How to find a particular text in UITextField? - objective-c

Question

In my iPhone app I have a UITextField ans text field value is being taken into an NSString, I want to find if a particular character " is typed in that
How can I do that?
UITextField *textField;
NSString *String=textField.text;
-(IBAction)FindCharecter:(id)sender
{
// if String Contain ",then i wish to print #"Found symbol"
}

Answer 1

UITextField *textField;
NSString *string=textField.text;
if ([string rangeOfString:#"\""].location == NSNotFound) {
NSLog(#"string does not \"");
} else {
NSLog(#"string contains \"");
}
check this

Answer 2

Try This:
-(IBAction)FindCharecter:(id)sender
{
// if String Contain ",then i wish to print #"Found symbol"
if ([String rangeOfString:#"\""].location != NSNotFound) {
NSLog(#"Found");
}
else{
NSLog(#"Not Found");
}
}

Answer 3

Implement the following delegate of UITextField
-(NSString *)ValidateSearchString:(NSString *) aString{
NSCharacterSet * set = [[NSCharacterSet characterSetWithCharactersInString:#"YourString"] invertedSet];
if ([aString rangeOfCharacterFromSet:set].location != NSNotFound) {
return #"Not Found";
}
return #"Found";;
}
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
NSLog("particular character %#",[self ValidateSearchString:string]);
// string will contain the particular character typed;
return YES;
}

Answer 4

You need to confirm and implement UITextFieldDelegate protocol.
1) If you want to check for a pattern on the go (when user typing itself), you need to implement
- (BOOL)textField:(UITextField *)textField
shouldChangeCharactersInRange:(NSRange)range
replacementString:(NSString *)string
2) If you want to check when user completed typing, you may want to implement
- (void)textFieldDidEndEditing:(UITextField *)textField
Now to do the actual comparison process
if([textFieldString rangeOfString:#"YOUR_COMPARISON_STRING"].location == NSNotFound){
//your pattern is not typed yet
}else{
//There it is..
}

Answer 5

You can use shouldChangeCharactersInRange delegate method for this.
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if([string isEqualToString:#"\""])
{
NSLog(#"Entered \" ");
}
}
Or you can use: rangeOfString of NSString class.
if ([textField.text rangeOfString:#"\""].location == NSNotFound)
{
NSLog(#"Entered \" ");
}
For reference:
textField:shouldChangeCharactersInRange:replacementString:
Asks the delegate if the specified text should be changed.
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
Parameters
textField
The text field containing the text.
range
The range of characters to be replaced
string
The replacement string.
Return Value
YES if the specified text range should be replaced; otherwise, NO to
keep the old text. Discussion
The text field calls this method whenever the user types a new
character in the text field or deletes an existing character.
Availability
Available in iOS 2.0 and later.
UITextFieldDelegate
rangeOfString:
Finds and returns the range of the first occurrence of a given string
within the receiver.
- (NSRange)rangeOfString:(NSString *)aString
Parameters
aString
The string to search for. This value must not be nil.
Important: Raises an NSInvalidArgumentException if aString is nil.
Return Value
An NSRange structure giving the location and length in the receiver of
the first occurrence of aString. Returns {NSNotFound, 0} if aString is
not found or is empty (#"").
Discussion
Invokes rangeOfString:options: with no options.
This method detects all invalid ranges (including those with negative
lengths). For applications linked against OS X v10.6 and later, this
error causes an exception; for applications linked against earlier
releases, this error causes a warning, which is displayed just once
per application execution. Availability
Declared In NSString.h
Declared In UITextField.h
NSString Class