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== Testing ''chars'' entered by users in ''NSTextField'' == == Testing ''chars'' entered by users in ''NSTextField'' ==
-(just for the case if someone else has the same problem)+When the contents of a NSTextField are changed by the user, it is possible to check whether or not to accept the changes.
1. Subclass NSTextField 1. Subclass NSTextField
-2. In your subclass adopt the+2. In your subclass implement the
- (BOOL) textView: (NSTextView*) textView - (BOOL) textView: (NSTextView*) textView
shouldChangeTextInRange: (NSRange) range shouldChangeTextInRange: (NSRange) range
Line 10: Line 10:
method. method.
-3. In this method you can access to the ''replacementString'' as ''char'' with the following line:+3. Within this method you can access to the ''replacementString'' as an NSString, or as ''char'' with the following line:
char c = *([replacementString cString] + 0); char c = *([replacementString cString] + 0);
-4. Then you are free to examinate the conditions...+4. You should return YES or NO depending on whether you accept the replacement string.
== Limiting text input length in ''NSTextField'' == == Limiting text input length in ''NSTextField'' ==
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1. Subclass NSTextField 1. Subclass NSTextField
-2. In your subclass adopt the+2. In your subclass implement the
- (BOOL) textView: (NSTextView*) textView - (BOOL) textView: (NSTextView*) textView
shouldChangeTextInRange: (NSRange) range shouldChangeTextInRange: (NSRange) range
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method. method.
-3. Create an instance variable setting method:+3. Also create an instance variable setting method:
- (void) setMaxLength: (int) ml - (void) setMaxLength: (int) ml
{ {
Line 32: Line 32:
} }
-4. Then fill your method 2. with this:+4. Then fill your implementation of textView:shouldChangeTextInRange:replacementString: with the following code:
int newLength; int newLength;
/* The exact change isn't known. Disallow the change to be safe. */ /* The exact change isn't known. Disallow the change to be safe. */

Revision as of 17:03, 28 June 2005

Testing chars entered by users in NSTextField

When the contents of a NSTextField are changed by the user, it is possible to check whether or not to accept the changes.

1. Subclass NSTextField

2. In your subclass implement the

        - (BOOL) textView: (NSTextView*) textView
        shouldChangeTextInRange: (NSRange) range
        replacementString: (NSString*) replacementString

method.

3. Within this method you can access to the replacementString as an NSString, or as char with the following line:

        char c = *([replacementString cString] + 0);  

4. You should return YES or NO depending on whether you accept the replacement string.

Limiting text input length in NSTextField

(based on Alexander Malmberg's snippet)

1. Subclass NSTextField

2. In your subclass implement the

        - (BOOL) textView: (NSTextView*) textView
        shouldChangeTextInRange: (NSRange) range
        replacementString: (NSString*) replacementString

method.

3. Also create an instance variable setting method:

         - (void) setMaxLength: (int) ml
         {
            maxLength = ml;
         } 

4. Then fill your implementation of textView:shouldChangeTextInRange:replacementString: with the following code:

         int newLength;
         /* The exact change isn't known. Disallow the change to be safe. */
          if (range.location == NSNotFound)
               return NO;
          newLength=[[textView textStorage] length]+[replacementString length]-range.length;
          if (newLength>maxLength)
               return YES; //allowing
          else
               return NO; // not allowing