undo button

Assets/BallonHandler.cs

@@ -21,7 +21,7 @@ void OnCollisionEnter(Collision col)
     {
         if(col.gameObject.name.Contains("Bolt"))
         {
-            bhandler.PopBallon(1);
+            bhandler.PopBallon(1, gameObject);
             gameObject.SetActive(false);
             ballonAudio.Play(0);
         }
@@ -31,7 +31,7 @@ void OnTriggerEnter(Collider col)
     {
         if (col.gameObject.name.Contains("Bolt"))
         {
-            bhandler.PopBallon(1);
+            bhandler.PopBallon(1, gameObject);
             gameObject.SetActive(false);
             ballonAudio.Play(0);
         }

Assets/BallonImageHandler.cs

@@ -12,6 +12,7 @@ public class BallonImageHandler : MonoBehaviour {
     public Text console;
     public TextMeshPro front;
     public TextMeshPro back;
+    public List<GameObject> ballons;
 
     private const int level1BallonsTotal = 10;
 
@@ -22,7 +23,7 @@ public class BallonImageHandler : MonoBehaviour {
 
     // Use this for initialization
     void Start () {
-		
+        ballons = new List<GameObject>();
 	}
 
 	// Update is called once per frame
@@ -50,9 +51,10 @@ void Update ()
         }
     }
 
-    public void PopBallon(int level)
+    public void PopBallon(int level, GameObject ballon)
     {
         level1Ballons++;
+        ballons.Add(ballon);
 
         if(level == 1 && level1Ballons == 1)
         {
@@ -83,10 +85,26 @@ void ResetGame()
             child.gameObject.SetActive(true);
         }
 
+        ballons = new List<GameObject>();
         gameStarted = false;
         gameTime = 0.0F;
         level1Ballons = 0;
+
     }
 
+    public void Undo()
+    {
+        if(gameStarted)
+        {
+            int index = ballons.Count;
+
+            if(index > 0)
+            {
+                ballons[index - 1].SetActive(true);
+                ballons.Remove(ballons[index - 1]);
+                level1Ballons--;
+            }
+        }
+    }
 
 }

Assets/Scenes/MainScene.unity

@@ -9627,6 +9627,7 @@ GameObject:
   - component: {fileID: 1159778320}
   - component: {fileID: 1159778319}
   - component: {fileID: 1159778318}
+  - component: {fileID: 1159778321}
   m_Layer: 5
   m_Name: UndoButton
   m_TagString: Untagged
@@ -9728,6 +9729,19 @@ CanvasRenderer:
   m_PrefabInternal: {fileID: 0}
   m_GameObject: {fileID: 1159778316}
   m_CullTransparentMesh: 0
+--- !u!114 &1159778321
+MonoBehaviour:
+  m_ObjectHideFlags: 0
+  m_CorrespondingSourceObject: {fileID: 0}
+  m_PrefabInternal: {fileID: 0}
+  m_GameObject: {fileID: 1159778316}
+  m_Enabled: 1
+  m_EditorHideFlags: 0
+  m_Script: {fileID: 11500000, guid: f39ae345006ac34439a9940db524a9c9, type: 3}
+  m_Name: 
+  m_EditorClassIdentifier: 
+  btn: {fileID: 1159778318}
+  handler: {fileID: 2108964572}
 --- !u!1 &1165980183
 GameObject:
   m_ObjectHideFlags: 0
@@ -16872,6 +16886,12 @@ MeshFilter:
   m_PrefabInternal: {fileID: 0}
   m_GameObject: {fileID: 2087131127}
   m_Mesh: {fileID: 10202, guid: 0000000000000000e000000000000000, type: 0}
+--- !u!114 &2108964572 stripped
+MonoBehaviour:
+  m_CorrespondingSourceObject: {fileID: 114816571305489748, guid: e0aba74480574f74bb472bbb64f825e7,
+    type: 2}
+  m_PrefabInternal: {fileID: 797608226}
+  m_Script: {fileID: 11500000, guid: 341fd65ce12642e4ca2eaff0dfb9c910, type: 3}
 --- !u!1 &2117357759
 GameObject:
   m_ObjectHideFlags: 0

Assets/UndoButtonHandler.cs

@@ -0,0 +1,25 @@
+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine.UI;
+using UnityEngine;
+
+public class UndoButtonHandler : MonoBehaviour {
+
+    public Button btn;
+    public BallonImageHandler handler;
+
+	// Use this for initialization
+	void Start () {
+        btn.onClick.AddListener(OnClick);
+	}
+
+	// Update is called once per frame
+	void Update () {
+
+	}
+
+    void OnClick()
+    {
+        handler.Undo();
+    }
+}