How to play an AnimationClip when key is pressed in Unity3d, C#?

Question

1. I have tried this code, but it doesn't work.

2. Can someone help me, and can someone explain things about animations in Unity 3D? I have tried so much, google, youtube etc.

   using UnityEngine;
   using System.Collections;
   
   public class PlayAnimation : MonoBehaviour {
   
       public AnimationClip walk;
       Animation anim;
   
       void Update () {
           if (Input.GetKeyDown(KeyCode.W)){
               anim.clip = walk;
               anim.Play();        
           }
       }
   }
   

Solution 1

By the looks of your code you're never actually referencing the attached Animaton on your component. Try assigning anim it's component in the Start method, like this:

public class PlayAnimation : MonoBehaviour 
{

    public AnimationClip walk;
    Animation anim;
 
    void Start() 
    {
        anim = GetComponent<Animation>();
    }
     
    void Update () 
    {
        if (Input.GetKeyDown(KeyCode.W)) 
        {
            anim.clip = walk;
            anim.Play();        
        }
    }
}

Solution 2

The anim variable is not initialized. You can initialize it in two ways:

1.GetComponent

If the Animation component is attached to the-same Gameobject your PlayAnimation script is attached to:

void Start()
{
    anim = GetComponent<Animation>();
}

If the Animation component is attached to different Gameobject:

void Start()
{
    anim = GameObject.Find("GameObjectAnimationIsAttachedTo").GetComponent<Animation>();
}

2.Make anim variable public then assign it from the Editor.

Animation anim; should be public Animation anim;. Now, drag the GameObject with the Animation component to the anim variable.

Solution 3

This is my code now and it works, thanks to Frederik. I got now how the parameters work and the animator.

 using UnityEngine;
 using System.Collections;

public class PlayAnimation : MonoBehaviour {
public Animator animator;
byte idle=0;
byte walk=1;
byte sprint=2;

// Use this for initialization
void Start () {
    animator = GetComponent<Animator> ();
}

// Update is called once per frame
void Update () {
    if (Input.GetKey (KeyCode.W)) {
        animator.SetInteger ("Anumber", walk);
    } else if (Input.GetKey (KeyCode.A)) {
        animator.SetInteger ("Anumber", walk);
    } else if (Input.GetKey (KeyCode.S)) {
        animator.SetInteger ("Anumber", walk);
    } else if (Input.GetKey (KeyCode.D)) {
        animator.SetInteger ("Anumber", walk);
    } else {
        animator.SetInteger ("Anumber", idle);
    }
}
    }

Comments

[Fredrik Schön]

Photo finish on that one, but you beat me to it! Ha!

[Programmer]

Lol I know. I was typing when I saw your comment so I knew you were going to post. Anyways, +1.

[Je moder]

Thanks for your reply, I have changed it in my script, but it doesn't work. I've got a 3d model with an animator, animation and my script in the inspector. But if I enable the animator, the animation plays all the time and if I release the W button too. If I disable him, there plays nothing.

[Fredrik Schön]

May I suggest you check a quick tutorial on Animator, Animatons and how to control them? It's only 8 minutes: youtube.com/watch?v=JeZkctmoBPw and if you've got a somewhat grasp on it you can always watch it on higher speed! How I usually do things is to set up a pattern in the animator, then add variables to the transitions between animation, then control those variables with animator.setBool("Walk", true); for instance, thus telling the animator to animate the Walking animation

[Je moder]

Okay, I will check it.

[Je moder]

And sorry for my bad English by the way, I am from the Netherlands.

[Fredrik Schön]

niet een probleem. sorry voor bad nederlands!

[Je moder]

I have seen the video, but I don't understand why parameters are useful. Can you explain me that better than the video.

[Fredrik Schön]

Oh, ummm... Let's imagine we have a game where the player has 3 animations: Idle, Walk & Run. You can set a parameter float "movementspeed" which will be updated with the speed of the player every Update. In our animator we have Idle -> Walk -> Run where the -> represent a transition based on the movementspeed parameter. When Movementspeed is 0 we show idle, when it's 0><4 we show walk and when it's >5 we transition to Run. You can also control specific transitions between animation when you do it like this, for instance maybe the transition from Walk -> Run should start 50% in on Walk.

[Fredrik Schön]

By using parameters we get a dynamic lifecycle of animations. Animation.Play(); (I've never used it but I'm guessing:) just starts the animation on loop? Perhaps not a good example, I don't know. It's the only way I know of doing it, haha.

[Je moder]

How can I do that, that a parameter changes when the speed changes of my character?

[Fredrik Schön]

Assuming you have a 2D game and an animator set up with a float parameter called "Movementspeed": in your Update() method you do animator.SetFloat("Movementspeed", rigidbody.velocity.x); where animator is an Animator (animator = GetComponent<Animator>();) and rigidbody.velocity.x is the speed of the rigidbody in x-axis.

[Fredrik Schön]

But the key element here is to do animator.SetFloat("ParamterName", value); every frame so your animator knows the speed of every frame and can choose which animation to play based on the transition conditions.

[Je moder]

I did it, thanks for help. Great and in the Netherlands we say: Top!

[Alox]

@DaniëlvanderZwan Did this answer solve your question? If it did, be sure to accept it.

[Fredrik Schön]

It seems @DaniëlvanderZwan replied with an answer that shows how he solved it, which is great! You should Accept that answer as the answer for people who needs similar help!