http://sublime.nyasha.me/admin/form_masks.html
I use this technique to achieve nice results with html/css/java etc, but how does one achieve this in objective-c?
I've read so far about number formatting, but how can I literally have it so when the content is editable it displays the formatted version as they're typing and doesn't allow them to exceed .length in certain areas.
My example I need to use it for is
00:00:00 or 00h:00m:00s so when edited it will achieve __:__:__ or __h:__m:__s I've been scraping through the interwebs and cannot find such a technique, so far I've considered programatically doing something like this..
3x UITextField
1x UILabel
if (editing is commenced && value changed) {
if (.length == 2) {
Move onto next UITextField;
}
}
And display the UILabel Masked over the textfields, but also customise the textfields so 3 appears to be one.
-- EDIT
//Programming the Textfield Mask
-(void)reformatAsCardNumber:(UITextField *)textField
{
NSUInteger targetCursorPosition =
[textField offsetFromPosition:textField.beginningOfDocument
toPosition:textField.selectedTextRange.start];
NSString *cardNumberWithoutSpaces =
[self removeNonDigits:textField.text
andPreserveCursorPosition:&targetCursorPosition];
if ([cardNumberWithoutSpaces length] > 6) {
[textField setText:previousTextFieldContent];
textField.selectedTextRange = previousSelection;
return;
}
NSString *cardNumberWithSpaces =
[self insertSpacesEveryFourDigitsIntoString:cardNumberWithoutSpaces
andPreserveCursorPosition:&targetCursorPosition];
textField.text = cardNumberWithSpaces;
UITextPosition *targetPosition =
[textField positionFromPosition:[textField beginningOfDocument]
offset:targetCursorPosition];
[textField setSelectedTextRange:
[textField textRangeFromPosition:targetPosition
toPosition:targetPosition]
];
}
-(BOOL)textField:(UITextField *)textField
shouldChangeCharactersInRange:(NSRange)range
replacementString:(NSString *)string
{
previousTextFieldContent = textField.text;
previousSelection = textField.selectedTextRange;
return YES;
}
- (NSString *)removeNonDigits:(NSString *)string
andPreserveCursorPosition:(NSUInteger *)cursorPosition
{
NSUInteger originalCursorPosition = *cursorPosition;
NSMutableString *digitsOnlyString = [NSMutableString new];
for (NSUInteger i=0; i<[string length]; i++) {
unichar characterToAdd = [string characterAtIndex:i];
if (isdigit(characterToAdd)) {
NSString *stringToAdd =
[NSString stringWithCharacters:&characterToAdd
length:1];
[digitsOnlyString appendString:stringToAdd];
}
else {
if (i < originalCursorPosition) {
(*cursorPosition)--;
}
}
}
return digitsOnlyString;
}
- (NSString *)insertSpacesEveryFourDigitsIntoString:(NSString *)string
andPreserveCursorPosition:(NSUInteger *)cursorPosition
{
NSMutableString *stringWithAddedSpaces = [NSMutableString new];
NSUInteger cursorPositionInSpacelessString = *cursorPosition;
for (NSUInteger i=0; i<[string length]; i++) {
if ((i>0) && ((i % 2) == 0)) {
[stringWithAddedSpaces appendString:#":"];
if (i < cursorPositionInSpacelessString) {
(*cursorPosition)++;
}
}
unichar characterToAdd = [string characterAtIndex:i];
NSString *stringToAdd =
[NSString stringWithCharacters:&characterToAdd length:1];
[stringWithAddedSpaces appendString:stringToAdd];
}
return stringWithAddedSpaces;
}
Then to call it
[_answerTextField addTarget:self
action:#selector(reformatAsCardNumber:)
forControlEvents:UIControlEventEditingChanged];
I need the pre-determined text such as __:__:__ or preferably __h:__m:__s so when you start typing you get 00h:0_m:__ as you fill out.
As right now, I get `` then when I start typing I get 00:0 etc..
Use the textFieldShouldChange method to modify the input / move the cursor as you see fit BEFORE it is updated on the screen
it is in UITextFieldDelegate:
textField:shouldChangeCharactersInRange:replacementString:
Asks the delegate if the specified text should be changed.
The text field calls this method whenever the user types a new character in the text field or deletes an existing character.
in addition there is also textDidChange in the delegate which works AFTER the text is shown
these are DELEGATE methods so you have to become the textField's delegate:
//1 conform to the delegate
#interface MyViewController <UITextFieldDelegate>
then
//2 set yourself as delegate (can also be done through IB)
textView.delegate = self;
I have the following code where I want to convert decimal odds to fractional odds. However the function findNearestWholeInteger always returns null.
- (NSString *)displayOddWithFormat:(NSString *)decimalOdd {
if ([[NSUserDefaults standardUserDefaults] boolForKey:#"FractionalOdds"] == YES) {
float oddsF = decimalOdd.floatValue;
oddsF = oddsF - 1.0f;
return [self findNearestWholeInteger:oddsF andInitial:oddsF andBottom:1];
} else {
return odd;
}
}
- (NSString *)findNearestWholeInteger:(float)odds andInitial:(float)initial andBottom:(float)bottom {
NSNumber *numberValue = [NSNumber numberWithFloat:odds];
NSString *floatString = [numberValue stringValue];
NSArray *floatStringComps = [floatString componentsSeparatedByString:#"."];
if (floatStringComps.count == 1) {
return [NSString stringWithFormat:#"%.f/%.f", odds, bottom];
} else {
bottom += 1;
odds += initial;
[self findNearestWholeInteger:odds andInitial:initial andBottom:bottom];
return nil;
}
}
Any ideas where I need to adapt my code? Thanks in advance!
Don't you want:
return [self findNearestWholeInteger:odds andInitial:initial andBottom:bottom];
//return nil;
(not that I really understand what the method is doing).
Is there anyway i can allow user to enter only alpha numeric characters in a text view and no other character.
EDIT:
Tried,
if ([_txtView.text rangeOfCharacterFromSet:alphaSet].location != NSNotFound)
{
UIAlertView* alert = [[UIAlertView alloc] initWithTitle:#"Hello" message:#"Only alpha numeric characters are allowed" delegate:nil cancelButtonTitle:#"OK" otherButtonTitles:nil];
[alert show];
return;
}
but this only works for some of the times
Thanks!!
You can achieve that using [[[NSCharacterSet alphanumericCharacterSet] invertedSet]. This method will return a character set containing only characters that don’t exist in the receiver.
NSCharacterSet *charactersToBlock = [[NSCharacterSet alphanumericCharacterSet] invertedSet];
//Conform UITextField delegate and implement this method.
- (BOOL)textField:(UITextField *)field shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)characters
{
return ([characters rangeOfCharacterFromSet:charactersToBlock].location == NSNotFound);
}
Try this:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
if (textField == txtWebsite) {
NSCharacterSet *set = [NSCharacterSet characterSetWithCharactersInString:#"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890 "];
if ([string rangeOfCharacterFromSet:set].location != NSNotFound) {
return YES;
}
else {
return NO;
}
}
else {
return YES;
}
}
write code in delegate method of uitextfield.
set delegate for textview and override/implement test should change in range method
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
NSCharacterSet *alphaSet = [NSCharacterSet alphanumericCharacterSet];
BOOL valid = [[text stringByTrimmingCharactersInSet:alphaSet] isEqualToString:#""];
return valid;
}
Equivalent Swift 3 version of the answer provided by #user1113101
Though it's late to answer and there are other simple and great approaches, but this answer might be useful to someone.
This is simple and worked like a charm for me.
func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
/// 1. replacementText is NOT empty means we are entering text or pasting text: perform the logic
/// 2. replacementText is empty means we are deleting text: return true
if text.characters.count > 0 {
var allowedCharacters = CharacterSet.alphanumerics
let unwantedStr = text.trimmingCharacters(in: allowedCharacters)
return unwantedStr.characters.count == 0
}
return true
}
Note: This will work for pasting strings into the text field as well. Pasted string will not be displayed in text field if it contains any unwanted characters.
// Add this in ViewDidLoad or any init method
NSCharacterSet *blockedCharacters = [[[NSCharacterSet alphanumericCharacterSet] invertedSet] retain];
then Set your textfield's delegate in nib file .
- (BOOL)textField:(UITextField *)field shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)characters
{
return ([characters rangeOfCharacterFromSet:blockedCharacters].location == NSNotFound);
}
Or there is another way in shouldChangeCharactersInRange method. You can check
{
NSString *stringPlace = #"[a-z A-Z]*";
NSPredicate *testPlace = [NSPredicate predicateWithFormat:#"SELF MATCHES %#", stringPlace];
BOOL matches = [testPlace evaluateWithObject:string];
if (!matches && string.length > 5)
{
return NO;
}
return YES;
}
I want to remove the linefeed that was entered in by the return key. But when I do the following it remove the last character from the text. Why?
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text;
{
NSLog(#"%d %d %# %#",range.location,range.length, text, [textView text]);
if ( [text isEqualToString:#"\n"] ) {
NSString *s = [textView text];
s = [s substringToIndex:[s length] - 1]; // <------------
[tvText setText:[NSString stringWithFormat:#"%#\n>>",s]];
}
return YES;
}
I want the result to look like:
>>name
>>yoda
>> <---- cursor is moved to the right of ">>"
I think you can do something like this,
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text;
{
NSLog(#"%d %d %# %#",range.location,range.length, text, [textView text]);
if ( [text isEqualToString:#"\n"] ) {
[tvText setText:[NSString stringWithFormat:#"%#\n>>",tvText.text]];
return NO;
}
return YES;
}
Or maybe after your reading string in line and put it to some substring:
string = [string stringByReplacingOccurrencesOfString:#"\n;" withString:#""];
shouldChangeTextInRange is part of the UITextViewDelegate, and is called before the new text is changed in the textView. Therefore, you could just do this:
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text;
{
if ([text isEqualToString:#"\n"])
{
return NO;
}
return YES;
}
Use this for better solution as it won't allow user to post any blank message in any case.
//These for loops will remove the spaces and new line characters from start and end of the string
//&&//
NSMutableString *temp = [[NSMutableString alloc] initWithString:posttextview.text];
//Remove spaces and new line characters from start
for(int i = 0; i < yourtext.length; i++)
{
NSString *temp1 = [NSMutableString stringWithString:[temp substringWithRange:NSMakeRange(0,1)]];
if([temp1 isEqualToString:#"\n"] || [temp1 isEqualToString:#" "])
{
[temp deleteCharactersInRange:NSMakeRange(0,1)];
}
else
{
break;
}
}
yourtext.text = temp;
//Remove spaces and new line characters from end
for(int i = 0; i < yourtext.length; i++)
{
NSString *temp1 = [NSMutableString stringWithString:[temp substringWithRange:NSMakeRange(posttextview.text.length - 1,1)]];
if([temp1 isEqualToString:#"\n"] || [temp1 isEqualToString:#" "])
{
[temp deleteCharactersInRange:NSMakeRange(posttextview.text.length - 1,1)];
yourtext.text = temp;
}
else
{
break;
}
}
yourtext.text = temp;
//**//
The problem is that the time shouldChangeCharactersImRange is called, the new text is not actually changed yet (that's why it's not named didChangeCharactersInRange...). So in case you encounter a newline, don't trick with the substrings, just store/process the string the text view contains so far, and return NO.
First add the UITextViewDelegate in your .h file
#interface YourClass : UITextField <UITextFieldDelegate> {
}
then implement the delegate method
-(BOOL)shouldChangeCharactersInRange:replacementString:
How do I validate the string input to a UITextField? I want to check that the string is numeric, including decimal points.
You can do it in a few lines like this:
BOOL valid;
NSCharacterSet *alphaNums = [NSCharacterSet decimalDigitCharacterSet];
NSCharacterSet *inStringSet = [NSCharacterSet characterSetWithCharactersInString:myInputField.text];
valid = [alphaNums isSupersetOfSet:inStringSet];
if (!valid) // Not numeric
-- this is for validating input is numeric chars only. Look at the documentation for NSCharacterSet for the other options. You can use characterSetWithCharactersInString to specify any set of valid input characters.
There are a few ways you could do this:
Use NSNumberFormatter's numberFromString: method. This will return an NSNumber if it can parse the string correctly, or nil if it cannot.
Use NSScanner
Strip any non-numeric character and see if the string still matches
Use a regular expression
IMO, using something like -[NSString doubleValue] wouldn't be the best option because both #"0.0" and #"abc" will have a doubleValue of 0. The *value methods all return 0 if they're not able to convert the string properly, so it would be difficult to distinguish between a legitimate string of #"0" and a non-valid string. Something like C's strtol function would have the same issue.
I think using NSNumberFormatter would be the best option, since it takes locale into account (ie, the number #"1,23" in Europe, versus #"1.23" in the USA).
I use this code in my Mac app, the same or similar should work with the iPhone. It's based on the RegexKitLite regular expressions and turns the text red when its invalid.
static bool TextIsValidValue( NSString* newText, double &value )
{
bool result = false;
if ( [newText isMatchedByRegex:#"^(?:|0|[1-9]\\d*)(?:\\.\\d*)?$"] ) {
result = true;
value = [newText doubleValue];
}
return result;
}
- (IBAction) doTextChanged:(id)sender;
{
double value;
if ( TextIsValidValue( [i_pause stringValue], value ) ) {
[i_pause setTextColor:[NSColor blackColor]];
// do something with the value
} else {
[i_pause setTextColor:[NSColor redColor]];
}
}
If you want a user to only be allowed to enter numerals, you can make your ViewController implement part of UITextFieldDelegate and define this method:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSString *resultingString = [textField.text stringByReplacingCharactersInRange: range withString: string];
// The user deleting all input is perfectly acceptable.
if ([resultingString length] == 0) {
return true;
}
NSInteger holder;
NSScanner *scan = [NSScanner scannerWithString: resultingString];
return [scan scanInteger: &holder] && [scan isAtEnd];
}
There are probably more efficient ways, but I find this a pretty convenient way. And the method should be readily adaptable to validating doubles or whatever: just use scanDouble: or similar.
#pragma mark - UItextfield Delegate
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
if ([string isEqualToString:#"("]||[string isEqualToString:#")"]) {
return TRUE;
}
NSLog(#"Range ==%d ,%d",range.length,range.location);
//NSRange *CURRANGE = [NSString rangeOfString:string];
if (range.location == 0 && range.length == 0) {
if ([string isEqualToString:#"+"]) {
return TRUE;
}
}
return [self isNumeric:string];
}
-(BOOL)isNumeric:(NSString*)inputString{
BOOL isValid = NO;
NSCharacterSet *alphaNumbersSet = [NSCharacterSet decimalDigitCharacterSet];
NSCharacterSet *stringSet = [NSCharacterSet characterSetWithCharactersInString:inputString];
isValid = [alphaNumbersSet isSupersetOfSet:stringSet];
return isValid;
}
Here are a few one-liners which combine Peter Lewis' answer above (Check that a input to UITextField is numeric only) with NSPredicates
#define REGEX_FOR_NUMBERS #"^([+-]?)(?:|0|[1-9]\\d*)(?:\\.\\d*)?$"
#define REGEX_FOR_INTEGERS #"^([+-]?)(?:|0|[1-9]\\d*)?$"
#define IS_A_NUMBER(string) [[NSPredicate predicateWithFormat:#"SELF MATCHES %#", REGEX_FOR_NUMBERS] evaluateWithObject:string]
#define IS_AN_INTEGER(string) [[NSPredicate predicateWithFormat:#"SELF MATCHES %#", REGEX_FOR_INTEGERS] evaluateWithObject:string]
For integer test it'll be:
- (BOOL) isIntegerNumber: (NSString*)input
{
return [input integerValue] != 0 || [input isEqualToString:#"0"];
}
You can use the doubleValue of your string like
NSString *string=#"1.22";
double a=[string doubleValue];
i think this will return a as 0.0 if the string is invalid (it might throw an exception, in which case you can just catch it, the docs say 0.0 tho). more info here
Hi had the exact same problem and I don't see the answer I used posted, so here it is.
I created and connected my text field via IB. When I connected it to my code via Control+Drag, I chose Action, then selected the Editing Changed event. This triggers the method on each character entry. You can use a different event to suit.
Afterwards, I used this simple code to replace the text. Note that I created my own character set to include the decimal/period character and numbers. Basically separates the string on the invalid characters, then rejoins them with empty string.
- (IBAction)myTextFieldEditingChangedMethod:(UITextField *)sender {
NSCharacterSet *validCharacterSet = [NSCharacterSet characterSetWithCharactersInString:#".0123456789"];
NSCharacterSet *invalidCharacterSet = validCharacterSet.invertedSet;
sender.text = [[sender.text componentsSeparatedByCharactersInSet:invalidCharacterSet] componentsJoinedByString:#""];
}
Credits:
Remove all but numbers from NSString
Late to the game but here a handy little category I use that accounts for decimal places and the local symbol used for it. link to its gist here
#interface NSString (Extension)
- (BOOL) isAnEmail;
- (BOOL) isNumeric;
#end
#implementation NSString (Extension)
/**
* Determines if the current string is a valid email address.
*
* #return BOOL - True if the string is a valid email address.
*/
- (BOOL) isAnEmail
{
NSString *emailRegex = #"[A-Z0-9a-z._%+-]+#[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
NSPredicate *emailTest = [NSPredicate predicateWithFormat:#"SELF MATCHES %#", emailRegex];
return [emailTest evaluateWithObject:self];
}
/**
* Determines if the current NSString is numeric or not. It also accounts for the localised (Germany for example use "," instead of ".") decimal point and includes these as a valid number.
*
* #return BOOL - True if the string is numeric.
*/
- (BOOL) isNumeric
{
NSString *localDecimalSymbol = [[NSLocale currentLocale] objectForKey:NSLocaleDecimalSeparator];
NSMutableCharacterSet *decimalCharacterSet = [NSMutableCharacterSet characterSetWithCharactersInString:localDecimalSymbol];
[decimalCharacterSet formUnionWithCharacterSet:[NSCharacterSet alphanumericCharacterSet]];
NSCharacterSet* nonNumbers = [decimalCharacterSet invertedSet];
NSRange r = [self rangeOfCharacterFromSet: nonNumbers];
if (r.location == NSNotFound)
{
// check to see how many times the decimal symbol appears in the string. It should only appear once for the number to be numeric.
int numberOfOccurances = [[self componentsSeparatedByString:localDecimalSymbol] count]-1;
return (numberOfOccurances > 1) ? NO : YES;
}
else return NO;
}
#end
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if(string.length > 0)
{
NSCharacterSet *numbersOnly = [NSCharacterSet characterSetWithCharactersInString:#"0123456789"];
NSCharacterSet *characterSetFromTextField = [NSCharacterSet characterSetWithCharactersInString:string];
BOOL stringIsValid = [numbersOnly isSupersetOfSet:characterSetFromTextField];
return stringIsValid;
}
return YES;
}
IMO the best way to accomplish your goal is to display a numeric keyboard rather than the normal keyboard. This restricts which keys are available to the user. This alleviates the need to do validation, and more importantly it prevents the user from making a mistake. The number pad is also much nicer for entering numbers because the keys are substantially larger.
In interface builder select the UITextField, go to the Attributes Inspector and change the "Keyboard Type" to "Decimal Pad".
That'll make the keyboard look like this:
The only thing left to do is ensure the user doesn't enter in two decimal places. You can do this while they're editing. Add the following code to your view controller. This code removes a second decimal place as soon as it is entered. It appears to the user as if the 2nd decimal never appeared in the first place.
- (void)viewDidLoad
{
[super viewDidLoad];
[self.textField addTarget:self
action:#selector(textFieldDidChange:)
forControlEvents:UIControlEventEditingChanged];
}
- (void)textFieldDidChange:(UITextField *)textField
{
NSString *text = textField.text;
NSRange range = [text rangeOfString:#"."];
if (range.location != NSNotFound &&
[text hasSuffix:#"."] &&
range.location != (text.length - 1))
{
// There's more than one decimal
textField.text = [text substringToIndex:text.length - 1];
}
}
#property (strong) NSNumberFormatter *numberFormatter;
#property (strong) NSString *oldStringValue;
- (void)awakeFromNib
{
[super awakeFromNib];
self.numberFormatter = [[NSNumberFormatter alloc] init];
self.oldStringValue = self.stringValue;
[self setDelegate:self];
}
- (void)controlTextDidChange:(NSNotification *)obj
{
NSNumber *number = [self.numberFormatter numberFromString:self.stringValue];
if (number) {
self.oldStringValue = self.stringValue;
} else {
self.stringValue = self.oldStringValue;
}
}
Old thread, but it's worth mentioning that Apple introduced NSRegularExpression in iOS 4.0. (Taking the regular expression from Peter's response)
// Look for 0-n digits from start to finish
NSRegularExpression *noFunnyStuff = [NSRegularExpression regularExpressionWithPattern:#"^(?:|0|[1-9]\\d*)(?:\\.\\d*)?$" options:0 error:nil];
// There should be just one match
if ([noFunnyStuff numberOfMatchesInString:<#theString#> options:0 range:NSMakeRange(0, <#theString#>.length)] == 1)
{
// Yay, digits!
}
I suggest storing the NSRegularExpression instance somewhere.
I wanted a text field that only allowed integers. Here's what I ended up with (using info from here and elsewhere):
Create integer number formatter (in UIApplicationDelegate so it can be reused):
#property (nonatomic, retain) NSNumberFormatter *integerNumberFormatter;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
// Create and configure an NSNumberFormatter for integers
integerNumberFormatter = [[NSNumberFormatter alloc] init];
[integerNumberFormatter setMaximumFractionDigits:0];
return YES;
}
Use filter in UITextFieldDelegate:
#interface MyTableViewController : UITableViewController <UITextFieldDelegate> {
ictAppDelegate *appDelegate;
}
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
// Make sure the proposed string is a number
NSNumberFormatter *inf = [appDelegate integerNumberFormatter];
NSString* proposedString = [textField.text stringByReplacingCharactersInRange:range withString:string];
NSNumber *proposedNumber = [inf numberFromString:proposedString];
if (proposedNumber) {
// Make sure the proposed number is an integer
NSString *integerString = [inf stringFromNumber:proposedNumber];
if ([integerString isEqualToString:proposedString]) {
// proposed string is an integer
return YES;
}
}
// Warn the user we're rejecting the change
AudioServicesPlayAlertSound(kSystemSoundID_Vibrate);
return NO;
}
Not so elegant, but simple :)
- (BOOL) isNumber: (NSString*)input
{
return [input doubleValue] != 0 || [input isEqualToString:#"0"] || [input isEqualToString:#"0.0"];
}
Accept decimal values in text fields with single (.)dot working with iPad and iPhone in Swift 3
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let inverseSet = NSCharacterSet(charactersIn:"0123456789").inverted
let components = string.components(separatedBy: inverseSet)
let filtered = components.joined(separator: "")
if filtered == string {
return true
} else {
if string == "." {
let countdots = textField.text!.components(separatedBy:".").count - 1
if countdots == 0 {
return true
}else{
if countdots > 0 && string == "." {
return false
} else {
return true
}
}
}else{
return false
}
}
}
To be more international (and not only US colored ;-) ) just replace in the code above by
-(NSNumber *) getNumber
{
NSString* localeIdentifier = [[NSLocale autoupdatingCurrentLocale] localeIdentifier];
NSLocale *l_en = [[NSLocale alloc] initWithLocaleIdentifier: localeIdentifier] ;
return [self getNumberWithLocale: [l_en autorelease] ];
}
This answer uses NSFormatter as said previously. Check it out:
#interface NSString (NSNumber)
- (BOOL) isNumberWithLocale:(NSLocale *) stringLocale;
- (BOOL) isNumber;
- (NSNumber *) getNumber;
- (NSNumber *) getNumberWithLocale:(NSLocale*) stringLocale;
#end
#implementation NSString (NSNumber)
- (BOOL) isNumberWithLocale:(NSLocale *) stringLocale
{
return [self getNumberWithLocale:stringLocale] != nil;
}
- (BOOL) isNumber
{
return [ self getNumber ] != nil;
}
- (NSNumber *) getNumber
{
NSLocale *l_en = [[NSLocale alloc] initWithLocaleIdentifier: #"en_US"] ;
return [self getNumberWithLocale: [l_en autorelease] ];
}
- (NSNumber *) getNumberWithLocale:(NSLocale*) stringLocale
{
NSNumberFormatter *formatter = [[ [ NSNumberFormatter alloc ] init ] autorelease];
[formatter setLocale: stringLocale ];
return [ formatter numberFromString:self ];
}
#end
I hope it helps someone. =)
#import "NSString+Extension.h"
//#interface NSString (Extension)
//
//- (BOOL) isAnEmail;
//- (BOOL) isNumeric;
//
//#end
#implementation NSString (Extension)
- (BOOL) isNumeric
{
NSString *emailRegex = #"[0-9]+";
NSPredicate *emailTest = [NSPredicate predicateWithFormat:#"SELF MATCHES %#", emailRegex];
return [emailTest evaluateWithObject:self];
// NSString *localDecimalSymbol = [[NSLocale currentLocale] objectForKey:NSLocaleDecimalSeparator];
// NSMutableCharacterSet *decimalCharacterSet = [NSMutableCharacterSet characterSetWithCharactersInString:localDecimalSymbol];
// [decimalCharacterSet formUnionWithCharacterSet:[NSCharacterSet alphanumericCharacterSet]];
//
// NSCharacterSet* nonNumbers = [decimalCharacterSet invertedSet];
// NSRange r = [self rangeOfCharacterFromSet: nonNumbers];
//
// if (r.location == NSNotFound)
// {
// // check to see how many times the decimal symbol appears in the string. It should only appear once for the number to be numeric.
// int numberOfOccurances = [[self componentsSeparatedByString:localDecimalSymbol] count]-1;
// return (numberOfOccurances > 1) ? NO : YES;
// }
// else return NO;
}
In Swift 4:
let formatString = "12345"
if let number = Decimal(string:formatString){
print("String contains only number")
}
else{
print("String doesn't contains only number")
}
This covers: Decimal part control (including number of decimals allowed), copy/paste control, international separators.
Steps:
Make sure your view controller inherits from UITextFieldDelegate
class MyViewController: UIViewController, UITextFieldDelegate {...
In viewDidLoad, set your control delegate to self:
override func viewDidLoad() {
super.viewDidLoad();
yourTextField.delegate = self
}
Implement the following method and update the "decsAllowed" constant with the desired amount of decimals or 0 if you want a natural number.
Swift 4
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let decsAllowed: Int = 2
let candidateText = NSString(string: textField.text!).replacingCharacters(in: range, with: string)
let decSeparator: String = NumberFormatter().decimalSeparator!;
let splitted = candidateText.components(separatedBy: decSeparator)
let decSeparatorsFound = splitted.count - 1
let decimalPart = decSeparatorsFound > 0 ? splitted.last! : ""
let decimalPartCount = decimalPart.characters.count
let characterSet = NSMutableCharacterSet.decimalDigit()
if decsAllowed > 0 {characterSet.addCharacters(in: decSeparator)}
let valid = characterSet.isSuperset(of: CharacterSet(charactersIn: candidateText)) &&
decSeparatorsFound <= 1 &&
decsAllowed >= decimalPartCount
return valid
}
If afterwards you need to safely convert that string into a number, you can just use Double(yourstring) or Int(yourstring) type cast, or the more academic way:
let formatter = NumberFormatter()
let theNumber: NSNumber = formatter.number(from: yourTextField.text)!