Open Radar

 
On ios6 UITextFieldDelegate protocol method shouldChangeCharactersInRange reports a range length of 1 when you backspace text on the Pinyin keyboard. On ios7 range length is the length of the "selected" markedTextRange multistage text input.

Steps to Reproduce:
1. Create a simple project in XCode5 with a single textbox
2. Add UITextFieldDelegate shouldChangeCharactersInRange

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    NSLog(@" location:%lu length:%lu ", (unsigned long)range.location, (unsigned long)range.length);
    return true;
}

3. Launch app on ios6 simulator.  Set your keyboard to "Chinese Simplified Pinyin.

4. On ios6 type "banana", press backspace 6 times to remove the text. Logged results:
string b location:0 length:0 
string a location:1 length:0 
string n location:2 length:0 
string a location:3 length:0 
string n location:4 length:0 
string a location:5 length:0 
string  location:5 length:1 
string  location:4 length:1 
string  location:3 length:1 
string  location:2 length:1 
string  location:1 length:1 
string  location:0 length:1

6. Repeat above step on ios7. Ensure keyboard is "Chinese Simplified Pinyin.
string b location:0 length:0 
string a location:1 length:0 
string n location:2 length:0 
string a location:3 length:0 
string n location:5 length:0 
string a location:6 length:0 
string  location:0 length:6 
string  location:0 length:6 
string  location:0 length:5 
string  location:0 length:3 
string  location:0 length:2 
string  location:0 length:1 

4. Note the difference in length values in ios7

Expected Results:
Consistent values for range length between ios6 and ios7

Actual Results:
ios7 appears to be reporting the markedTextRange multistage text input.