uitextfielddelegate | 易学教程

How to detect delete key on an UITextField in iOS 8?

阅读更多关于 How to detect delete key on an UITextField in iOS 8?

问题 I have subclassed UITextField and implemented the UIKeyInput protocol's deleteBackward method to detect backspace being pressed. This works fine on iOS 7 but not on iOS 8. deleteBackward is not called on the UITextField anymore when I press the backspace key. I've checked the documentation and the release notes and nothing points to the reason why this could happen. Any pointers? 回答1: You must look an example for MBContactPicker on github. Deletion of contacts at MBContactPicker via Backspace

Allow only alphanumeric characters for a UITextField

阅读更多关于 Allow only alphanumeric characters for a UITextField

How would I go about allowing inputting only alphanumeric characters in an iOS UITextField ? Use the UITextFieldDelegate method -textField:shouldChangeCharactersInRange:replacementString: with an NSCharacterSet containing the inverse of the characters you want to allow. For example: // in -init, -initWithNibName:bundle:, or similar NSCharacterSet *blockedCharacters = [[[NSCharacterSet alphanumericCharacterSet] invertedSet] retain]; - (BOOL)textField:(UITextField *)field shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)characters { return ([characters

Allow only alphanumeric characters for a UITextField

阅读更多关于 Allow only alphanumeric characters for a UITextField

问题 How would I go about allowing inputting only alphanumeric characters in an iOS UITextField ? 回答1: Use the UITextFieldDelegate method -textField:shouldChangeCharactersInRange:replacementString: with an NSCharacterSet containing the inverse of the characters you want to allow. For example: // in -init, -initWithNibName:bundle:, or similar NSCharacterSet *blockedCharacters = [[[NSCharacterSet alphanumericCharacterSet] invertedSet] retain]; - (BOOL)textField:(UITextField *)field

UITextField text change event

阅读更多关于 UITextField text change event

问题 How can I detect any text changes in a textField? The delegate method shouldChangeCharactersInRange works for something, but it did not fulfill my need exactly. Since until it returns YES, the textField texts are not available to other observer methods. e.g. in my code calculateAndUpdateTextFields did not get the updated text, the user has typed. Is their any way to get something like textChanged Java event handler. - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange: