在滚动时更改水平回收器视图项的比例

Question

我想要像下图这样的回收者视图。意味着我希望在水平回收器视图中最大中间回收器视图项的高度和宽度。

Answer 1

我从链接中找到了解决方案，您可以相应地遵循它。

public class CenterZoomLayoutManager extends LinearLayoutManager {

 private final float mShrinkAmount = 0.15f;
 private final float mShrinkDistance = 0.9f;

public CenterZoomLayoutManager(Context context) {
    super(context);
}

public CenterZoomLayoutManager(Context context, int orientation, boolean reverseLayout) {
    super(context, orientation, reverseLayout);
}


@Override
public int scrollVerticallyBy(int dy, RecyclerView.Recycler recycler, RecyclerView.State state) {
    int orientation = getOrientation();
    if (orientation == VERTICAL) {
        int scrolled = super.scrollVerticallyBy(dy, recycler, state);
        float midpoint = getHeight() / 2.f;
        float d0 = 0.f;
        float d1 = mShrinkDistance * midpoint;
        float s0 = 1.f;
        float s1 = 1.f - mShrinkAmount;
        for (int i = 0; i < getChildCount(); i++) {
            View child = getChildAt(i);
            float childMidpoint =
                    (getDecoratedBottom(child) + getDecoratedTop(child)) / 2.f;
            float d = Math.min(d1, Math.abs(midpoint - childMidpoint));
            float scale = s0 + (s1 - s0) * (d - d0) / (d1 - d0);
            child.setScaleX(scale);
            child.setScaleY(scale);
        }
        return scrolled;
    } else {
        return 0;
    }
}

@Override
public int scrollHorizontallyBy(int dx, RecyclerView.Recycler recycler, RecyclerView.State state) {
    int orientation = getOrientation();
    if (orientation == HORIZONTAL) {
        int scrolled = super.scrollHorizontallyBy(dx, recycler, state);

        float midpoint = getWidth() / 2.f;
        float d0 = 0.f;
        float d1 = mShrinkDistance * midpoint;
        float s0 = 1.f;
        float s1 = 1.f - mShrinkAmount;
        for (int i = 0; i < getChildCount(); i++) {
            View child = getChildAt(i);
            float childMidpoint =
                    (getDecoratedRight(child) + getDecoratedLeft(child)) / 2.f;
            float d = Math.min(d1, Math.abs(midpoint - childMidpoint));
            float scale = s0 + (s1 - s0) * (d - d0) / (d1 - d0);
            child.setScaleX(scale);
            child.setScaleY(scale);
        }
        return scrolled;
    } else {
        return 0;
    }

}

}