Unity：无法找到所有带有标签的对象

Question

I'm working on a TD game, and there's an option to change volume during gameplay. It worked fine when I first wrote it, but now it doesn't, and I'm pretty sure no one changed the relevant parts.

There are several components that I'm using.

First, there's a small script attached to the turrets that sets the AudioSource volume to the value set in PlayerPrefs . It's pretty straightforward.

void Start () {
    SetVolume();
}

public void SetVolume() {
    if (gameObject.GetComponent<AudioSource> () == null) {
        gameObject.AddComponent<AudioSource> ();
    }
    gameObject.GetComponent<AudioSource>().volume = PlayerPrefs.GetFloat ("SFXVolume");
}

Then there's the script that's called from the volume settings. When the user slides the volume slider, the value is saved in PlayerPrefs , then I search for objects with the Turret tag and change their volume in a loop.

void Start () {
    musSlider = GameObject.Find ("MusicSlider");
    sfxSlider = GameObject.Find ("SFXSlider");
    if (!(PlayerPrefs.HasKey ("MusicVolume"))) {
        PlayerPrefs.SetFloat ("MusicVolume", 1.0f);
        PlayerPrefs.SetFloat ("SFXVolume", 1.0f);
    }
    musSlider.GetComponent <Slider> ().value = PlayerPrefs.GetFloat ("MusicVolume");
    sfxSlider.GetComponent <Slider> ().value = PlayerPrefs.GetFloat ("SFXVolume");
}

public void SetSFXVolume() {
    PlayerPrefs.SetFloat ("SFXVolume", sfxSlider.GetComponent <Slider> ().normalizedValue);
    if (!(String.Equals (SceneManager.GetActiveScene ().name, "VietrixMainMenuScene"))) {
        GameObject[] turrets = GameObject.FindGameObjectsWithTag("Turret");
        for (int i = 0; i < turrets.Length; i++) {
            if (String.Equals (turrets [i].name, "Turret")) {
                Debug.Log ("Turret name: " + turrets [i].transform.parent.gameObject.name);
            } else {
                Debug.Log ("Turret name: " + turrets [i].name);
            }
            turrets[i].GetComponent<AudioSource> ().volume = PlayerPrefs.GetFloat ("SFXVolume");
        }
    }
}

And here the things go wrong. I currently have 6 Turrets in the scene, and only 4 of them show up in the log, and their volume changes. All of the tags are in place, I've just checked it for the umpteenth time. Out of the 4 that show up, 3 have tags on the turrets themselves, and 1 has tags on both the turret and its parent object. Out of the 2 that don't show up, 1 has the tag on the turret itself, and the other has tags on both the turret and the parent object.

What could have happened? I'm not the only one working on this game, but the others swear they haven't touched the tags or the volume scripts.

Answer 1

Instead of manually changing the volume of each audio source, it is probably better to look into the AudioMixer which already does what you are trying to do. Here's a tutorial on it.

Using the names of GameObjects to try and find the right one isn't a great idea, since names can change (eg when they are instantiated, they will be Turret (Clone)).

If you're really set on your solution, why not just do this in your VolumeSettings script in SetSFXVolume (assuming that the small script on your turrets is named AudioSourceBuddy):

public void SetSFXVolume() {
    PlayerPrefs.SetFloat ("SFXVolume", sfxSlider.GetComponent <Slider> ().normalizedValue);
    if (!(String.Equals (SceneManager.GetActiveScene ().name, "VietrixMainMenuScene"))) {
        foreach(AudioSourceBuddy buddy in GameObject.FindObjectsOfType<AudioSourceBuddy >()) { 
            buddy.SetVolume();
        }
    }
}

That way you don't have to worry about looping through tags, checking names, etc. You can just find all of the sources directly.