Animate LayoutParams changes in ConstraintLayout

Question

I am creating app in which there is screen with searchBar by this lib. My activity layout looks like this:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

<android.support.constraint.ConstraintLayout
        android:id="@+id/wrapper"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:animateLayoutChanges="true">

    <TextView
            android:id="@+id/title"
            android:textColor="@color/colorPrimary"
            android:text="@string/mainScreenTitle"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:textAlignment="center"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            android:paddingTop="100dp"/>

    <com.arlib.floatingsearchview.FloatingSearchView
            android:id="@+id/searchView"
            android:layout_width="0dp"
            android:layout_height="50dp"
            android:layout_marginTop="100dp"
            android:animateLayoutChanges="true"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toBottomOf="@+id/title"/>

</android.support.constraint.ConstraintLayout>

</RelativeLayout>

There i have to move FloatingSearchingView to top of screen and change height to for example 500dp - like this:

app:layout_constraintTop_toTopOf="parent"
android:layout_height="500dp"

And later i will have to move it back and change height again to default value

app:layout_constraintTop_toBottomOf="@+id/title"
android:layout_height="50dp"

The problem is, i have to animate it. I have spent a lot of time searching for solution but unfortunately i didnt find anything.

Answer 1

我必须在 ConstraintLayout 内对 TextView 高度进行动画处理。

 <androidx.constraintlayout.widget.ConstraintLayout
                ...
                android:animateLayoutChanges="true"
                >

                <TextView
                 ...

我首先通知 ConstraintLayout 布局即将改变：

constraintlayout.getLayoutTransition().enableTransitionType(LayoutTransition.CHANGING);

然后更新 textView 高度（或任何其他参数）

textView.getLayoutParams().height = 200;
textView.requestLayout();

对于这样简单的事情，不需要设置动画师或涉及其他库。

Answer 2

Animation尝试为此使用类：

Animation animation = new Animation() {

    @Override
    protected void applyTransformation(float interpolatedTime, Transformation t) {
        LayoutParams params = yourView.getLayoutParams();

        // modify your layout params here

        yourView.setLayoutParams(params);
    }
};
animation.setDuration(500); // in ms
yourView.startAnimation(animation);