Android viewPager2实现画廊效果

直接上代码

public class ScaleAlphaPageTransformer implements ViewPager2.PageTransformer {

    public static final float MAX_SCALE = 1.0f;
    public static final float MIN_SCALE = 0.8f;
    public static final float MAX_ALPHA = 1.0f;
    public static final float MIN_ALPHA = 0.7f;

    private boolean alpha = true;
    private boolean scale = true;

    @Override
    public void transformPage(View page, float position) {

        //翻转效果
        float scaleFactor = Math.max(MIN_SCALE, 1 - Math.abs(position));
        float rotate = 20 * Math.abs(position);
        float transla = 20 * Math.abs(position);
        if (position > 0) {
            page.setScaleX(scaleFactor);
            page.setScaleY(scaleFactor);
            page.setRotationY(-rotate);
            page.setTranslationX(-transla);
        } else {
            page.setScaleX(scaleFactor);
            page.setScaleY(scaleFactor);
            page.setRotationY(rotate);
            page.setTranslationX(transla);
        }

        //无效果
//        if (position < -1) {
//            position = -1;
//        } else if (position > 1) {
//            position = 1;
//        }

        float tempScale = position < 0 ? 1 + position : 1 - position;
        if (scale) {
            float slope = (MAX_SCALE - MIN_SCALE) / 1;
            //一个公式
            float scaleValue = MIN_SCALE + tempScale * slope;
            page.setScaleX(scaleValue);
            page.setScaleY(scaleValue);
        }
        if (alpha) {
            //模糊
            float alope = (MAX_ALPHA - MIN_ALPHA) / 1;
            float alphaValue = MIN_ALPHA + tempScale * alope;
            page.setAlpha(alphaValue);
        }
    }

    /***
     * 设置是否模糊和改变大小
     * @param alpha
     * @param scale
     */
    public void setType(boolean alpha, boolean scale) {
        this.alpha = alpha;
        this.scale = scale;
    }

}

public class RecAdapter extends RecyclerView.Adapter {

    protected LayoutInflater inflater;
    protected Context context;
    protected List