1.添加矢量图
我们还需要将path 包裹在group 中,因为group 是矢量资源中将被动画化的部分。您可以为组设置任何名称。
res/drawable/ic_arrow_down.xml
<?xml version="1.0" encoding="utf-8"?>
<vector xmlns:android="http://schemas.android.com/apk/res/android"
android:viewportWidth="306"
android:viewportHeight="306"
android:width="306dp"
android:height="306dp">
<group
android:name="arrow"
android:pivotX="153"
android:pivotY="153">
<path
android:pathData="M153 247.35L306 94.35 270.3 58.65 153 175.95 35.7 58.65 0 94.35Z"
android:fillColor="#000000" />
</group>
</vector>
res/drawable/ic_arrow_top.xml
<?xml version="1.0" encoding="utf-8"?>
<vector xmlns:android="http://schemas.android.com/apk/res/android"
android:viewportWidth="306"
android:viewportHeight="306"
android:width="306dp"
android:height="306dp">
<group
android:name="arrow"
android:pivotX="153"
android:pivotY="153">
<path
android:pathData="M270.3 247.35L306 211.65 153 58.65 0 211.65 35.7 247.35 153 130.05Z"
android:fillColor="#000000" />
</group>
</vector>
2。添加动画师
res/animator/animation_arrow_rotation.xml
<?xml version="1.0" encoding="utf-8"?>
<objectAnimator xmlns:android="http://schemas.android.com/apk/res/android"
android:duration="@android:integer/config_shortAnimTime"
android:propertyName="rotation"
android:valueFrom="0"
android:valueTo="180" />
3.添加动画矢量绘图
<target> 引用 group 的名称。
res/drawable/ic_animated_arrow_down.xml
<?xml version="1.0" encoding="utf-8"?>
<animated-vector xmlns:android="http://schemas.android.com/apk/res/android"
android:drawable="@drawable/ic_arrow_down">
<target
android:name="arrow"
android:animation="@animator/animation_arrow_rotation" />
</animated-vector>
res/drawable/ic_animated_arrow_up.xml
<?xml version="1.0" encoding="utf-8"?>
<animated-vector xmlns:android="http://schemas.android.com/apk/res/android"
android:drawable="@drawable/ic_arrow_up">
<target
android:name="arrow"
android:animation="@animator/animation_arrow_rotation" />
</animated-vector>
4.向适配器添加一些代码
在ParentViewHolder的继承者中初始化ImageView:
void bind(UiModel uiModel) {
arrowImageView.setImageResource(isExpanded() ? R.drawable.ic_animated_arrow_down :
R.drawable.ic_animated_arrow_up);
// some other code
}
并覆盖onExpansionToggled:
@Override
public void onExpansionToggled(boolean expanded) {
super.onExpansionToggled(expanded);
arrowImageView.setImageResource(expanded ? R.drawable.ic_animated_arrow_down :
R.drawable.ic_animated_arrow_up);
AnimatedVectorDrawableCompat drawable = (AnimatedVectorDrawableCompat) arrowImageView.getDrawable();
drawable.registerAnimationCallback(new Animatable2Compat.AnimationCallback() {
@Override
public void onAnimationEnd(Drawable ignored) {
drawable.clearAnimationCallbacks();
arrowImageView.setImageResource(expanded ? R.drawable.ic_animated_arrow_up :
R.drawable.ic_animated_arrow_down);
}
});
drawable.start();
}
顺便说一句,您可以在一个 XML 文件中定义 AnimatedVectorDrawable XML 资源。详情here。