Backspace many characters in a row in a UITextView - iphone

Question

I want to check if a user backspaces a character in a textView if there are any of that same character connecting it for it to delete them all...
For example if the character I'm checking for is "e" I have the text "easy heeeeeello" and the user starts hitting backspace it will become:
easy heeeeeello -> easy heeeeeell -> easy heeeeeel -> easy heeeeee -> easy h
The code should detect that a backspace was pressed.
Then it will detect which text is going to be deleted, and if that text is a character (in our case "e") it will check if there are more "e"s touching that "e" creating a strand of "e"s and delete them all.
Can you help me?

Answer 1

OK, so I wrote this code, and it works for me
-(BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text {
if([text isEqualToString:#""]) {
//Detected backspace character as the new character is #"" meaning something will be deleted
char toDelete = [textView.text characterAtIndex:range.location];
int duplicateCharCount = 0;
for(int i =range.location-1; i>=0; i--) {
if([textView.text characterAtIndex:i] == toDelete) {
duplicateCharCount++;
} else {
break;
}
}
NSRange newRange = NSMakeRange(0, range.location - duplicateCharCount);
[textView setText:[textView.text substringWithRange:newRange]];
return NO;
} else {
return YES;
}
}
I know its not the best implementation, but now you know how to proceed
Hope this helps

Answer 2

Kind of fun, so I wrote the code just now.
The code works.
First, we should set the UITextView's delegate and respond to .
textView:shouldChangeTextInRange:replacementText:
According to the document,
If the user presses the Delete key, the length of the range is 1 and an empty string object replaces that single character.
So the code comes below :
#pragma mark -
#pragma mark - UITextView Delegate
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
static NSString *suffix = #"e";
if (range.length == 1 && [text length] == 0) {
// The user presses the Delete key.
NSString *currentText = [textView.text substringToIndex:range.location+1];
NSString *appendingText = [textView.text substringFromIndex:range.location+1];
if ([currentText hasSuffix:suffix]) {
NSRange range = [self inverseRangeOfString:currentText withSuffix:suffix];
currentText = [currentText stringByReplacingCharactersInRange:range withString:#""];
textView.text = [currentText stringByAppendingString:appendingText];
return NO;
}
}
return YES;
}
- (NSRange)inverseRangeOfString:(NSString *)str withSuffix:(NSString *)suffix
{
int length = [str length];
int lastIndex = length - 1;
int cnt = 0;
for (; lastIndex >= 0; --lastIndex) {
NSString *subStr = [str substringFromIndex:lastIndex];
if ([subStr hasPrefix:suffix]) {
cnt++;
} else {
break;
}
}
NSRange range = (NSRange){++lastIndex, cnt};
return range;
}