can anyone tell how to access only alphabets through keyboard. Numbers and special characters should not de entered into the UILabel.
I'am new to iOS programming and I'am searching this from last 2 hours of no use. Help me out of this
try this ...
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range
{
static NSCharacterSet *charSet2 = nil;
if(textField==txtfirstname)
{
if(!charSet2)
{
charSet2 = [[NSCharacterSet characterSetWithCharactersInString:#"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ "] invertedSet];
}
NSRange location = [string rangeOfCharacterFromSet:charSet2];
return (location.location == NSNotFound);
}
}
Hope this helps...
To get a notification you'll have to use the delegate function of UITextField. If you use the UILabel. You might have to go ahead and use the Keyboard notifications. Instead what you can do is use the UITextField. You can use the UITextField border style property to make it look a like UILabel.
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
NSCharacterSet *myCharSet = [NSCharacterSet characterSetWithCharactersInString:#"0123456789"];
for (int i = 0; i < [string length]; i++)
{
unichar c = [string characterAtIndex:i];
if (![myCharSet characterIsMember:c])
{
return YES;
}
else
{
return NO;
}
}
}
Related
I am having 4 text fields in which I want to put two limitations simultaneously. One is that the user should be able to type in only capital letters with the maximum character limit to 2 only. My code for this is as follows:-
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range
replacementString:(NSString *)string {
// Below logic is for All 4 Modifer Textfields
// we are restrict the user to enter only max 2 characters in modifier textfields.
if (textField==txt_modifier1 || textField==txt_modifier2 || textField==txt_modifier3 ||
textField==txt_modifier4) {
textField.text = [textField.text stringByReplacingCharactersInRange:range
withString:[string
uppercaseStringWithLocale:[NSLocale currentLocale]]];
NSUInteger newLength = [textField.text length] + [string length] - range.length;
return (newLength > 2) ? NO : YES;
}
return YES;
}
this is not functioning properly as it is appending one more character as I type in any character and also not limiting the number of characters to 2. Please suggest a way to tackle this problem.
You're manually updating the text in your textfield and then sending YES back (which then appends the characters a second time). Then, you're usingthe new text with the replacement string to compare it to two (which, then appends your characters again) ...
Try this:
if (...) {
NSString *result = [textField.text stringByReplacingCharactersInRange:range
withString:string.uppercaseString];
if (result.length <= 2)
textField.text = result;
return NO;
}
return YES;
For limiting the number of characters and capitalizing it in your UITextField, use this code block
-(BOOL) textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
textField.text = [textField.text capitalizedString];
if(textField.text.length >= 3 && range.length == 0)
{
return NO;
}
else
{
return YES;
}
Please try to use this one ...It may help you
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if([string isEqualToString:[string capitalizedString]])
{
NSString *result = [textField.text stringByReplacingCharactersInRange:range
withString:string.uppercaseString];
if (result.length <= 2)
textField.text = result;
return NO;
}
else
return YES;
}
loginUITextFieldTextDidChangeNotificationMake judgment here
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(textChanged:)
name:UITextFieldTextDidChangeNotification
object:YOUR_TEXT_FIELD];
-(void)textChanged:(NSNotification *)notif {
//to do your logic
}
I'm doing the calculator tutorial for iOS and I've done some research for doing the decimal style. So far on my research, I've gone through this code below
- (IBAction)digitPressed:(UIButton *)sender {
NSString *digit = sender.currentTitle;
NSString *decimal = #".";
BOOL decimalAlreadyEntered = [self.display.text rangeOfString:decimal].location == NSNotFound ? NO : YES;
if (self.userIsInTheMiddleOfEnteringANumber) {
if (([digit isEqual:decimal] && !decimalAlreadyEntered) || !([digit isEqual:decimal])) {
[self.display setText:[[self.display text] stringByAppendingString:digit]];
}
}
else if ([self.display.text isEqual:#"0"] && digit == decimal){
[self.display setText:[[self.display text] stringByAppendingString:digit]];
self.userIsInTheMiddleOfEnteringANumber = YES;
}
else {
[self.display setText:digit];
self.userIsInTheMiddleOfEnteringANumber = YES;
}
}
This code helped me to prevent multiple decimal points being pressed by the user, and limit it only to one (as in 2.09). Cool! However during the start of the app, when I press on the decimal point and pressed on a number, say 1, the label will only display ( .1) instead of (0.1) . Any help for the improvement is much appreciated :)
In - (BOOL) textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string you can check whether first value is "." then replace text value by "0.", whatever user has entered.And perform this check only when textfield value is ".something".
- (BOOL) textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
NSString *symbol = [[NSLocale currentLocale] objectForKey:NSLocaleDecimalSeparator];
if (range.location == 0 && [string isEqualToString:symbol]) {
// decimalseparator is first
textField.text = [NSString stringWithFormat:#"0%#",textField.text];
return YES;
}
}
I have a UITextField where user can enter a name and save it. But, user should not be allowed to enter blank spaces in the textFiled.
1 - How can I find out,if user has entered two blank spaces or complete blank spaces in the textFiled
2 - How can i know if the textFiled is filled only with blank spaces
edit - It is invalid to enter only white spaces(blank spaces)
You can "trim" the text, that is remove all the whitespace at the start and end. If all that's left is an empty string, then only whitespace (or nothing) was entered.
NSString *rawString = [textField text];
NSCharacterSet *whitespace = [NSCharacterSet whitespaceAndNewlineCharacterSet];
NSString *trimmed = [rawString stringByTrimmingCharactersInSet:whitespace];
if ([trimmed length] == 0) {
// Text was empty or only whitespace.
}
If you want to check whether there is any whitespace (anywhere in the text), you can do it like this:
NSRange range = [rawString rangeOfCharacterFromSet:whitespace];
if (range.location != NSNotFound) {
// There is whitespace.
}
If you want to prevent the user from entering whitespace at all, see #Hanon's solution.
if you really want to 'restrict' user from entering white space
you can implement the following method in UITextFieldDelegate
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSString *resultingString = [textField.text stringByReplacingCharactersInRange: range withString: string];
NSCharacterSet *whitespaceSet = [NSCharacterSet whitespaceCharacterSet];
if ([resultingString rangeOfCharacterFromSet:whitespaceSet].location == NSNotFound) {
return YES;
} else {
return NO;
}
}
If user enter space in the field, there is no change in the current text
Use following lines of code
NSString *str_test = #"Example ";
NSCharacterSet *whitespaceSet = [NSCharacterSet whitespaceCharacterSet];
if([str_test rangeOfCharacterFromSet:whitespaceSet].location!=NSNotFound)
{
NSLog(#"Found");
}
if you want to restrict user use below code
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if([string isEqualToString:#" "])
{
return NO
}
else
{
return YES
}
}
UPD: Swift 2.0 Support
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
let whitespaceSet = NSCharacterSet.whitespaceCharacterSet()
let range = string.rangeOfCharacterFromSet(whitespaceSet)
if let _ = range {
return false
}
else {
return true
}
}
I had a same condition not allowing user to input blank field
Here is my code and check statement
- (IBAction)acceptButtonClicked:(UIButton *)sender {
if ([self textFieldBlankorNot:fullNametext]) {
fullNametext.text=#"na";
}
// saving value to dictionary and sending to server
}
-(BOOL)textFieldBlankorNot:(UITextField *)textfield{
NSString *rawString = [textfield text];
NSCharacterSet *whitespace = [NSCharacterSet whitespaceAndNewlineCharacterSet];
NSString *trimmed = [rawString stringByTrimmingCharactersInSet:whitespace];
if ([trimmed length] == 0)
return YES;
else
return NO;
}
Heres Swift 3 version
let whitespaceSet = NSCharacterSet.whitespaces
let range = string.rangeOfCharacter(from: whitespaceSet)
if let _ = range {
return false
}
else {
return true
}
In Swift,
if you want to restrict the user, you can use contains()
For Example,
if userTextField.text!.contains(" "){
//your code here.....
}
Here's what I did using stringByReplacingOccurrencesOfString.
- (BOOL)validateFields
{
NSString *temp = [textField.text stringByReplacingOccurrencesOfString:#" "
withString:#""
options:NSLiteralSearch
range:NSMakeRange(0, textField.text.length)];
if ([temp length] == 0) {
// Alert view with message #"Please enter something."
return NO;
}
}
#Hanon's answer is the pretty neat, but what I needed was to allow at least 1 white space, so based on Hanon's solution I made this one:
I declared a local variable called whitespaceCount to keep the counts of the white spaces.
Hope this helps anybody!
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
NSCharacterSet *whitespaceSet = [NSCharacterSet whitespaceCharacterSet];
if ([string rangeOfCharacterFromSet:whitespaceSet].location != NSNotFound)
{
whitespaceCount++;
if (whitespaceCount > 1)
{
return NO;
}
}
else
{
whitespaceCount = 0;
return YES;
}
}
This question already has answers here:
Set the maximum character length of a UITextField
(46 answers)
Closed 10 years ago.
Is there any way to set the maximum length on a UITextField?
Something like the MAXLENGTH attribute in HTML input fields.
This works correctly with backspace and copy & paste:
#define MAXLENGTH 10
- (BOOL)textField:(UITextField *) textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSUInteger oldLength = [textField.text length];
NSUInteger replacementLength = [string length];
NSUInteger rangeLength = range.length;
NSUInteger newLength = oldLength - rangeLength + replacementLength;
BOOL returnKey = [string rangeOfString: #"\n"].location != NSNotFound;
return newLength <= MAXLENGTH || returnKey;
}
UPDATE: Updated to accept the return key even when at MAXLENGTH. Thanks Mr Rogers!
UPDATE
I cannot delete this answer because it is the accepted one, but it was not correct. Here is the correct code, copied from TomA below:
#define MAXLENGTH 10
- (BOOL)textField:(UITextField *) textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSUInteger oldLength = [textField.text length];
NSUInteger replacementLength = [string length];
NSUInteger rangeLength = range.length;
NSUInteger newLength = oldLength - rangeLength + replacementLength;
BOOL returnKey = [string rangeOfString: #"\n"].location != NSNotFound;
return newLength <= MAXLENGTH || returnKey;
}
ORIGINAL
I think you mean UITextField. If yes, then there is a simple way.
Implement the UITextFieldDelegate protocol
Implement the textField:shouldChangeCharactersInRange:replacementString: method.
That method gets called on every character tap or previous character replacement. in this method, you can do something like this:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
if ([textField.text length] > MAXLENGTH) {
textField.text = [textField.text substringToIndex:MAXLENGTH-1];
return NO;
}
return YES;
}
A better function which handles backspaces correctly and limits the characters to the supplied length limit is the following:
#define MAXLENGTH 8
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
int length = [textField.text length] ;
if (length >= MAXLENGTH && ![string isEqualToString:#""]) {
textField.text = [textField.text substringToIndex:MAXLENGTH];
return NO;
}
return YES;
}
Cheers!
This code limits the text while also allowing you enter characters or paste anywhere into the text. If the resulting text would be too long it changes the characters in the range and truncates the resulting text to the limit.
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
NSUInteger newLength = [textField.text length] - range.length + [string length];
if (newLength >= MAXLENGTH) {
textField.text = [[textField.text stringByReplacingCharactersInRange:range withString:string] substringToIndex:MAXLENGTH];
return NO;
}
return YES;
}
I think this code would do the trick:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range
replacementString:(NSString*)string
{
if (range.location >= MAX_LENGTH)
return NO;
return YES;
}
With this delegate method you can prevent the user to add more characters than MAX_LENGTH to your text field and the user should be allowed to enter backspaces if needed.
For me this did the magic:
if (textField.text.length >= 10 && range.length == 0)
return NO;
return YES;
this is how i resolved that problem. When max limit is reached it wont try to add more... you will only be able to remove chars
#define MAX_SIZE ((int) 5)
...
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
if ([textField.text length] >= MAX_SIZE && ![string isEqualToString:#""]) {
return NO;
}
return YES;
}
I think there's no such property.
But the text you assign to the UILabel has to be an NSString. And before you assign this string to the UILabel's text property you can for example use the following method of NSString to crop the string at a given index (your maxlength):
- (NSString *)substringToIndex:(NSUInteger)anIndex
This is similar to coneybeare's answer, but now the text field can contain a maximum of MAXLENGTH symbols:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
if ([textField.text length] > MAXLENGTH - 1) {
textField.text = [textField.text substringToIndex:MAXLENGTH];
return NO;
}
return YES;
}
You have to be aware of the location the text is placed in as well as the length of text being added (in case they're pasting more than one character). The pattern between these with respect to max length is that their sum should never exceed the max length.
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSInteger locationAndStringLengthSum = range.location + [string length];
if ([textField isEqual:_expirationMonthField]) {
if (locationAndStringLengthSum > EXP_MONTH_FIELD_MAX_CHAR_LENGTH) {
return NO;
}
}
else if ([textField isEqual:_expirationYearField]) {
if (locationAndStringLengthSum > EXP_YEAR_FIELD_MAX_CHAR_LENGTH) {
return NO;
}
}
else if ([textField isEqual:_securityCodeField]) {
if (locationAndStringLengthSum > SECURITY_FIELD_MAX_CHAR_LENGTH) {
return NO;
}
}
else if ([textField isEqual:_zipCodeField]) {
if (locationAndStringLengthSum > ZIP_CODE_MAX_CHAR_LENGTH) {
return NO;
}
}
return YES;
}
You need to assign delegate on ViewDidLoad
TextFieldname.delegate=self
I have a bitmap font which which doesn't have every single character, such as accented characters (é î ü etc) or symbols such as "¥" or © which I'm using to display usernames in a Highscore table for a game.
Is it possible to limit the UIKit keyboard to certain characters, or only allow certain characters in the UITextField? Or will I have to roll my own input mechanism? I'm thinking and old school, Arcade style, one letter at a time "thing" would be ok.
Using the UITextFieldDelegate method mentioned by intregus, you can do this quite easily:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
// Only characters in the NSCharacterSet you choose will insertable.
NSCharacterSet *invalidCharSet = [[NSCharacterSet characterSetWithCharactersInString:#"abcdefgABCDEFG"] invertedSet];
NSString *filtered = [[string componentsSeparatedByCharactersInSet:invalidCharSet] componentsJoinedByString:#""];
return [string isEqualToString:filtered];
}
You could try using the following UITextFieldDelegate method:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string;
try using the UIKeyboardTypeNamePhonePad for your UITextField. It only has letters and numbers on it:
textField.keyboardType = UIKeyboardTypeNamePhonePad;
Using Interface builder you can link and get the event for "Editing changed" in any of your function. Now there you can put check for the length
- (IBAction)onValueChange:(id)sender
{
NSString *text = nil;
int MAX_LENGTH = 20;
switch ([sender tag] )
{
case 1:
{
text = myEditField.text;
if (MAX_LENGTH < [text length]) {
myEditField.text = [text substringToIndex:MAX_LENGTH];
}
}
break;
default:
break;
}
}