add bunch of new java APIs: mostly stubs or copied from AOSP

Many of these classes are only needed to be subclassed by androidx
support library, which is used in many android apps

src/api-impl/android/widget/PopupMenu.java

@@ -0,0 +1,146 @@
+/*
+ * Copyright (C) 2010 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 android.widget;
+
+import android.content.Context;
+import android.view.Gravity;
+import android.view.Menu;
+import android.view.MenuInflater;
+import android.view.MenuItem;
+import android.view.View;
+import android.view.View.OnTouchListener;
+import com.android.internal.R;
+
+/**
+ * A PopupMenu displays a {@link Menu} in a modal popup window anchored to a
+ * {@link View}. The popup will appear below the anchor view if there is room,
+ * or above it if there is not. If the IME is visible the popup will not
+ * overlap it until it is touched. Touching outside of the popup will dismiss
+ * it.
+ */
+
+public class PopupMenu {
+	private final Context mContext;
+	private final View mAnchor;
+	private OnMenuItemClickListener mMenuItemClickListener;
+	private OnDismissListener mOnDismissListener;
+	private OnTouchListener mDragListener;
+	/**
+	 * Constructor to create a new popup menu with an anchor view.
+	 *
+	 * @param context Context the popup menu is running in, through which it
+	 *        can access the current theme, resources, etc.
+	 * @param anchor Anchor view for this popup. The popup will appear below
+	 *        the anchor if there is room, or above it if there is not.
+	 */
+	public PopupMenu(Context context, View anchor) {
+		this(context, anchor, Gravity.NO_GRAVITY);
+	}
+	/**
+	 * Constructor to create a new popup menu with an anchor view and alignment
+	 * gravity.
+	 *
+	 * @param context Context the popup menu is running in, through which it
+	 *        can access the current theme, resources, etc.
+	 * @param anchor Anchor view for this popup. The popup will appear below
+	 *        the anchor if there is room, or above it if there is not.
+	 * @param gravity The {@link Gravity} value for aligning the popup with its
+	 *        anchor.
+	 */
+	public PopupMenu(Context context, View anchor, int gravity) {
+		this(context, anchor, gravity, R.attr.popupMenuStyle, 0);
+	}
+	/**
+	 * Constructor a create a new popup menu with a specific style.
+	 *
+	 * @param context Context the popup menu is running in, through which it
+	 *        can access the current theme, resources, etc.
+	 * @param anchor Anchor view for this popup. The popup will appear below
+	 *        the anchor if there is room, or above it if there is not.
+	 * @param gravity The {@link Gravity} value for aligning the popup with its
+	 *        anchor.
+	 * @param popupStyleAttr An attribute in the current theme that contains a
+	 *        reference to a style resource that supplies default values for
+	 *        the popup window. Can be 0 to not look for defaults.
+	 * @param popupStyleRes A resource identifier of a style resource that
+	 *        supplies default values for the popup window, used only if
+	 *        popupStyleAttr is 0 or can not be found in the theme. Can be 0
+	 *        to not look for defaults.
+	 */
+	public PopupMenu(Context context, View anchor, int gravity, int popupStyleAttr,
+			int popupStyleRes) {
+		mContext = context;
+		mAnchor = anchor;
+	}
+
+	/**
+	 * @return a {@link MenuInflater} that can be used to inflate menu items
+	 *         from XML into the menu returned by {@link #getMenu()}
+	 * @see #getMenu()
+	 */
+	public MenuInflater getMenuInflater() {
+		return new MenuInflater(mContext);
+	}
+
+	/**
+	 * Sets a listener that will be notified when the user selects an item from
+	 * the menu.
+	 *
+	 * @param listener the listener to notify
+	 */
+	public void setOnMenuItemClickListener(OnMenuItemClickListener listener) {
+		mMenuItemClickListener = listener;
+	}
+
+	/**
+	 * Sets a listener that will be notified when this menu is dismissed.
+	 *
+	 * @param listener the listener to notify
+	 */
+	public void setOnDismissListener(OnDismissListener listener) {
+		mOnDismissListener = listener;
+	}
+
+	/**
+	 * Interface responsible for receiving menu item click events if the items
+	 * themselves do not have individual item click listeners.
+	 */
+	public interface OnMenuItemClickListener {
+		/**
+		 * This method will be invoked when a menu item is clicked if the item
+		 * itself did not already handle the event.
+		 *
+		 * @param item the menu item that was clicked
+		 * @return {@code true} if the event was handled, {@code false}
+		 *         otherwise
+		 */
+		boolean onMenuItemClick(MenuItem item);
+	}
+
+	/**
+	 * Callback interface used to notify the application that the menu has closed.
+	 */
+	public interface OnDismissListener {
+		/**
+		 * Called when the associated menu has been dismissed.
+		 *
+		 * @param menu the popup menu that was dismissed
+		 */
+		void onDismiss(PopupMenu menu);
+	}
+
+}