[HELP] C# GUI, not showing up in camera

Hello everyone, im new to unity and C# please help. The GUI layout, label and buttons are not showing up when i drag them to camera or deploy it on an android phone. The script is written in C# and I want to develop an android application that use this 2 scripts The code is below. Anyone, Please help me in this problem. I will appreciate any HELP. please try give a solution to this, i need your expertise please.

     using UnityEngine;
     using System;
     using System.Collections;
     
     public class Example : MonoBehaviour {
         
         private string [] LocalizedStrings;
         
         private static TTSBridge ttsengine;
         
         public Font unicodearial;
     
         string thetext = "Awesome dude! Input a phrase to speech.\n You can use enter to make a new line.\nTry something!";
         int retval;
         string deviceLanguage ="";
         string TTSLanguage ="";
         //string TTSLanguages="";
         
         float thepitch = 1.0f;
         float oldpitch = 1.0f;
         float therate = 1.0f;
         float oldrate = 1.0f;    
         
         
         #if UNITY_ANDROID
         void Start () {
             
             AndroidJNI.AttachCurrentThread();        
     
             // Retrieve device current language
             using (AndroidJavaClass cls = new AndroidJavaClass("java.util.Locale")) {
                 using (AndroidJavaObject locale = cls.CallStatic<AndroidJavaObject>("getDefault")) {                
                     deviceLanguage = locale.Call<string>("getDisplayLanguage");
                 }
             }        
             // Startup vibration Java object
             ttsengine = new TTSBridge();
             ttsengine.Init();
     
             
         }
         #endif
         void OnGUI() {
             
             GUI.color = Color.white;
              GUI.skin.font = unicodearial;
             GUILayout.BeginArea(new Rect(20, 10, Screen.width-40, Screen.height-80));
             GUILayout.Label("Android Native TTS engine plugin example demo");
             GUILayout.Space(10.0f);            
             GUILayout.Label("device language:"+deviceLanguage);
             GUILayout.Space(10.0f);
             GUILayout.Label("TTS engine language:"+TTSLanguage);
             
             if(ttsengine.isInitialized())
                 TTSLanguage = ttsengine.GetLanguage();
             
             if(GUILayout.Button("Switch to english", GUILayout.Height(40)))
             {
     #if UNITY_ANDROID
                 retval = ttsengine.SetLanguage("inglese");
                 Debug.Log( "setLanguage(US) returned: "+retval);
     #endif            
             }
             GUILayout.Space(10.0f);
             if(GUILayout.Button("Switch to "+deviceLanguage+"(default)", GUILayout.Height(40)))
             {
     #if UNITY_ANDROID
                 retval=ttsengine.SetLanguage("italiano");
                 Debug.Log( "setLanguage(ITA) returned: "+retval);
     #endif            
             }
             
             GUILayout.Space(40.0f);
     
             GUILayout.Label("Set pitch: "+thepitch);
             thepitch = GUILayout.HorizontalSlider(thepitch,0.1f,2.0f, GUILayout.Height(50));
             if (thepitch!=oldpitch)
             {
                 oldpitch=thepitch;
     #if UNITY_ANDROID
                 ttsengine.SetPitch(thepitch);
     #endif            
             }
             
             
             GUILayout.Space(30.0f);
             GUILayout.Label("Set speed: "+therate);
             therate = GUILayout.HorizontalSlider(therate,0.5f,2.0f, GUILayout.Height(50));
             if (therate!=oldrate)
             {
                 oldrate=therate;
     #if UNITY_ANDROID
                 retval=ttsengine.SetSpeechRate(therate);        
     #endif
             }
     
             GUILayout.Space(20.0f);
             
             thetext = GUILayout.TextArea( thetext, 200 );
             GUILayout.Space(20.0f);
             if(GUILayout.Button("TALK", GUILayout.Height(80)))
             {
                 // talk
     #if UNITY_ANDROID
                 ttsengine.Speak(thetext.ToLower());
     #endif
             }
             GUILayout.Space(30.0f);
             GUILayout.EndArea();
             GUI.Label(new Rect(0,Screen.height-40,Screen.width,40),"Litobyte Softworks - Native TTS engine plugin v 1.1.0");
             
         }
         
         void OnApplicationQuit()
         {
             #if UNITY_ANDROID
             ttsengine.Dispose();
             #endif
         }    
     
     }

this is the TTSBRIDGE script the first script(Example.cs) is refering to

using UnityEngine; using System; using System.Collections;

public class TTSBridge : IDisposable {

 private AndroidJavaClass cls_SpeechActivity = new AndroidJavaClass("com.unity3d.Plugin.AndroidTTSActivity");
 
 public void Init() {
     using (AndroidJavaClass cls_UnityPlayer = new AndroidJavaClass("com.unity3d.player.UnityPlayer")) {
         using (AndroidJavaObject obj_Activity = cls_UnityPlayer.GetStatic<AndroidJavaObject>("currentActivity")) {
                 cls_SpeechActivity.CallStatic("Init", obj_Activity);
         }
     }
 }
 
 public bool isInitialized() {
     return cls_SpeechActivity.CallStatic<bool>("engineInitialized");
 }
 
 public void Speak(string Text) {
     cls_SpeechActivity.CallStatic("Speak", Text);
 }
 
 public bool isSpeaking() {
     return cls_SpeechActivity.CallStatic<bool>("isSpeaking");
 }
 
 public int SetPitch(float thepitch)
 {
     return cls_SpeechActivity.CallStatic<int>("setPitch", thepitch);    
 }
 public int SetSpeechRate(float therate)
 {
     return cls_SpeechActivity.CallStatic<int>("setSpeechRate", therate);    
 }    
 public int SetLanguage(string Text) {
     return cls_SpeechActivity.CallStatic<int>("setLanguage", Text );
 }
 public string GetLanguage() {
     return cls_SpeechActivity.CallStatic<string>("getLanguage" );
 }
 public string getAllLanguages() {
     return cls_SpeechActivity.CallStatic<string>("getAllLanguages" );
 }    
 public void Dispose() {
     cls_SpeechActivity.Dispose();
 }

please help me, I need all of you who are expert in unity thank you in advance!