How to animate an adding of a view in Android?

I would like to know if there is a simple way to add a view (a button) to a RelativeLayout, with some kind of scale animation. I extended a clas开发者_如何学Pythons from Button and did something like this:

    public class MyButton extends Button {

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();
        ScaleAnimation anim = new ScaleAnimation(0,1,0,1);
        anim.setDuration(1000);
        anim.setFillAfter(true);
        this.startAnimation(anim);
    }

Then tried to add this button to a view and it didn't work. Please help!

---

In your activity, use instead:

parentview.addView(myButton);

Then animate the button with this:

Animation animation = AnimationUtils.loadAnimation(getBaseContext(), R.anim.slide_right_in);
animation.setStartOffset(0);
myButton.startAnimation(animation);

This is an example of slide_right_in.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <translate android:fromXDelta="100%p" android:toXDelta="0" android:duration="800"/>
</set>

In addition, This is a activity play animation function I wrote:

public Animation PlayAnim( int viewid, Context Con, int animationid, int StartOffset )
{
    View v = findViewById(viewid);

    if( v != null )
    {
        Animation animation = AnimationUtils.loadAnimation(Con, animationid  );
        animation.setStartOffset(StartOffset);
        v.startAnimation(animation);

        return animation;
    }
    return null;
}

You can call this like this:

PlayAnim(R.id.bottombar, (Context) this, R.anim.slide_right_in, 0);

Where:

1st parameter is the id of the view you want to apply the animation on.

2nd paramenter isThe context retrieved inside your activity.

3rd parameter is the desired animation that you put inside your anim resource folder or from android predefined animations.

4rd paremeter is the animation startoffset.

---

I tested your animated button implementation and it works correctly. There must be some other problem. Probably the way you add the button to the layout.

To add your button to the relative layout use code like this.

RelativeLayout rl = (RelativeLayout)findViewById(R.id.rl);
MyButton b1 = new MyButton(Main.this);
b1.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.WRAP_CONTENT));
rl.addView(b1);

Or you can inflate the button from layout. To do this create layout mybtn.xml containing your button implementation:

<?xml version="1.0" encoding="utf-8"?>
<PACKAGE_OF_MYBUTTON_HERE.MyButton
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  />

To add it to your layout call:

RelativeLayout rl = (RelativeLayout)findViewById(R.id.rl);
Button b = (Button)getLayoutInflater().inflate(R.layout.mybtn, rl, false);
rl.addView(b);

There might be a problem with proper positioning of your view when you add it to the relative layout. Just add code like this before calling rl.addView(b1) (the code snippet adds new button below someOtherView).

LayoutParams lp = new LayoutParams(b.getLayoutParams());
lp.addRule(RelativeLayout.BELOW, someOtherView.getId());
b.setLayoutParams(lp);

---

You can try adding this to your code just before adding view.I guess this code would work for any view changes. In my case was switching 2 views with animation.

TransitionManager.beginDelayedTransition(layoutlocation);//layoutlocation is parent layout(In my case relative layout) of the view which you gonna add.

Hope it works.Took 2 days for me to make this work.

---

It's not always necessary to use animation class to get actual animation. We can provide a delay when adding views to layout using handler as shown.

Handler handler = new Handler();
handler.postDelayed(new Runnable() {
    public void run() {
        Animation fadeanimation = new AlphaAnimation(0,1);
        fadeanimation.setDuration(position*60+100);
        child.setAnimation(fadeanimation);
        linearLayout.addView(child);
    }
}, position*60);