Button animation: text is animated, but background shape is static

Question

I have a button animation which is defined to scale from 1.0 to 1.1 and back. The text of the button ("Next") scales up and then down, but the button size does not change.
1. Is this expected behavior?
2. There is a jerk when it restarts the animation. I assume this is happening at the loadAnimation() call. Is there a way to make that seamless?

public void startAnimation() {

        final View nextButtonView = fragmentActivity.findViewById(R.id.game2NextButton);
        nextButtonView.setVisibility(View.VISIBLE);

        Animation anim = AnimationUtils.loadAnimation(fragmentActivity, R.anim.scale_button);
        anim.setAnimationListener(new AnimationListener() {

            @Override
            public void onAnimationEnd(Animation arg0) {
                Animation anim = AnimationUtils.loadAnimation(fragmentActivity, R.anim.scale_button);
                anim.setAnimationListener(this);
                nextButtonView.startAnimation(anim);

            }

            @Override
            public void onAnimationRepeat(Animation arg0) {
                // TODO Auto-generated method stub

            }

            @Override
            public void onAnimationStart(Animation arg0) {
                // TODO Auto-generated method stub

            }

        });

        nextButtonView.startAnimation(anim);
    }

scale_button.xml:

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android" >

    <scale
        android:duration="1000"
        android:fillBefore="false"
        android:fillAfter="false"
        android:fromXScale="1.0"
        android:fromYScale="1.0"
        android:interpolator="@android:anim/accelerate_decelerate_interpolator"
        android:pivotX="50%"
        android:pivotY="50%"
        android:toXScale="1.1"
        android:toYScale="1.1" />

    <set android:interpolator="@android:anim/decelerate_interpolator" >
        <scale
            android:duration="1000"
            android:fillBefore="false"
            android:fillAfter="false"
            android:fromXScale="1.1"
            android:fromYScale="1.1"
            android:pivotX="50%"
            android:pivotY="50%"
            android:startOffset="1000"
            android:toXScale="1.0"
            android:toYScale="1.0" />

    </set>

</set>

Next Button is in layout like so:

<LinearLayout
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:layout_weight="1"
    android:gravity="center"
    android:orientation="horizontal" >

    <Button
        android:id="@+id/game2NextButton"
        style="@style/navigation_button"
        android:contentDescription="@string/nextbutton"
        android:text="@string/next" />
</LinearLayout>

Navigation button style:

<style name="navigation_button">
    <item name="android:layout_width">320dp</item>
    <item name="android:layout_height">80dp</item>
    <item name="android:textColor">@drawable/text_color</item>
    <item name="android:background">@drawable/navigation_button_shape</item>
    <item name="android:onClick">onButtonClicked</item>
    <item name="android:textSize">32sp</item>
    <item name="android:textStyle">bold</item>
    <item name="android:maxLines">1</item>
</style>

Button shape:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle" >

    <solid android:color="@color/darkgrey2" />

    <padding
        android:bottom="10dp"
        android:left="10dp"
        android:right="10dp"
        android:top="10dp" />

</shape>

Edit: As Ercan suggests, then best approach is to use android:repeatMode="reverse" as below. Thus the animation is implemented entirely on xml.

<?xml version="1.0" encoding="utf-8"?>
<scale xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="1000"
    android:fillAfter="true"
    android:fillBefore="true"
    android:fromXScale="1.0"
    android:fromYScale="1.0"
    android:interpolator="@android:anim/decelerate_interpolator"
    android:pivotX="50%"
    android:pivotY="50%"
    android:repeatCount="infinite"
    android:repeatMode="reverse"
    android:toXScale="1.1"
    android:toYScale="1.1" />

Answer 1

1. This is an expected behavior. The view animation does not really scale the view bounds. It only scales the image of it. Use ObjectAnimator for this purpose. if you are supporting pre honeycomb i recommd Jake Wharton's 9olddroids library

2.As I see from here, you are trying to repeat the same animation infinitely by restarting.

you may do it by adding :

android:repeatCount="infinite"

and also you can use this to obtain more seamless result :

 android:repeatMode="reverse"

I hope this helps.