WearableRecyclerView滚动不弯曲

Question

我的WearableRecyclerView，线条像三角形一样弯曲，而不像手表的主屏幕那样弯曲。我在代码中找不到任何错误。

ShareActivity：

private void initListView() {
    WearableRecyclerView recyclerView = findViewById(R.id.lVDevices);
    recyclerView.setEdgeItemsCenteringEnabled(true);
    final ScrollingLayoutCallback scrollingLayoutCallback =
            new ScrollingLayoutCallback();
    adapter = new ShareAdapter(new ShareAdapter.Callback() {
        @Override
        public void onDeviceClicked(int position, String deviceName) {
            onListItemClick(position, deviceName);
        }
    });
    recyclerView.setLayoutManager(
            new WearableLinearLayoutManager(this, scrollingLayoutCallback));
    recyclerView.setAdapter(adapter);
}

ScrollingLayoutCallback：

public class ScrollingLayoutCallback extends WearableLinearLayoutManager.LayoutCallback  {
private static final float MAX_ICON_PROGRESS = 0.65f;

@Override
public void onLayoutFinished(View child, RecyclerView parent) {

    // Figure out % progress from top to bottom
    float centerOffset = ((float) child.getHeight() / 2.0f) / (float) parent.getHeight();
    float yRelativeToCenterOffset = (child.getY() / parent.getHeight()) + centerOffset;

    // Normalize for center
    float mProgressToCenter = Math.abs(0.5f - yRelativeToCenterOffset);
    // Adjust to the maximum scale
    mProgressToCenter = Math.min(mProgressToCenter, MAX_ICON_PROGRESS);

    child.setScaleX(1 - mProgressToCenter);
    child.setScaleY(1 - mProgressToCenter);
}
}

ListView-XML

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:orientation="vertical">

<android.support.v4.widget.SwipeRefreshLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/refreshlayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/transparent">

    <android.support.wear.widget.WearableRecyclerView
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/lVDevices"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@android:color/transparent"
        android:scrollbars="vertical"/>
</android.support.v4.widget.SwipeRefreshLayout>
</RelativeLayout>

该行的XML

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
      android:id="@+id/lVDevices_row"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:background="@android:color/transparent"
      android:drawableStart="@drawable/point_img"
      android:layout_centerHorizontal="true"
      android:textSize="18sp">
</TextView>

回叫方法有问题吗？我的意思是计算中存在错误，因为它来自开发人员网站。

编辑1：ScrollingCallback类中的新数学

float centerOffset = ((float) child.getHeight() / 2.0f) / (float) parent.getHeight();
float yRelativeToCenterOffset = (child.getY() / parent.getHeight()) + centerOffset;

float progresstoCenter = (float) Math.sin(yRelativeToCenterOffset * Math.PI);

child.setScaleX(progresstoCenter);
child.setScaleY(progresstoCenter);

Answer 1

我已经创建了一个解决方案。

[像OP，我从不喜欢Android官方文档中提供的解决方案，该解决方案使列表元素沿三角形路径移动（从顶部中心到左中间的直线，然后从那里到底部的直线中心）。

解决方案很简单，使用trig将路径更改为半圆形。将CustomScrollingLayoutCallback替换为此：

class CustomScrollingLayoutCallback extends WearableLinearLayoutManager.LayoutCallback {
    @Override
    public void onLayoutFinished(View child, RecyclerView parent) {
        final float MAX_ICON_PROGRESS = 0.65f;

        try {
            float centerOffset              = ((float) child.getHeight() / 2.0f) / (float) parent.getHeight();
            float yRelativeToCenterOffset   = (child.getY() / parent.getHeight()) + centerOffset;

         // Normalize for center, adjusting to the maximum scale
            float progressToCenter          = Math.min(Math.abs(0.5f - yRelativeToCenterOffset), MAX_ICON_PROGRESS);

         // Follow a curved path, rather than triangular!
            progressToCenter                = (float)(Math.cos(progressToCenter * Math.PI * 0.70f));

            child.setScaleX (progressToCenter);
            child.setScaleY (progressToCenter);
        } catch (Exception ignored) {}
    }
}

[倒数第四行的“ ... * 0.70f”是通过反复试验确定的，并更改了该曲线以使其与官方Android Wear曲线最匹配。