Fullscreen game view in Unity

readme.md

Taken from https://www.reddit.com/r/Unity3D/comments/2lymim/full_full_screen_on_play_script_freebie_for/

https://www.assetstore.unity3d.com/en/#!/content/25045

FullscreenPlayMode.cs

using UnityEditor;
using UnityEngine;
using System.Collections;

[InitializeOnLoad]
public class FullscreenPlayMode : MonoBehaviour {

//The size of the toolbar above the game view, excluding the OS border.
private static int tabHeight = 22;

static FullscreenPlayMode()
{
    EditorApplication.playmodeStateChanged -= CheckPlayModeState;
    EditorApplication.playmodeStateChanged += CheckPlayModeState;

}

static void CheckPlayModeState()
{
    if (EditorApplication.isPlaying)
    {
        FullScreenGameWindow();
    }
    else 
    {
        CloseGameWindow();
    }
}

static EditorWindow GetMainGameView(){
    EditorApplication.ExecuteMenuItem("Window/Game");

    System.Type T = System.Type.GetType("UnityEditor.GameView,UnityEditor");
    System.Reflection.MethodInfo GetMainGameView = T.GetMethod("GetMainGameView",System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Static);
    System.Object Res = GetMainGameView.Invoke(null,null);
    return (EditorWindow)Res;
}

static void FullScreenGameWindow(){

    EditorWindow gameView = GetMainGameView();

    gameView.title = "Game (Stereo)";
    Rect newPos = new Rect(0, 0 - tabHeight, Screen.currentResolution.width, Screen.currentResolution.height + tabHeight);

    gameView.position = newPos;
    gameView.minSize = new Vector2(Screen.currentResolution.width, Screen.currentResolution.height + tabHeight);
    gameView.maxSize = gameView.minSize;
    gameView.position = newPos; 

}

static void CloseGameWindow(){
    EditorWindow gameView = GetMainGameView();
    gameView.Close();
} 
}

this solution is not work fine with unity 2018 now ,what should i do as i an a newber??

how to exit full gameview -_-

For 2020 there is this semi-working gist https://gist.github.com/fnuecke/d4275087cc7969257eae0f939fac3d2f