input substringToIndex:6];
}
else
{
NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
formatter.decimalSeparator = #".";
[formatter setRoundingMode: NSNumberFormatterRoundHalfUp];
[formatter setMaximumFractionDigits:2];
output = [formatter stringFromNumber:#(input.doubleValue)];
}

Answer 2

Use this code
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
NSString* proposedString = [textField.text stringByReplacingCharactersInRange:range withString:string];
//if there is empty string return YES
if([proposedString length] == 0) {
return YES;
}
//create inverted set for appripriate symbols
NSCharacterSet *nonNumberSet = [[NSCharacterSet characterSetWithCharactersInString:#"0123456789.,"] invertedSet];
//if side symbols is trimmed by nonNumberSet - return NO
if([proposedString stringByTrimmingCharactersInSet:nonNumberSet].length != [proposedString length]) {
return NO;
}
if([[proposedString componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:#"."]] count] > 2) {
return NO;
}
//finally check is ok, return YES
return YES;
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField{
NSArray *components = [textField.text componentsSeparatedByString:#"."];
// Below 6 & 2 are the range
NSString *leftString;
if ([[components objectAtIndex:0] length] > 6) {
leftString = [[components objectAtIndex:0] substringToIndex:6];
}
NSString *rightString;
if ([[components objectAtIndex:1] length] > 2) {
rightString = [[components objectAtIndex:1] substringToIndex:2];
}
[textField setText:[NSString stringWithFormat:#"%#.%#",leftString,rightString]];
[textField resignFirstResponder];
return YES;
}

Answer 3

double input = 123456.4645;
double output;
NSString *string = [NSString stringWithFormat:#"%lf", input];
int dotPosition = [string rangeOfString:#"."].location;
if(dotPosition == NSNotFound || dotPosition > 6)
{
output = [string substringToIndex:6].doubleValue;
}
else
{
double Rate_int = [input doubleValue];
NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
[formatter setRoundingMode: NSNumberFormatterRoundHalfUp];
[formatter setMaximumFractionDigits:2];
NSString *numberString = [formatter stringFromNumber:[NSNumber numberWithDouble:Rate_int]];
output = [numberString doubleValue];
}