Unity Move sprite from point A to point B

Question

Pretty new to Unity and i'm trying to make a very simple iphone game. , I'd like to know how to move a sprite (2D) move from random point A to random Point B not just that, but i want it to change direction halfway through.

here is my attempt:

public float speed;
public float minForce;
public float maxForce;
public float counter;
private float counter2;

void Start () 
{
    Push ();

}

void Update ()
{
    counter2 -= Time.deltaTime;
    if ( counter2 < 0)
    {
        Push ();
        counter2 = counter;

    }

}


void Push ()
{
    float force = Random.Range(minForce, maxForce);
    float x = Random.Range(-1f, 1f);
    float y = Random.Range(-1f, 1f);

    rigidbody2D.AddForce( force * new Vector2(x, y) * speed);
}

}

I'm not quit satisfied with using force, also tried Vector2.lerp but for some reason it just teleported instead of smoothing. Also i want to make it randomly change position only once.

here is my perp attempt:

 private Vector2 startPoint ;


public float speed ;
public float counter;
private float counter2;

void Start () 
{
    startPoint = transform.position;
}

// Update is called once per frame
void Update () 
{
    counter2 -= Time.deltaTime;
    if ( counter2 < 0)
    {
        RandomPosition ();
        counter2 = counter;

    }

}

void RandomPosition ()
{
    float counter = speed * Time.deltaTime;
    float x = Random.Range(-50f, 50f);
    float y = Random.Range(-100f, 100f);
    Vector2 endPoint = new Vector2(x, y);
    transform.position = Vector2.Lerp(transform.position, endPoint,       Time.deltaTime * speed);  
}
}

Answer 1

So, first: If you want to use Vector2.Lerp, you have to call it every frame(Update), with a parameter between 0 and 1 - what you did, is create a new line, Lerp to some random point on it, and discard everything on the next frame.
You also used a lot of local variables for stuff that needs to be class members, because other functions need access to them.

A simple way to do what you want would be

float timer;
Vector3 startPos;
Vector3 endPos;

void Start() 
{
   RandomPosition();
}

void RandomPosition()
{
  timer = Time.time;
  startPos = transform.position;
  endPos = new Vector3(Random.Range(-50f, 50f), Random.Range(-100f, 100f), 0);
}

void Update()
{
  if (Time.time - timer > 1)
  {
    RandomPosition();
  }
  transform.position = Vector3.Lerp(startPos, endPos, Time.time - timer);
}

This is if course quite trivial, p.e. it moves the transform from a to b in one second, without caring about speed, but should get you on the right direction.

Also, if you want to just change direction half way to a new random direction - is that not the same as simply moving only half the way, and then starting again? No need to make it any more complicated.