監聽UITextField的text的改變
阿新 • • 發佈:2019-02-13
大概有以下幾種方法:
UITextField的代理方法:shouldChangeChractersInRange
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string { //Replace the string manually in the textbox textField.text = [textField.text stringByReplacingCharactersInRange:range withString:string]; //perform any logic here now that you are sure the textbox text has changed [self didChangeTextInTextField:textField]; return NO; //this make iOS not to perform any action }
使用addTarget:
[textField addTarget:self action:@selector(textFieldDidChange:) forControlEvents:UIControlEventEditingChanged];
使用UITextFieldTextDidChangeNotification通知
使用kVO
[myUITextField addObserver:self forKeyPath:@"text" options:NSKeyValueObservingOptionNew|NSKeyValueObservingOptionOld context:myContext];
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context { if(context == myContext) { //Here you get notified every time myUITextField's "text" property is updated NSLog(@"New value: %@ - Old value: %@", [change objectForKey:NSKeyValueChangeNewKey], [change objectForKey:NSKeyValueChangeOldKey]); } else [super observeValueForKeyPath:keyPath ofObject:object change:change context:context]; }