Android 禁用操作列表的滚动效果

我有一个像这样的

GuidedStepSupportFragment

片段

public class SampleStepFragment extends GuidedStepSupportFragment {

    @NonNull
    @Override
    public GuidanceStylist.Guidance onCreateGuidance(Bundle savedInstanceState) {
        String title = "Title";
        String breadcrumb = "Breadcrumb";
        String description = "Description";
        Drawable icon = getActivity().getDrawable(R.drawable.ic_videocam_black_24dp);

        return new GuidanceStylist.Guidance(title, description, breadcrumb, icon);
    }

    @Override
    public void onCreateActions(@NonNull List<GuidedAction> actions, Bundle savedInstanceState) {

        addAction(actions, ACTION_CONTINUE, "Action1");
        addAction(actions, ACTION_BACK, "Action2");

    }
}

公共类SampleStepFragment扩展了GuidedStepSupportFragment{
@非空
@凌驾
public GuidanceStylist.guidanceoncreateguidance（Bundle savedInstanceState）{
字符串title=“title”；
String breadcrumb=“breadcrumb”；
String description=“description”；
可绘制图标=getActivity（）.getDrawable（R.Drawable.ic_videocam_black_24dp）；
返回新的GuidanceStylist.Guidance（标题、描述、面包屑、图标）；
}
@凌驾
public void onCreateActions（@NonNull List actions，Bundle savedInstanceState）{
添加行动（行动，行动，继续，“行动1”）；
添加操作（操作，操作返回，“操作2”）；
}
}

问题：当我滚动动作列表时，它显示如下

但是我想要这样的东西

如何在操作列表中禁用此效果

---

谢谢

我做到了，这不容易弄清楚

没有支持的方法可以做到这一点，因为实际上实现这一点的API是包私有的，或者故意隐藏起来不供公众使用。（您可以自己完成，但最终只能从leanback库复制类。）

解决方案： 因此，由于API是隐藏的，我们只需使用反射来公开

setFocusScrollStrategy

方法，并将其设置为

FOCUS\u SCROLL\u ITEM

---

但是我们不能立即执行此操作，因为如果没有默认的滚动设置，列表项将弹出到布局的顶部，并且不会保持居中。所以我加了500毫秒的延迟，这太可怕了。。。如果您设法找到触发此事件的最佳时间，请告诉我。

示例中不清楚错误与预期效果之间的区别，或者至少我看不到。这是一个对齐问题吗？作为旁注：谢谢你提出了这个有趣的问题，在研究过程中，我修复了在我自己的电视应用程序中滚动的问题，原因是：）

@Override
public void onCreateActions(@NonNull List<GuidedAction> actions, Bundle savedInstanceState) {

    addAction(actions, GuidedAction.ACTION_ID_CONTINUE, "Action1");
    addAction(actions, GuidedAction.ACTION_ID_CANCEL, "Action2");

    // Run code delayed on mainThread (any other/better method can/should be used)
    // It's delayed because if focus scroll is disabled, the list will stick to the top of the layout
    new Handler(Looper.getMainLooper()).postDelayed(this::disableFocusScroll, 500);
}

private void disableFocusScroll() {
    RecyclerView.LayoutManager layoutManager = SampleStepFragment.this.getGuidedActionsStylist().getActionsGridView().getLayoutManager();
    try {
        Method method = layoutManager.getClass().getMethod("setFocusScrollStrategy", int.class);
        method.invoke(layoutManager, 1 /* FOCUS_SCROLL_ITEM */);
    } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
        Log.e(TAG, "disableFocusScroll: ", e);
    }
}

/**
 * Always keep focused item at a aligned position.  Developer can use
 * WINDOW_ALIGN_XXX and ITEM_ALIGN_XXX to define how focused item is aligned.
 * In this mode, the last focused position will be remembered and restored when focus
 * is back to the view.
 * @hide
 */
@RestrictTo(LIBRARY_GROUP)
public final static int FOCUS_SCROLL_ALIGNED = 0;

/**
 * Scroll to make the focused item inside client area.
 * @hide
 */
@RestrictTo(LIBRARY_GROUP)
public final static int FOCUS_SCROLL_ITEM = 1;

/**
 * Scroll a page of items when focusing to item outside the client area.
 * The page size matches the client area size of RecyclerView.
 * @hide
 */
@RestrictTo(LIBRARY_GROUP)
public final static int FOCUS_SCROLL_PAGE = 2;