垂直网格视图的焦点处理

Question

在这里，VerticalGridView(VG(将填充一些数据。VG接收焦点按D-PAD键向上/向下，它工作正常。但问题是，当焦点位于网格中的第零项并且用户按 D-PAD 键控焦点必须设置在 VG 之外的视图之一，即 ll_exit(xml 文件中提到的 id(，但当前焦点不会转到所述视图。请让我知道我如何解决这个问题。

我尝试设置 android：nextFocusUp="@id/ll_exit"，但它没有移动并尝试在活动级别实现 onKeyUp 方法，如下所示

@Override
    public boolean onKeyUp(int keyCode, KeyEvent event) {
        switch (keyCode) {
            case KeyEvent.KEYCODE_DPAD_UP:
                Log.d(TAG, "onKeyUp: " + event.getAction());
                GenresFragment fragment = (GenresFragment) getSupportFragmentManager().findFragmentById(R.id.fragment_genre);
                int pos = fragment.getVerticalGridView().getSelectedPosition();
                if (pos == 0) {
                    fragment.getLlExit().requestFocus();
                }
                return true;
            default:
                return super.onKeyUp(keyCode, event);
        }
    }

但这里的问题是，当我在 VG 中的第一个项目并突然按下向上键按钮时，它会转到我需要关注的视图。那是xml文件中ll_exit视图

<b>main_layout.xml</b>
    <?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/ll_root"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <LinearLayout
            android:id="@+id/ll_toolbar"
            android:layout_width="@dimen/select_genre_fragment_width"
            android:layout_height="@dimen/select_genre_toolbar_height"
            android:orientation="horizontal">
            <TextView
                android:id="@+id/tv_all_channels"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"/>
            <LinearLayout
                android:id="@+id/ll_genres"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"/>
            <LinearLayout
                android:id="@+id/ll_exit"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"/>
        </LinearLayout>
        <android.support.v17.leanback.widget.VerticalGridView
            android:id="@+id/vg_genres"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_below="@id/ll_toolbar"
            android:nextFocusUp="@id/ll_exit" />
    </RelativeLayout>

Answer 1

尝试将以下 XML 属性添加到 VG

app:focusOutEnd="true"
app:focusOutFront="true"

它对我有用！

Answer 2

尝试将以下 XML 属性添加到 LinearLayout 视图ll_exit

android:focusable="true"
android:focusableInTouchMode="true"

Answer 3

可能的方法：尝试将线性布局ll_toolbar设置为

android:focusable="true"
android:focusableInTouchMode="true"
android:descendantFocusability="afterDescendants"

或尝试：

View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused, View.FOCUS_UP);
if (nextFocused != null) {
    nextFocused.requestFocus();
}

如果没有有效的解决方案，只需像这样扩展垂直网格视图

public class SampleVerticalGridView extends VerticalGridView implements FocusInterceptor{

    private static final String TAG = "SampleVerticalGridView";
    private View focusUp;
    private View focusDown;
    // constructors and stuff
    ...
    public void setNextFocusViews(View focusUp, View focusdown) {
        this.focusUp = focusUp;
        this.focusdown = focusdown;
    }
    @Override
    public View focusSearch(View focused, int direction) {
        if (direction == View.FOCUS_UP && focusUp != null) {
            return focusUp;
        } else if (direction == View.FOCUS_DOWN && focusDown != null) {
            return focusDown;
        }
        return super.focusSearch(focused, direction);
    }
    ...
}