android 通过java层重载返回键事件onBackPressed有bug，有时候不响应！！！
@Override
public void onBackPressed(){
Log.v("life","onBackPressed");
super.onBackPressed();
UnityPlayer.UnitySendMessage(GameObjectName, OnBackMethodName,"back");
}
解决方案：在unity中获取KeyCode.Escape点击事件，android返回键就是KeyCode.Escape点击事件,这个没有问题
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.SceneManagement;
public class GameApp : MonoBehaviour {
void Update () {
//Debug.Log("Update^^^^^^^^^^^^^");
_luaMgr.Update();
if (Input.GetKeyDown(KeyCode.Escape))
{
Dg.Log("Input.GetKeyDown:::KeyCode.Escape");
}
}
}
