Resizing layouts programmatically (as animation)

Question

I want to resize some layouts in my Activity.

Here is the code of the main XML:

<LinearLayout
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_weight="1"
    android:orientation="vertical" >

    <LinearLayout
        android:id="@+id/top"
        android:layout_width="fill_parent"
        android:layout_height="0dip"
        android:layout_weight="1"
        android:background="#3ee3e3" >
    </LinearLayout>

    <LinearLayout
        android:id="@+id/middle"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_weight="1">
    </LinearLayout>

    <LinearLayout
        android:id="@+id/bottom"
        android:layout_width="fill_parent"
        android:layout_height="0dip"
        android:layout_weight="1"
        android:background="#fe51e6" >
    </LinearLayout>
</LinearLayout>

As you can see, the top and bottom layouts height's is 0, and the middle layout covers all the place.

I want to programmatically decrease the middle layout size, while increase both the top and the bottom layout sizes, till all the layouts have the same height.

I want it to be look like an animation.

How should I do that?

Thanks

Answer 1

I wrote a ResizeAnimation for a similar purpose. It's simple but costly.

Java

    /**
     * an animation for resizing the view.
     */
    public class ResizeAnimation extends Animation {
        private View mView;
        private float mToHeight;
        private float mFromHeight;

        private float mToWidth;
        private float mFromWidth;

        public ResizeAnimation(View v, float fromWidth, float fromHeight, float toWidth, float toHeight) {
            mToHeight = toHeight;
            mToWidth = toWidth;
            mFromHeight = fromHeight;
            mFromWidth = fromWidth;
            mView = v;
            setDuration(300);
        }

        @Override
        protected void applyTransformation(float interpolatedTime, Transformation t) {
            float height =
                    (mToHeight - mFromHeight) * interpolatedTime + mFromHeight;
            float width = (mToWidth - mFromWidth) * interpolatedTime + mFromWidth;
            LayoutParams p = mView.getLayoutParams();
            p.height = (int) height;
            p.width = (int) width;
            mView.requestLayout();
        }
    }

Kotlin

class ResizeAnimation(
    private val view: View,
    private val toHeight: Float,
    private val fromHeight: Float,
    private val toWidth: Float,
    private val fromWidth: Float,
    duration: Long
) : Animation() {

    init {
        this.duration = duration
    }

    override fun applyTransformation(
        interpolatedTime: Float,
        t: Transformation?
    ) {
        val height = (toHeight - fromHeight) * interpolatedTime + fromHeight
        val width = (toWidth - fromWidth) * interpolatedTime + fromWidth
        val layoutParams = view.layoutParams
        layoutParams.height = height.toInt()
        layoutParams.width = width.toInt()
        view.requestLayout()
    }
}