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I'm trying to format two NSTextFields for SMPTE time codes, which have the format:
HH:MM:SS:FF. However, when the user switches the SMPTE code to drop-frame, the delimiter between SS and FF needs to switch to a ; (HH:MM:SS;FF). To do this, I've subclassed NSFormatter, and have it mostly working except for one very stubborn problem.
The text field accepts input just fine, but if I highlight-replace, backspace, delete, or insert any new characters into the text field, I get an NSBeep and I can't switch focus away from the text field. I can input new text if I delete the whole text field first, but not if I try to edit the existing input. Here are my implemented methods/overrides:
- (NSString*)stringForObjectValue:(id)obj
{
if ( ! [obj isKindOfClass:[NSNumber class]])
{
return nil;
}
NSMutableString *string = [NSMutableString stringWithString:#"00:00:00:00"];
int length = (int)[[obj stringValue] length];
int insertLocation = 9;
if (length == 1)
{
[string replaceCharactersInRange:NSMakeRange(10, 1) withString:[obj stringValue]];
}
else
{
while (length > 1)
{
NSString *temp = [[obj stringValue] substringFromIndex:length-2];
[string replaceCharactersInRange:NSMakeRange(insertLocation, 2) withString:temp];
obj = [NSNumber numberWithInt:[obj intValue]/100];
length -= 2;
insertLocation -= 3;
}
if (length == 1)
{
[string replaceCharactersInRange:NSMakeRange(insertLocation+1, 1) withString:[obj stringValue]];
}
}
return string;
}
- (BOOL)getObjectValue:(out __autoreleasing id *)obj forString:(NSString *)string errorDescription:(out NSString *__autoreleasing *)error
{
int valueResult;
NSScanner *scanner;
BOOL returnValue = NO;
scanner = [NSScanner scannerWithString: string];
[scanner scanString:#":" intoString:NULL];
[scanner scanString:#";" intoString:NULL];
if ([scanner scanInt:&valueResult] && ([scanner isAtEnd])) {
returnValue = YES;
if (obj)
{
*obj = [NSNumber numberWithInt:valueResult];
}
}
return returnValue;
}
At least at this point, I don't need to validate the input during editing, only when editing is finished. I tried implementing isPartialStringValid and just returning YES, but that didn't seem to help either. Any help would be greatly appreciated!
Ok, I just solved it by doing some more testing. It appears as though why it was failing is because getObjectValue was receiving the string with the delimiters in them and was not correctly removing them. I simply replaced the method with this:
- (BOOL)getObjectValue:(out __autoreleasing id *)obj forString:(NSString *)string errorDescription:(out NSString *__autoreleasing *)error
{
NSString *newString = [string stringByReplacingOccurrencesOfString:#":" withString:#""];
if (obj)
{
*obj = [NSNumber numberWithInt:[newString intValue]];
return YES;
}
return NO;
}
Now it works perfectly.
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've bound the NSComboBox bounded to a data source within interface builder.
I correctly get the autocomplete suggestions, when I type something in the NSComboBox.
However the autocomplete is case sensitive, which means I don't get suggestion if the character uses the wrong case.
How can I enable case insensitive autocomplete for a NSComboBox, which is bound to the data source in interface builder ?
Thanks
You should implement comboBox:completedString: in your NSComboBox Data Source, e.g:
- (NSString *)comboBox:(NSComboBox *)comboBox completedString:(NSString *)partialString
{
for (NSString dataString in dataSourceArray) {
if ([[dataString commonPrefixWithString:partialString options:NSCaseInsensitiveSearch] length] == [commonPrefixWithString:partialString length]) {
return testItem;
}
}
return #"";
}
you can subclassing an NSComboBoxCell and overriding [NSComboBoxCell completedString:].
- (NSString *)completedString:(NSString *)string
{
NSString *result = nil;
if (string == nil)
return result;
for (NSString *item in self.objectValues) {
NSString *truncatedString = [item substringToIndex:MIN(item.length, string.length)];
if ([truncatedString caseInsensitiveCompare:string] == NSOrderedSame) {
result = item;
break;
}
}
return result;
}
I am trying to get the IP Address using NSHost. With the NSHost object I can use the addresses method to access an array of objects one of which is the IP Address. I fear though that the IP Address may change position in the array from one machine to the other. Is there a way to access this information in a universal way?
There was an attempt to answer this question in a previous post, but as you can see it falls short.
IP Address? - Cocoa
Here is my code:
+(NSString *) ipAddress {
NSHost * h = [[[NSHost currentHost] addresses] objectAtIndex:1];
return h ;
}
The only thing I can think of is to use something like "http://www.dyndns.org/cgi-bin/check_ip.cgi" others may have a better way.
This is an example,(i.e a quick cobbled together code)
NSUInteger an_Integer;
NSArray * ipItemsArray;
NSString *externalIP;
NSURL *iPURL = [NSURL URLWithString:#"http://www.dyndns.org/cgi-bin/check_ip.cgi"];
if (iPURL) {
NSError *error = nil;
NSString *theIpHtml = [NSString stringWithContentsOfURL:iPURL
encoding:NSUTF8StringEncoding
error:&error];
if (!error) {
NSScanner *theScanner;
NSString *text = nil;
theScanner = [NSScanner scannerWithString:theIpHtml];
while ([theScanner isAtEnd] == NO) {
// find start of tag
[theScanner scanUpToString:#"<" intoString:NULL] ;
// find end of tag
[theScanner scanUpToString:#">" intoString:&text] ;
// replace the found tag with a space
//(you can filter multi-spaces out later if you wish)
theIpHtml = [theIpHtml stringByReplacingOccurrencesOfString:
[ NSString stringWithFormat:#"%#>", text]
withString:#" "] ;
ipItemsArray =[theIpHtml componentsSeparatedByString:#" "];
an_Integer=[ipItemsArray indexOfObject:#"Address:"];
externalIP =[ipItemsArray objectAtIndex: ++an_Integer];
}
NSLog(#"%#",externalIP);
} else {
NSLog(#"Oops... g %d, %#",
[error code],
[error localizedDescription]);
}
}
[pool drain];
return 0;}
I have used this on many machines without problems.
-(void) getIPWithNSHost{
NSArray *addresses = [[NSHost currentHost] addresses];
for (NSString *anAddress in addresses) {
if (![anAddress hasPrefix:#"127"] && [[anAddress componentsSeparatedByString:#"."] count] == 4) {
stringAddress = anAddress;
break;
} else {
stringAddress = #"IPv4 address not available" ;
}
}
//NSLog (#"getIPWithNSHost: stringAddress = %# ",stringAddress);
}
NSString *stringAddress; is declared else where
I wanted to update my original answer on getting an external ip.
There is not much change but I wanted to show how to get and parse the HTML with use NSXMLDocument and Xquary
This also gives a small illustration of how you can parse HTML by getting the nodes. Which in my opinion is more straight forward. Although NSXMLDocument is initially for XML it will parse the HTML DOM tree
NSString *externalIP;
///--DYNDNS.ORG URL
NSURL *iPURL = [NSURL URLWithString:#"http://www.dyndns.org/cgi-bin/check_ip.cgi"];
if (iPURL) {
NSError *err_p = nil;
//--use NSXMLDocument to get the url:(*Requests NSXMLNode to preserve whitespace characters (such as tabs and carriage returns) in the XML source that are not part of node content*)
NSXMLDocument * xmlDoc = [[NSXMLDocument alloc] initWithContentsOfURL:iPURL
options:(NSXMLNodePreserveWhitespace|
NSXMLNodePreserveCDATA)
error:&err_p];
if (xmlDoc == nil) {
//-- That did not work so lets see if we can change the malformed XML into valid XML during processing of the document.
xmlDoc = [[NSXMLDocument alloc] initWithContentsOfURL:iPURL
options:NSXMLDocumentTidyXML
error:&err_p];
}
if (!err_p) {
NSError * error;
//-- We will use XQuary to get the text from the child node. Dyndns.org page is very simple. So we just need to get the Body text.
NSString *xpathQueryTR = #"//body/text()";
//-- we get the first node's string value. We use string value to in effect cast to NSString.
//We the seperate the string into components using a space. and obtain the last object in the returned array.
//--This gives us the IP string without the "Current IP Address:" string.
externalIP = [[[[[xmlDoc nodesForXPath:xpathQueryTR error:&error]objectAtIndex:0] stringValue]componentsSeparatedByString:#" "]lastObject];
if (!error) {
NSLog(#"%#",externalIP);
}else {
NSLog(#"Oops... g %ld, %#",
(long)[error code],
[error localizedDescription]);
}
}else {
NSLog(#"Oops... g %ld, %#",
(long)[err_p code],
[err_p localizedDescription]);
}
}
Made an utility class to find the IP addresses. Minimalistic approach. You can robustify it with more conditions or regex checking.
NSLog(#"Addresses: %#", [[NSHost currentHost] addresses]);
This is the list returned by NSHost
"fe80::1610:9fff:fee1:8c2f%en0",
"192.168.212.61",
"fe80::2829:3bff:fee6:9133%awdl0",
"fe80::e54b:8494:bbc8:3989%utun0",
"fd68:cc16:fad8:ded9:e54b:8494:bbc8:3989",
"10.11.51.61",
"::1",
"127.0.0.1",
"fe80::1%lo0"
Test method,
- (void)testHost {
NSLog(#"Addresses: %#", [[NSHost currentHost] addresses]);
for (NSString *s in [[NSHost currentHost] addresses]) {
IPAddress *addr = [[IPAddress alloc] initWithString:s];
if (![addr isLocalHost] && [addr isIPV4]) {
// do something
}
}
}
IPAddress.h
#import <Foundation/Foundation.h>
#interface IPAddress : NSObject
#property (nonatomic, strong) NSString *IPAddress;
- (id)initWithString:(NSString *)ipaddress;
- (BOOL)isLocalHost;
- (BOOL) isIPV4;
- (BOOL) isIPV6;
#end
IPAddress.m
#import "IPAddress.h"
#implementation IPAddress
- (id)initWithString:(NSString *)ipaddress {
self = [super init];
if (self) {
self.IPAddress = ipaddress;
}
return self;
}
- (BOOL)isLocalHost {
if (self.IPAddress == nil) return NO;
if ([#"127.0.0.1" compare:self.IPAddress options:NSCaseInsensitiveSearch] == NSOrderedSame) {
return YES;
}
if ([#"localhost" compare:self.IPAddress options:NSCaseInsensitiveSearch] == NSOrderedSame) {
return YES;
}
if ([#"::1" compare:self.IPAddress options:NSCaseInsensitiveSearch] == NSOrderedSame) {
return YES;
}
return NO;
}
- (BOOL) isIPV4 {
NSArray *ar = [self.IPAddress componentsSeparatedByString:#"."];
if (ar.count == 4) {
return YES;
}
return NO;
}
- (BOOL) isIPV6 {
if (![self isIPV4]) {
if ([self.IPAddress rangeOfString:#":"].location != NSNotFound) {
return YES;
}
}
return NO;
}
#end
As the answers to the question you mention above have said, there are a variety of IP addresses that a single machine can have. If that is what you want, then you might be better off using the names method of NSHost to get an array of names, which you can then filter for the suffix (i.e *.lan) to get the name of the host you want with this name. In my case. the .lan address returns my network ip address as a dotted quad.
If you want to find the external ip address, then this is a good answer to look at.
My first Answer is to supply the Private IP address assigned to the Machine on private network from say your router.
If you want to see the public IP, which is the one facing the internet. Normally assigned by your service provider. You may want to look at the answer by Jim Dovey --> here
I tested it and it worked well, but read the rest of the comments and answers which point to ambiguities in trying to get a public IP.
You can create a category on NSHost and do something like this:
#import <arpa/inet.h>
#import <ifaddrs.h>
#import <net/if.h>
.h
+ (NSDictionary *) interfaceIP4Addresses;
+ (NSDictionary *) interfaceIP6Addresses;
+ (NSDictionary *) interfaceIPAddresses;
.m
typedef NS_ENUM(NSUInteger, AddressType) {
AddressTypeBoth = 0,
AddressTypeIPv4 = 1,
AddressTypeIPv6 = 2
};
#implementation SomeClass
#pragma mark - Helper Methods:
+ (NSDictionary *) _interfaceAddressesForFamily:(AddressType)family {
NSMutableDictionary *interfaceInfo = [NSMutableDictionary dictionary];
struct ifaddrs *interfaces;
if ( (0 == getifaddrs(&interfaces)) ) {
struct ifaddrs *interface;
for ( interface=interfaces; interface != NULL; interface=interface->ifa_next ) {
if ( (interface->ifa_flags & IFF_UP) && !(interface->ifa_flags & IFF_LOOPBACK) ) {
const struct sockaddr_in *addr = (const struct sockaddr_in *)interface->ifa_addr;
if ( addr && addr->sin_family == PF_INET ) {
if ( (family == AddressTypeBoth) || (family == AddressTypeIPv4) ) {
char ip4Address[INET_ADDRSTRLEN];
inet_ntop( addr->sin_family, &(addr->sin_addr), ip4Address, INET_ADDRSTRLEN );
[interfaceInfo setObject:[NSString stringWithUTF8String:interface->ifa_name]
forKey:[NSString stringWithUTF8String:ip4Address]];
} } else if ( addr && addr->sin_family == PF_INET6 ) {
if ( (family == AddressTypeBoth) || (family == AddressTypeIPv6) ) {
char ip6Address[INET6_ADDRSTRLEN];
inet_ntop( addr->sin_family, &(addr->sin_addr), ip6Address, INET6_ADDRSTRLEN );
[interfaceInfo setObject:[NSString stringWithUTF8String:interface->ifa_name]
forKey:[NSString stringWithUTF8String:ip6Address]];
} }
}
} freeifaddrs( interfaces );
} return [NSDictionary dictionaryWithDictionary:interfaceInfo];
}
#pragma mark - Class Methods:
+ (NSDictionary *) interfaceIP4Addresses { return [self _interfaceAddressesForFamily:AddressTypeIPv4]; }
+ (NSDictionary *) interfaceIP6Addresses { return [self _interfaceAddressesForFamily:AddressTypeIPv6]; }
+ (NSDictionary *) interfaceIPAddresses { return [self _interfaceAddressesForFamily:AddressTypeBoth]; }
#end
This works really fast and well. If you need other info or to monitor then use System Configuration framework.
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)!