首先,汉字的输入时的联想词在输入到TextFiled时,并不会走
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string;
这导致了在这里进行长度限制的代码都会失效.此路不通.
因此我们可以用注册UITextFieldTextDidChangeNotification通知来监测TextField的文字的变化：
1、注册通知
[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(textFiledEditChanged:) name:@"UITextFieldTextDidChangeNotification" object:myTextField];
2、实现 textFiledEditChanged: 方法
- (void) textFiledEditChanged:(NSNotification *)notification{ UITextField *textField = (UITextField *)obj.object; NSString *toBeString = textField.text; //获取高亮部分 UITextRange *selectedRange = [textField markedTextRange]; UITextPosition *position = [textField positionFromPosition:selectedRange.start offset:0]; // 没有高亮选择的字，则对已输入的文字进行字数统计和限制 if (!position || !selectedRange) { if (toBeString.length > MAX_STARWORDS_LENGTH) { NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:MAX_STARWORDS_LENGTH]; if (rangeIndex.length == 1) { textField.text = [toBeString substringToIndex:MAX_STARWORDS_LENGTH]; } else { NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(0, MAX_STARWORDS_LENGTH)]; textField.text = [toBeString substringWithRange:rangeRange]; } } } }
至此，可以完美控制输入字符长度
原文：https://www.cnblogs.com/MasterPeng/p/9692721.html