android按钮动画。如何先获得动画，在活动前单击

<Button
    android:id="@+id/myButton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="点击我"
    />

Button myButton = findViewById(R.id.myButton);
Animation animation = AnimationUtils.loadAnimation(this, R.anim.button_animation);
myButton.startAnimation(animation);

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
    <scale
        android:fromXScale="1.0"
        android:toXScale="1.2"
        android:fromYScale="1.0"
        android:toYScale="1.2"
        android:pivotX="50%"
        android:pivotY="50%"
        android:duration="200"
        android:repeatCount="infinite"
        android:repeatMode="reverse"
        />
</set>