TranslateAnimationEx.java

package com.linkbubble.util;

import android.view.animation.Animation;
import android.view.animation.Transformation;

/**
 * An animation that controls the position and scale of an object. See the
 * {@link android.view.animation full package} description for details and
 * sample code.
 *
 * Extended to added a TransformationListener
 */
public class TranslateAnimationEx extends Animation {
    private int mFromXType = ABSOLUTE;
    private int mToXType = ABSOLUTE;

    private int mFromYType = ABSOLUTE;
    private int mToYType = ABSOLUTE;

    private float mFromXValue = 0.0f;
    private float mToXValue = 0.0f;

    private float mFromYValue = 0.0f;
    private float mToYValue = 0.0f;

    private float mFromXDelta;
    private float mToXDelta;
    private float mFromYDelta;
    private float mToYDelta;

    public interface TransformationListener {
        void onApplyTransform(float interpolatedTime, Transformation t, float dx, float dy);
    }

    TransformationListener mTransformationListener;

    /**
     * Constructor to use when building a TranslateAnimation from code
     * 
     * @param fromXDelta Change in X coordinate to apply at the start of the
     *        animation
     * @param toXDelta Change in X coordinate to apply at the end of the
     *        animation
     * @param fromYDelta Change in Y coordinate to apply at the start of the
     *        animation
     * @param toYDelta Change in Y coordinate to apply at the end of the
     *        animation
     */
    public TranslateAnimationEx(float fromXDelta, float toXDelta, float fromYDelta, float toYDelta, TransformationListener transformationListener) {
        mFromXValue = fromXDelta;
        mToXValue = toXDelta;
        mFromYValue = fromYDelta;
        mToYValue = toYDelta;

        mFromXType = ABSOLUTE;
        mToXType = ABSOLUTE;
        mFromYType = ABSOLUTE;
        mToYType = ABSOLUTE;

        mTransformationListener = transformationListener;
    }

    @Override
    protected void applyTransformation(float interpolatedTime, Transformation t) {
        float dx = mFromXDelta;
        float dy = mFromYDelta;
        if (mFromXDelta != mToXDelta) {
            dx = mFromXDelta + ((mToXDelta - mFromXDelta) * interpolatedTime);
        }
        if (mFromYDelta != mToYDelta) {
            dy = mFromYDelta + ((mToYDelta - mFromYDelta) * interpolatedTime);
        }
        t.getMatrix().setTranslate(dx, dy);

        if (mTransformationListener != null) {
            mTransformationListener.onApplyTransform(interpolatedTime, t, dx, dy);
        }
    }

    @Override
    public void initialize(int width, int height, int parentWidth, int parentHeight) {
        super.initialize(width, height, parentWidth, parentHeight);
        mFromXDelta = resolveSize(mFromXType, mFromXValue, width, parentWidth);
        mToXDelta = resolveSize(mToXType, mToXValue, width, parentWidth);
        mFromYDelta = resolveSize(mFromYType, mFromYValue, height, parentHeight);
        mToYDelta = resolveSize(mToYType, mToYValue, height, parentHeight);
    }
}