Hello

I was trying to add an animation transition to my character so have written some code:

void Update()
    {
        Vector3 characterScale = transform.localScale;
        if (Input.GetKey(KeyCode.A))
        {
            animator.SetFloat("speed", velocity);
            characterScale.x = 1;
            transform.Translate(Vector2.right * Time.deltaTime * velocity);
        }
        else animator.SetFloat("speed", 0);


        if (Input.GetKey(KeyCode.D))
        {
            animator.SetFloat("speed", velocity);
            characterScale.x = 1;
            transform.Translate(Vector2.right * Time.deltaTime * velocity);
        }
        else animator.SetFloat("speed", 0);
        

        if (Input.GetKeyDown(KeyCode.Space) && Cground == true)
        {
            rb.AddForce(new Vector2(0f, jumpheight), ForceMode2D.Impulse);
            Cground = false;
        }
        transform.localScale = characterScale;
    }

heres my animation controller:

The Problem

My problem is that the speed parameter will only work with the animation transition when walking to the right by pressing D. if i then press A to walk to the left my character sprite flips, he moves but he wont transition to the run animation. I have no idea why and i would be very happy for any help =).

Your problem are the else cases!

Think about what happens if you only press A: Then you are not pressing D.

Which means the last thing you do is

else animator.SetFloat("speed", 0);

so resetting the speed you just had changed for the A press.

You should rather change your checks to e.g.

if (Input.GetKey(KeyCode.A) || Input.GetKey(KeyCode.D))
{
    animator.SetFloat("speed", velocity);
    characterScale.x = 1;
    transform.Translate(Vector2.right * Time.deltaTime * velocity);
}
else 
{
    // Only do this if none of the move keys is pressed
    animator.SetFloat("speed", 0);
}

since apparently anyway you do the se in both cases.

Or actually I thought you would rather move to the other direction when pressing A.

Then I would still do

if (Input.GetKey(KeyCode.A))
{
    animator.SetFloat("speed", velocity);
    characterScale.x = 1;
    transform.Translate(Vector2.left * Time.deltaTime * velocity);
}
else if (Input.GetKey(KeyCode.A))
{
    animator.SetFloat("speed", velocity);
    characterScale.x = 1;
    transform.Translate(Vector2.right * Time.deltaTime * velocity);
}
else 
{
    animator.SetFloat("speed", 0);
}