1 files changed, 131 insertions, 0 deletions
diff --git a/RotaryPlayground/src/com/android/car/rotaryplayground/PopupWindowFragment.java b/RotaryPlayground/src/com/android/car/rotaryplayground/PopupWindowFragment.java
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index 0000000..f2ae91a
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+++ b/RotaryPlayground/src/com/android/car/rotaryplayground/PopupWindowFragment.java
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.car.rotaryplayground;
+
+import android.os.Bundle;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.view.ViewTreeObserver;
+import android.widget.ArrayAdapter;
+import android.widget.Button;
+import android.widget.ListPopupWindow;
+import android.widget.ListView;
+import android.widget.Toast;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.Fragment;
+
+import com.android.car.ui.FocusParkingView;
+
+/** Fragment to demo a popup window. */
+public class PopupWindowFragment extends Fragment {
+
+    private static final String[] ACTIONS = {"Action 1", "Action 2", "Action 3"};
+    private static final int WINDOW_WIDTH = 300;
+    private static final int WINDOW_HEIGHT = 400;
+
+    @NonNull
+    private ListPopupWindow mPopupWindow;
+    @Nullable
+    private ListView mListView;
+
+    @Override
+    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container,
+            @Nullable Bundle savedInstanceState) {
+        View view = inflater.inflate(R.layout.popup_window_fragment, container, false);
+        Button overflow = view.findViewById(R.id.overflow);
+
+        mPopupWindow = new ListPopupWindow(getActivity());
+        mPopupWindow.setAdapter(new ArrayAdapter<>(getActivity(), R.layout.list_item, ACTIONS));
+        mPopupWindow.setAnchorView(overflow);
+        mPopupWindow.setWidth(WINDOW_WIDTH);
+        mPopupWindow.setHeight(WINDOW_HEIGHT);
+        mPopupWindow.setModal(true);
+        mPopupWindow.setOnItemClickListener((parent, v, position, id) -> {
+            Toast.makeText(getActivity(), ACTIONS[position], Toast.LENGTH_SHORT).show();
+            mPopupWindow.dismiss();
+        });
+
+        overflow.setOnClickListener((v) -> {
+            mPopupWindow.show();
+            mListView = mPopupWindow.getListView();
+            if (mListView != null && mListView.isFocused()) {
+                initRotaryMode();
+            }
+        });
+
+        return view;
+    }
+
+    /**
+     * Initializes the popup window to support rotary controller rotations and nudges.
+     * <p>
+     * In rotary mode the first focusable element in the ListView should be focused automatically
+     * when the popup window shows up. However, in {@link ListPopupWindow#show}, Android framework
+     * creates the ListView, sets it focusable, then focuses on it automatically. What's worse,
+     * ListView doesn't handle focusSearch() properly, causing rotation fails once it's focused.
+     * To work around it, move focus to its first focusable element, then set the ListView
+     * to not be focusable.
+     */
+    private void initRotaryMode() {
+        if (mListView == null) {
+            return;
+        }
+
+        // Add a FocusParkingView to prevent rotary controller rotation wrap-around.
+        View root = mListView.getRootView();
+        if (root instanceof ViewGroup) {
+            ViewGroup rootView = (ViewGroup) root;
+            FocusParkingView fpv = new FocusParkingView(getActivity());
+
+            // This popup window can be dismissed by controller nudges.
+            fpv.setOnPopupWindowDismiss(() -> mPopupWindow.dismiss());
+
+            rootView.addView(fpv);
+        }
+
+        // At this time the elements in the list are not loaded yet. Because there is no callbacks
+        // to notify whether the elements are loaded, use an OnPreDrawListener as workaround.
+        ViewTreeObserver.OnPreDrawListener listeners[] =
+                new ViewTreeObserver.OnPreDrawListener[1];
+        listeners[0] = (() -> {
+            boolean focusInitialized = false;
+            for (int i = 0; i < mListView.getChildCount(); i++) {
+                View child = mListView.getChildAt(i);
+                if (child != null) {
+                    // Because the elements are set focusable, they'll steal click events from the
+                    // list, so they need to handle the events on their own.
+                    int position = i;
+                    child.setOnClickListener(v -> mPopupWindow.performItemClick(position));
+
+                    // Move focus to the first focusable element and set the list non-focussable.
+                    if (!focusInitialized) {
+                        focusInitialized = child.requestFocus();
+                        if (focusInitialized) {
+                            mListView.setFocusable(false);
+                            mListView.getViewTreeObserver().removeOnPreDrawListener(listeners[0]);
+                        }
+                    }
+                }
+            }
+            return true;
+        });
+        mListView.getViewTreeObserver().addOnPreDrawListener(listeners[0]);
+    }
+}