为什么Random.Range与Unity中列表中的按钮位置重叠？

Question

I have a list of UI Buttons and Vector2 for positions. I am using random.range to place buttons randomly every time i load them. But it never shows all 5 buttons at different positions. instead overlapping some of them. Can anyone please help me with this?

[SerializeField] List<Button> answersButtons = new List<Button>();
[SerializeField] List<Vector2> positions = new List<Vector2>();

void ShuffleAnswersList()
{             

    for (int i = 0; i < answersButtons.Count; i++)
    {              
       Vector2 tempPosition = 
       answersButtons[i].GetComponent<RectTransform>().position;

       int randomIndex = Random.Range(0, positions.Count);

       answersButtons[i].transform.position = positions[randomIndex];
       answersButtons[randomIndex].GetComponent<RectTransform>().position 
       = tempPosition;

       Debug.Log(randomIndex);          
    }      

}

// shuffle positions
public void Shuffle()
{
    for (int i = 0; i < positions.Count; i++)
    {
        int rnd = Random.Range(0, positions.Count);
        Vector2 tempGO = positions[rnd];
        positions[rnd] = positions[i];
        positions[i] = tempGO;
    }
}

Answer 1

Try this code, not sure where your Random.Range() function comes from, but there is a built-in Random in System that you can use to get random integers. In this example the random is declared ahead and the Next() function is used to get a random number:

void Shuffle()
{
    System.Random random = new System.Random();
    for (int i = 0; i < positions.Count; i++)
    {
        int rnd = random.Next(0, positions.Count);
        Vector2 tempGO = positions[rnd];
        positions[rnd] = positions[i];
        positions[i] = tempGO;
    }
}

Answer 2

When you are doing this :

int randomIndex = Random.Range(0, positions.Count);

answersButtons[i].transform.position = positions[randomIndex];

You may get the same value when you are randoming, that's why some button are overlapping.

You want to either :

• Shuffle the list of the position (what you did) and keep the same order for answers list

• Shuffle the list of answers and keep the same order for position

Try this instead :

void ShuffleAnswersList()
{             
    //  Notice this v--------------------v to avoid out of range exception
    for (int i = 0; i < positions.Count && i < answersButtons.Count; i++)
    {
// always use i ------V---------------------------------V
       answersButtons[i].transform.position = positions[i];
    }
}

Of course, make sure you call your method Shuffle first. This method need to be fixed, Random.Range(min, max) may return max (and provide a out of range exception)

// shuffle positions
public void Shuffle()
{
    for (int i = 0; i < positions.Count; i++)
    {
// notice this -------------------------------------V
        int rnd = Random.Range(0, positions.Count - 1);
        Vector2 tempGO = positions[rnd];
        positions[rnd] = positions[i];
        positions[i] = tempGO;
    }
}