Object.DontDestroyOnLoad

パラメーター

説明

Do not destroy the target Object when loading a new Scene.

The load of a new Scene destroys all current Scene objects. Call Object.DontDestroyOnLoad to preserve an Object during scene loading. If the target Object is a component or GameObject, Unity also preserves all of the Transform’s children. Object.DontDestroyOnLoad only works for root GameObjects or components on root GameObjects. Object.DontDestroyOnLoad does not return a value.

The following example script uses Object.DontDestroyOnLoad. The example has scene1 which starts playing background music from an AudioSource. The music continues when scene2 loads. Switch between scenes using a button.

To implement this example, create two new Scenes, named scene1 and scene2. Open scene1 and add the SceneSwap.cs script to an empty GameObject and name it Menu. Next, add DontDestroy.cs to a new GameObject and name it BackgroundMusic. Add an AudioSource to BackgroundMusic - Add Component > Audio > Audio Source - and import an AudioClip into your Project. Assign the AudioClip to the AudioSource’s AudioClip field. Create a tag, call it music, and add it to BackgroundMusic. Switch to scene2. Again add SceneSwap.cs to a new GameObject and name it Menu. Save the Project. Return to scene1 and run the Project from the Editor.

SceneSwap.cs script:

using UnityEngine;
using UnityEngine.SceneManagement;

// Object.DontDestroyOnLoad example.
//
// Two scenes call each other. This happens when OnGUI button is clicked.
// scene1 will load scene2; scene2 will load scene1. Both scenes have
// the Menu GameObject with the SceneSwap.cs script attached.
//
// AudioSource plays an AudioClip as the game runs. This is on the
// BackgroundMusic GameObject which has a music tag.  The audio
// starts in AudioSource.playOnAwake. The DontDestroy.cs script
// is attached to BackgroundMusic.

public class SceneSwap : MonoBehaviour
{
    private void OnGUI()
    {
        int xCenter = (Screen.width / 2);
        int yCenter = (Screen.height / 2);
        int width = 400;
        int height = 120;

        GUIStyle fontSize = new GUIStyle(GUI.skin.GetStyle("button"));
        fontSize.fontSize = 32;

        Scene scene = SceneManager.GetActiveScene();

        if (scene.name == "scene1")
        {
            // Show a button to allow scene2 to be switched to.
            if (GUI.Button(new Rect(xCenter - width / 2, yCenter - height / 2, width, height), "Load second scene", fontSize))
            {
                SceneManager.LoadScene("scene2");
            }
        }
        else
        {
            // Show a button to allow scene1 to be returned to.
            if (GUI.Button(new Rect(xCenter - width / 2, yCenter - height / 2, width, height), "Return to first scene", fontSize))
            {
                SceneManager.LoadScene("scene1");
            }
        }
    }
}

DontDestroy.cs script:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

// Object.DontDestroyOnLoad example.
//
// This script example manages the playing audio. The GameObject with the
// "music" tag is the BackgroundMusic GameObject. The AudioSource has the
// audio attached to the AudioClip.

public class DontDestroy : MonoBehaviour
{
    void Awake()
    {
        GameObject[] objs = GameObject.FindGameObjectsWithTag("music");

        if (objs.Length > 1)
        {
            Destroy(this.gameObject);
        }

        DontDestroyOnLoad(this.gameObject);
    }
}