Unity 游戏对象可见性 - 无法多次显示游戏对象

Question

I have a Canvas with an Image and a TextMeshPro (TMP) as a child, and the dialog's canvas component is set to false in the Start() method so as to hide it in the main Canvas. The TMP appears over the image (like a text inside a dialog box). I have a player and a coin sprite in a 2D environment. When the player picks up the coin, I try to display the dialog box and the TMP as shown below.

public class PlayerMovement : MonoBehaviour {

    public GameObject suggestion;
    public GameObject dialogBox;

    private bool wasSuggestionShown; //to check if dialog was shown

    private void Start()
    {
        wasSuggestionShown = false;
        suggestionTimer = 0;
        dialogBox.GetComponent<Canvas>().enabled = false; //To hide the dialog box
    }

    void Update () {

        //horizontalMove = Input.GetAxisRaw("Horizontal") * runSpeed; // for pc keys
        horizontalMove = CrossPlatformInputManager.GetAxis("Horizontal") * runSpeed; //for smartphone input

        if (wasSuggestionShown)
        {
            suggestionTimer += Time.deltaTime;
            if (suggestionTimer > 5)
            {
                wasSuggestionShown = false;
                dialogBox.GetComponent<Canvas>().enabled = false; //TO hide dialog box after displaying it
            }
        }
    }

    void FixedUpdate ()
    {
        // Move the character
        controller.Move(horizontalMove * Time.fixedDeltaTime, crouch, jump);
        jump = false;
    }


    //For destroying coin object on collision with player
    private void OnTriggerEnter2D(Collider2D col)
    {
        
        if (col.gameObject.CompareTag("coin"))
        {

            //For destroying coin and to recude player movement speed.

            Destroy(col.gameObject); //Coin Disappears

            isRunSpeedReduced = true;
            runSpeed = 10f;

            //For Showing dialog box

            dialogBox.GetComponent<Canvas>().enabled = true;
            wasSuggestionShown = true;
        }
    }
}

In the OnTriggerEnter2D() method, I check if the player character touches the coin and if so, I destroy the object and display the dialog box and TMP and hide them after 5 seconds. The problem is that

"When I include another coin, the same dialog box and TMP, do not show up when the player picks the second coin. Both the coins have the same tag 'coin' "

One may argue that if the script is in the same object which was destroyed or is inactive, then it is impossible. But I am doing all of this in the Player's movement script which is attached to the player Object.

Also, the way that I toggle the dialog box does not make a difference. Be it dialogBox.GetComponent<Canvas>().enabled = true; or dialogBox.SetActive(true) Either of these display only once and that is the first occurence.

Even if I want to instantiate it, I don't know the exact transforms to position it properly in the canvas. (I want it in the bottom middle part, like how it can be anchored)

Scene Hierarchy:

Answer 1

The issue is in your Update() , where you turn off the canvas after suggestionTimer ticks over:

void Update () {

    //horizontalMove = Input.GetAxisRaw("Horizontal") * runSpeed; // for pc keys
    horizontalMove = CrossPlatformInputManager.GetAxis("Horizontal") * runSpeed; //for smartphone input

    if (wasSuggestionShown)
    {
        suggestionTimer += Time.deltaTime;
        if (suggestionTimer > 5)
        {
            wasSuggestionShown = false;
            dialogBox.GetComponent<Canvas>().enabled = false; //TO hide dialog box after displaying it
        }
    }
}

The cause is that you never reset the suggestionTimer when you hit a new coin. Do this:

private void OnTriggerEnter2D(Collider2D col)
{
    
    if (col.gameObject.CompareTag("coin"))
    {

        //For destroying coin and to recude player movement speed.

        Destroy(col.gameObject); //Coin Disappears

        isRunSpeedReduced = true;
        runSpeed = 10f;

        //For Showing dialog box

        dialogBox.GetComponent<Canvas>().enabled = true;
        wasSuggestionShown = true;

        //  !!! ADD THIS
        suggestionTimer = 0;
    }
}

Answer 2

The problem is that on OnTriggerEnter2D , you set wasSuggestionShown = true , and then in the very next Update method, you're checking wasSuggestionShown , seeing that it's true, and turning the canvas off again straight away.

This might help. It's just one, of a dozen ways, that could help:

private bool _showSuggestion = true;
public bool showSuggestion
{
  get { return _showSuggestion; }
  set   
  {
    if ( !value && _showSuggestion )
    {
      dialogBox.SetActive ( false );
      _showSuggestion = value;
    }
  }
}


void Update () {

    //horizontalMove = Input.GetAxisRaw("Horizontal") * runSpeed; // for pc keys
    horizontalMove = CrossPlatformInputManager.GetAxis("Horizontal") * runSpeed; //for smartphone input

    if ( showSuggestion )
    {
        suggestionTimer += Time.deltaTime;
        if ( suggestionTimer > 5f ) showSuggestion = false;
    }
}

The code above will wait until the first time you set showSuggestion to false, and then after that, ignore any further attempt to turn the suggestions on. Which I suspect that's what you'd like? If I'm reading the situation wrong, the code can be jiggled a little to get the right behaviour.