Android TextView tween animation doesn't scale properly

Question

I can't seem to figure out this one. I'm working on an android project where I have created a tween animation that scales the TextView a number of times. My animation resource is defined as follows...

<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:interpolator="@android:anim/decelerate_interpolator">

    <scale android:fromXScale="1" android:fromYScale="1"
        android:toXScale="2" android:toYScale="2"
        android:pivotX="50%" android:pivotY="50%"
        android:duration="500"
        android:startOffset="0"/>

    <scale android:fromXScale="2" android:fromYScale="2"
        android:toXScale="1" android:toYScale="1"
        android:pivotX="50%" android:pivotY="50%"
        android:duration="500"
        android:startOffset="500"/>

    <scale android:fromXScale="1" android:fromYScale="1"
        android:toXScale="2" android:toYScale="2"
        android:pivotX="50%" android:pivotY="50%"
        android:duration="500"
        android:startOffset="1000"/>

    <scale android:fromXScale="2" android:fromYScale="2"
        android:toXScale="1" android:toYScale="1"
        android:pivotX="50%" android:pivotY="50%"
        android:duration="500"
        android:startOffset="1500"/>

</set>

The TextView to which the animation is applied is defined in an xml layout resource file inside a RelativeLayout as follows...

<TextView
            android:id="@+id/textView1"
            android:text="@string/textView1Text"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="@color/text_color"
            android:shadowColor="@color/text_shadow_color"
            android:shadowDx="0.0"
            android:shadowDy="0.0"
            android:shadowRadius="20.0"
            android:textSize="@dimen/text_size_large"
            android:layout_centerInParent="true"/>

Then, the animation is initialized and loaded from an activity...

animation1 = AnimationUtils.loadAnimation(this, R.anim.textview_grow_shrink);
textView1.startAnimation(growShrinkAnimation);

I think the code explains the intention which is scaling the TextView from big to small and viceversa

The problem

While the animation does start and runs as intended it seems that scaling is out of proportion while the animation is running. The TextView seems to grow way too big out of the screen boundaries until the animation stops and the TextView goes back to its initial state.

I have no idea if the initial size of the text has anything to do with this weird behaviour. The textSize property is set to 36sp through a value resource (text_size_large) set in the dimens resource file

Question

Has anybody had this problem before? Is it something obvious I'm missing? How can I get this to work as expected?

I've tried Googling using several keywords but the articles that popped up where slightly unrelated. Cheers

Leo Leo · Accepted Answer · 2014-07-12T17:39:13

After some hours of desperation looking for a solution I still don't know what was going wrong and I believe there was a combination of issues I was having:

starting the animation on the activity's onCreate method. Moving this operation to a Handler's postDelayed fixed the scaling issue
I have the feeling the Animations API is buggy as many posts suggested

I resorted to using a single animation rather than using a set based on some article suggesting issues with animation sets...

<scale xmlns:android="http://schemas.android.com/apk/res/android"
    android:interpolator="@android:anim/accelerate_decelerate_interpolator"
    android:fromXScale="1.0"
    android:fromYScale="1.0"
    android:toYScale="0.9"
    android:toXScale="0.9"
    android:pivotX="50%"
    android:pivotY="50%"
    android:repeatCount="infinite"
    android:repeatMode="reverse"
    android:duration="700"
    android:startOffset="0" />

Android TextView tween animation doesn't scale properly

The problem

Question

1 Answers