ios - 出现iOS键盘时如何向上移动 View ？

Question

对于只有三个文本字段和提交按钮的登录屏幕，我希望当键盘出现时 View 向上移动，这样当字段没有隐藏时，它也不会向上移出 View 。

所需的移动量使得提交按钮在键盘上方有固定距离。虽然可以通过将字段移到页面的高处为键盘留出空间，但提交按钮仍然隐藏

我尝试只添加以下内容:

-(void) viewWillAppear:(BOOL)Animated {
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
    
}
- (void)viewWillDisappear:(BOOL)animated {
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}

这会将 View 向上移动一个固定的量，但移动量太大以至于无法编辑字段，即它们太高了。

建议的另一个 SO 答案:

-(void)textFieldDidBeginEditing:(UITextField *)textField
{
    [self animateTextField:textField up:YES];
}

- (void)textFieldDidEndEditing:(UITextField *)textField
{
    [self animateTextField:textField up:NO];
}

-(void)animateTextField:(UITextField*)textField up:(BOOL)up
{
    const int movementDistance = -200; // tweak as needed
    const float movementDuration = 0.3f; // tweak as needed
    
    int movement = (up ? movementDistance : -movementDistance);
    
    [UIView beginAnimations: @"animateTextField" context: nil];
    [UIView setAnimationBeginsFromCurrentState: YES];
    [UIView setAnimationDuration: movementDuration];
    self.view.frame = CGRectOffset(self.view.frame, 0, movement);
    [UIView commitAnimations];
}

我不知道如何实现它。如果你只是保持原样，什么也不会发生。我猜你应该用你的文本字段的名称重命名文本字段，但在那种情况下，你会为​​每个文本字段都这样做吗？我无法让它产生任何效果。

另一个建议是使用诸如 TPKeyboardAvoiding 之类的类别，但这需要我在这种情况下不需要的 ScrollView 。

这个问题在2015年没有直接的解决方案吗？

Answer 1

当用户开始输入时，以下动画会将您的 View (在本例中为 viewForLogin)移动到上方 200 像素。当文本字段结束编辑时， View 将动画回到原始位置。不要忘记为文本字段设置委托(delegate)。

swift 3

func textFieldDidBeginEditing(_ textField: UITextField) {
    UIView.animate(withDuration: 0.3, animations: {
        self.view.frame = CGRect(x:self.view.frame.origin.x, y:self.view.frame.origin.y - 200, width:self.view.frame.size.width, height:self.view.frame.size.height);

    })
}

func textFieldDidEndEditing(_ textField: UITextField) {
    UIView.animate(withDuration: 0.3, animations: {
        self.viewSupport.frame = CGRect(x:self.viewSupport.frame.origin.x, y:self.viewSupport.frame.origin.y + 200, width:self.viewSupport.frame.size.width, height:self.viewSupport.frame.size.height);

    })
}

objective-C

-(void)textFieldDidBeginEditing:(UITextField *)textField
{
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:.3];
    [UIView setAnimationBeginsFromCurrentState:TRUE];
    self.view.frame = CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y -200., self.view.frame.size.width, self.view.frame.size.height);

    [UIView commitAnimations];


}


-(void)textFieldDidEndEditing:(UITextField *)textField
{
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:.3];
    [UIView setAnimationBeginsFromCurrentState:TRUE];
    self.view.frame = CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y +200., self.view.frame.size.width, self.view.frame.size.height);

    [UIView commitAnimations];

}