在 Compound Drawables Android 上缩放动画

Question

我有一个RadioButton，其drawableTop 设置为LayerList。 LayerList 看起来像这样

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item>
        <shape android:shape="rectangle">
            <solid android:color="@color/image_radio_button_bg_selector" />
            <size
                android:width="@dimen/imageRadioButtonDrawableSize"
                android:height="@dimen/imageRadioButtonDrawableSize" />
            <corners android:radius="@dimen/imageRadioButtonDrawableRadius" />
        </shape>
    </item>
<layer-list>

我希望能够在选中或取消选中RadioButton 时为这个drawable 设置动画。当 RadioButton 被选中时，Drawable 需要从 50% 缩放到 100%，反之亦然。有没有办法在复合绘图中添加动画？特别是当 drawable 由 Color Selector 而不是 Drawable Selector 驱动时。 （在我的情况下为image_radio_button_bg_selector）

那个颜色选择器看起来像这样

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:color="?attr/colorAccent" android:state_checked="true" />
    <item android:color="@android:color/white" android:state_checked="false" />
    <item android:color="@color/white" />
</selector>

Answer 1

在 res/anim/scale.xml 中创建一个文件

<set xmlns:android="http://schemas.android.com/apk/res/android">

    <scale
        android:pivotX="50%"     // anchor point in x-axis->
        android:pivotY="50%"     // anchor point in x-axis
        android:fromYScale="0.5" // from size Y axis
        android:fromXScale="0.5" // from size X axis
        android:interpolator="@android:anim/bounce_interpolator"
        android:toYScale="1.0"   // to size Y axis
        android:toXScale="1.0"   // to size X axis
        android:duration="250"/> // time of duration in milliseconds

</set>

在activity文件中的使用

RadioGroup rGroup = (RadioGroup)findViewById(R.id.radioGroup);
RadioButton checkedRadioButton =(RadioButton)rGroup.findViewById(rGroup.getCheckedRadioButtonId());
rGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
    public void onCheckedChanged(RadioGroup group, int checkedId) {
       RadioButton checkedRadioButton = (RadioButton)group.findViewById(checkedId);
       Animation bulge = AnimationUtils.loadAnimation(getApplication(), R.anim.scale);
                        checkedRadioButton.startAnimation(bulge);
    }
});