MatrixEvaluator.java

package com.cheng.animationstudy.customevaluator;

import android.animation.TypeEvaluator;
import android.graphics.Matrix;

/**
 *
 */
public class MatrixEvaluator implements TypeEvaluator<Matrix> {

    @Override
    public Matrix evaluate(float fraction, Matrix startValue, Matrix endValue) {
        float[] startEntries = new float[9];
        float[] endEntries = new float[9];
        float[] currentEntries = new float[9];

        startValue.getValues(startEntries);
        endValue.getValues(endEntries);

        for (int i = 0; i < 9; i++) {
            currentEntries[i] = (1 - fraction) * startEntries[i] + fraction * endEntries[i];
        }
        Matrix matrix = new Matrix();
        matrix.setValues(currentEntries);

        return matrix;
    }
}