sample class

hello.rb

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class TestInput : MonoBehaviour
{
    private Image image;
    private Vector2 initPosition;
    private InputField inputField;
    private bool isActive = false;

    private void Start()
    {
        image = GetComponent<Image>();
        inputField = GetComponentInChildren<InputField>();
        initPosition = image.rectTransform.anchoredPosition;
    }

    private void Update()
    {
        if(!isActive && this.inputField.isFocused)
        {
            isActive = true;
            InputStart();
        }

        if(isActive && !this.inputField.isFocused)
        {
            isActive = false;
            InputEnd();
        }
    }

    public void InputStart()
    {
        TouchScreenKeyboard.hideInput = false;
        float height = TouchScreenKeyboard.area.height;
        Debug.Log("height >> " + height);
        image.rectTransform.anchoredPosition = Vector2.up * height;
    }

    public void InputEnd()
    {
        image.rectTransform.anchoredPosition = initPosition;
    }
}