iOS实现输入框跟随键盘自动上移的实例代码

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];

- (void)keyboardWillShow:(NSNotification *)notification
{
  //获取处于焦点中的view
  NSArray *textFields = @[phoneNemberText, verifyCodeText];
  UIView *focusView = nil;
  for (UITextField *view in textFields) {
    if ([view isFirstResponder]) {
      focusView = view;
      break;
    }
  }
  if (focusView) {
    //获取键盘弹出的时间
    double duration = [notification.userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];
    //获取键盘上端Y坐标
    CGFloat keyboardY = [userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue].origin.y;
    //获取输入框下端相对于window的Y坐标
    CGRect rect = [focusView convertRect:focusView.bounds toView:[[[UIApplication sharedApplication] delegate] window]];
    CGPoint tmp = rect.origin;
    CGFloat inputBoxY = tmp.y + focusView.frame.size.height;
    //计算二者差值
    CGFloat ty = keyboardY - inputBoxY;
    NSLog(@"position keyboard: %f, inputbox: %f, ty: %f", keyboardY, inputBoxY, ty);
    //差值小于0，做平移变换
    [UIView animateWithDuration:duration animations:^{
      if (ty < 0) {
        self.view.transform = CGAffineTransformMakeTranslation(0, ty);
      }
    }];
  }
}

- (void)keyboardWillHide:(NSNotification *)notification
{
  //获取键盘弹出的时间
  double duration = [notification.userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];
  //还原
  [UIView animateWithDuration:duration animations:^{
    self.view.transform = CGAffineTransformMakeTranslation(0, 0);
  }];
}

- (CGFloat)getKeyboardY:(NSDictionary *)userInfo
{
  CGFloat screenHeight;
  CGFloat keyboardY = 0;
  CGFloat keyboardHeight = 0;
  UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;
  if (( [[[UIDevice currentDevice] systemVersion] floatValue]<8) && UIInterfaceOrientationIsLandscape(orientation))
  {
    screenHeight = [[UIScreen mainScreen] bounds].size.width;
    keyboardHeight = [userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue].size.width;
    keyboardY = screenHeight - keyboardHeight;
  }
  else if (( [[[UIDevice currentDevice] systemVersion] floatValue]<8) && UIInterfaceOrientationIsPortrait(orientation)) {
    screenHeight = [[UIScreen mainScreen] bounds].size.height;
    keyboardHeight = [userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue].size.height;
    keyboardY = screenHeight - keyboardHeight;
  }
  else {
    keyboardY = [userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue].origin.y;
  }
  return keyboardY;
}

- (CGPoint)getViewOriginPointToWindow:(UIView *)view
{
  CGPoint origin;
  if ([[[UIDevice currentDevice] systemVersion] floatValue] < 8) {
    CGPoint focusViewPoint = [view convertPoint:CGPointZero toView:nil];
    UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;
    if (orientation == UIInterfaceOrientationLandscapeLeft) {
      origin.y = focusViewPoint.x;
      origin.x = [[[UIApplication sharedApplication] delegate] window].bounds.size.height - focusViewPoint.y;
    }
    else if (orientation == UIInterfaceOrientationLandscapeRight) {
      origin.y = [[[UIApplication sharedApplication] delegate] window].bounds.size.width - focusViewPoint.x;
      origin.x = focusViewPoint.y;
    }
    else if (orientation == UIInterfaceOrientationPortraitUpsideDown) {
      origin.y = [[[UIApplication sharedApplication] delegate] window].bounds.size.height - focusViewPoint.y;
      origin.x = [[[UIApplication sharedApplication] delegate] window].bounds.size.width - focusViewPoint.x;
    }
    else {
      origin = focusViewPoint;
    }
  }
  else {
    CGRect rect = [view convertRect:view.bounds toView:[[[UIApplication sharedApplication] delegate] window]];
    origin = rect.origin;
  }
  return origin;
}

//获取键盘上端Y坐标
CGFloat keyboardY = [self getKeyboardY:notification.userInfo];
//获取输入框下端相对于window的Y坐标
CGPoint tmp = [self getViewOriginPointToWindow:focusView];
CGFloat inputBoxY = tmp.y + focusView.frame.size.height;