Expand/collapse animation in CardView

Question

I try to do something like this :

I managed to do my cardViewAdapter but I block to enlarge my cards. I resumed the code of this response (Here the name of the cla

Answer 1

You'll need to create a custom class that extends CardView. Inside that class put the following methods:

public void expand() {
    int initialHeight = getHeight();

    measure(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
    int targetHeight = getMeasuredHeight();

    int distanceToExpand = targetHeight - initialHeight;

    Animation a = new Animation() {
        @Override
        protected void applyTransformation(float interpolatedTime, Transformation t) {
            if (interpolatedTime == 1){
                // Do this after expanded
            }

            getLayoutParams().height = (int) (initialHeight + (distanceToExpand * interpolatedTime));
            requestLayout();
        }

        @Override
        public boolean willChangeBounds() {
            return true;
        }
    };

    a.setDuration((long) distanceToExpand);
    startAnimation(a);
}

public void collapse(int collapsedHeight) {
    int initialHeight = getMeasuredHeight();

    int distanceToCollapse = (int) (initialHeight - collapsedHeight);

    Animation a = new Animation() {
        @Override
        protected void applyTransformation(float interpolatedTime, Transformation t) {
            if (interpolatedTime == 1){
                // Do this after collapsed
            }


            Log.i(TAG, "Collapse | InterpolatedTime = " + interpolatedTime);

            getLayoutParams().height = (int) (initialHeight - (distanceToCollapse * interpolatedTime));
            requestLayout();
        }

        @Override
        public boolean willChangeBounds() {
            return true;
        }
    };

    a.setDuration((long) distanceToCollapse);
    startAnimation(a);
}

Note that when you collapse it, you'll need to pass along the height you want it to be when collapsed. The height when expanded is set to WRAP_CONTENT.

I've also added if/else statements that will run when the animation has completed.

Good luck!

Answer 2

I did not understand what you meant by displaying 10 elements out of 50. However, you can achieve the expand/collapse simply by showing/hiding the views and providing android:animateLayoutChanges="true" into the child layout of the CardView. Here is an example:

<android.support.v7.widget.CardView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:animateLayoutChanges="true"
        android:padding="16dp"
        android:orientation="vertical">

        <TextView
            android:id="@+id/hello"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Hello World!"/>

        <TextView
            android:id="@+id/hello2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Hello World!"
            android:visibility="gone"/>

        <TextView
            android:id="@+id/hello3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Hello World!"
            android:visibility="gone"/>

    </LinearLayout>
</android.support.v7.widget.CardView>

And corresponding controller:

    TextView t1 = (TextView) findViewById(R.id.hello);
    final TextView t2 = (TextView) findViewById(R.id.hello2);
    final TextView t3 = (TextView) findViewById(R.id.hello3);

    t1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            if (t2.getVisibility() == View.GONE) {
                t2.setVisibility(View.VISIBLE);
                t3.setVisibility(View.VISIBLE);
            } else {
                t2.setVisibility(View.GONE);
                t3.setVisibility(View.GONE);
            }
        }
    });

Tapping on the first TextView will collapse and expand the CardView along with the animation.