InputField.isFocused

説明

InputField は現在フォーカスが当たっていて、イベントを処理することができます。

using UnityEngine;
using System.Collections;
using UnityEngine.UI; // Required when Using UI elements.

public class Example : MonoBehaviour 
{
	public GameObject mainInputField;

	void Update()
	{
		//If the input field is focused, change its color to green.
		if (mainInputField.GetComponent<InputField>().isFocused == true) 
		{
			mainInputField.GetComponent<Image>().color = Color.green;
		}
	}
}