Java 类com.nineoldandroids.animation.IntEvaluator 实例源码

private void performAnimate(final View target, final int start, final int end) {
    ValueAnimator valueAnimator = ValueAnimator.ofInt(1, 100);
    valueAnimator.addUpdateListener(new AnimatorUpdateListener() {

        // 持有一个IntEvaluator对象，方便下面估值的时候使用
        private IntEvaluator mEvaluator = new IntEvaluator();

        @Override
        public void onAnimationUpdate(ValueAnimator animator) {
            // 获得当前动画的进度值，整型，1-100之间
            int currentValue = (Integer) animator.getAnimatedValue();
            Log.d(TAG, "current value: " + currentValue);

            // 获得当前进度占整个动画过程的比例，浮点型，0-1之间
            float fraction = animator.getAnimatedFraction();
            // 直接调用整型估值器通过比例计算出宽度，然后再设给Button
            target.getLayoutParams().width = mEvaluator.evaluate(fraction, start, end);
            target.requestLayout();
        }
    });

    valueAnimator.setDuration(5000).start();
}

@Override
protected void resetHeader() {
    final ViewGroup.MarginLayoutParams params = (ViewGroup.MarginLayoutParams) mAnimationView.getLayoutParams();
    ValueAnimator animator = ValueAnimator.ofInt(params.topMargin,(int) - getAnimationEndHeight());

    animator.setEvaluator(new IntEvaluator() {

        @Override
        public Integer evaluate(float fraction, Integer startValue, Integer endValue) {
            int num = (Integer)super.evaluate(fraction, startValue, endValue);
            params.setMargins(0,num, 0, 0);
            mAnimationView.setLayoutParams(params);
            return num;
        }
    });
    animator.setDuration(200);
    animator.start();
}

@Override
protected void buildAnimator() {
    ObjectAnimator animator = (ObjectAnimator) getAnimator();
    if (animator == null) {
        if (mPropertyType == PropertyDataType.UNKNOWN) {
            Log.w(TAG, "Property data type unknown, cannot animate.");
            return;
        }

        Object target = getTarget();
        String propertyName = AnimationUtils.translatePropertyName(target,
                mPropertyName);

        Object actualObject = target;

        if (target instanceof TiViewProxy) {
            TiUIView intermediateObject = ((TiViewProxy) target).peekView();
            if (intermediateObject != null) {
                actualObject = intermediateObject.getNativeView();
                if (actualObject != null
                        && propertyName.equals(PROPERTY_BACKGROUND_COLOR)
                        && mIntValues.length == 1) {
                    // There is no "getBackgroundColor" on Android views,
                    // so we wrap it.
                    actualObject = new ViewWrapper((View) actualObject);
                }
            } else {
                Log.w(TAG, "View not available for animation.");
            }
        }

        if (actualObject == null) {
            Log.w(TAG, "Object not available for animation (null).");
            return;
        }

        switch (mPropertyType) {
            case FLOAT:
                animator = ObjectAnimator.ofFloat(actualObject,
                        propertyName, mFloatValues);
                break;
            case INT:
                animator = ObjectAnimator.ofInt(actualObject, propertyName,
                        mIntValues);
                break;
            case UNKNOWN:
                break;
        }

    }

    if (mRepeatCount != AndroidAnimation.NO_INT_VALUE) {
        animator.setRepeatCount(mRepeatCount);
    }

    if (mRepeatMode != AndroidAnimation.NO_INT_VALUE) {
        animator.setRepeatMode(mRepeatMode);
    }

    if (mEvaluator != AndroidAnimation.NO_INT_VALUE) {
        switch (mEvaluator) {
            case AndroidAnimation.INT_EVALUATOR:
                animator.setEvaluator(new IntEvaluator());
                break;
            case AndroidAnimation.FLOAT_EVALUATOR:
                animator.setEvaluator(new FloatEvaluator());
                break;
            case AndroidAnimation.ARGB_EVALUATOR:
                animator.setEvaluator(new ArgbEvaluator());
                break;
            default:
                Log.w(TAG, "Evaluator set to unknown value: " + mEvaluator);
        }
    }

    setAnimator(animator);

    super.setCommonAnimatorProperties();

}