iOS積累--textField擷取鍵盤高度以及限制字數

擷取鍵盤:

方法: 增加監聽, 當鍵盤出現或改變時收到消息

注意:需要在dealloc裡面登出通知

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil]; //鍵盤将要出現時響應

 [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];// 鍵盤将要退出時響應
           

// 當鍵盤出現或改變時調用
- (void)keyboardWillShow:(NSNotification *)nofi{
    // 擷取鍵盤高度
    NSDictionary *userInfo = [nofi userInfo];
    NSValue *value = [userInfo objectForKey:UIKeyboardFrameEndUserInfoKey];
    CGRect keyboardRect = [value CGRectValue];
    int height = keyboardRect.size.height;
}
           

限制字數

// 直接給textfield增加監聽
    [self.nameTF addTarget:self action:@selector(textFieldDidChange:) forControlEvents:UIControlEventEditingChanged];
           

方法:

// 限制文字輸入
-(void)textFieldDidChange:(UITextField *)textField{
    NSString *toBeString = textField.text;
    // 鍵盤輸入模式
    //擷取高亮部分
    UITextRange *selectedRange = [textField markedTextRange];UITextPosition *position = [textField positionFromPosition:selectedRange.start offset:];
    // 沒有高亮選擇的字，則對已輸入的文字進行字數統計和限制
    if (!position) {
        if (toBeString.length > MAX_STARWORDS_LENGTH) {
            NSRange rangeIndex = [toBeString rangeOfComposedCharacterSequenceAtIndex:MAX_STARWORDS_LENGTH];
            if (rangeIndex.length == ) { textField.text = [toBeString substringToIndex:MAX_STARWORDS_LENGTH];
            } else { NSRange rangeRange = [toBeString rangeOfComposedCharacterSequencesForRange:NSMakeRange(, MAX_STARWORDS_LENGTH)];
                textField.text = [toBeString substringWithRange:rangeRange];
            }
        }
    }
}
           

參考部落格: http://www.jianshu.com/p/2d1c06f2dfa4