Java tutorial
/* * Copyright (C) 2016 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.support.v7.widget; import android.content.Context; import android.content.res.Configuration; import android.content.res.Resources; import android.os.Build; import android.support.annotation.NonNull; import android.support.v4.view.ViewCompat; import android.support.v4.widget.PopupWindowCompat; import android.support.v7.view.menu.ListMenuItemView; import android.support.v7.view.menu.MenuAdapter; import android.support.v7.view.menu.MenuBuilder; import android.transition.Transition; import android.util.AttributeSet; import android.util.Log; import android.view.KeyEvent; import android.view.MenuItem; import android.view.MotionEvent; import android.view.View; import android.widget.HeaderViewListAdapter; import android.widget.ListAdapter; import android.widget.PopupWindow; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; /** * A MenuPopupWindow represents the popup window for menu. * * MenuPopupWindow is mostly same as ListPopupWindow, but it has customized * behaviors specific to menus, * * @hide */ public class MenuPopupWindow extends ListPopupWindow implements MenuItemHoverListener { private static final String TAG = "MenuPopupWindow"; private static Method sSetTouchModalMethod; static { try { sSetTouchModalMethod = PopupWindow.class.getDeclaredMethod("setTouchModal", boolean.class); } catch (NoSuchMethodException e) { Log.i(TAG, "Could not find method setTouchModal() on PopupWindow. Oh well."); } } private MenuItemHoverListener mHoverListener; public MenuPopupWindow(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { super(context, attrs, defStyleAttr, defStyleRes); } @Override DropDownListView createDropDownListView(Context context, boolean hijackFocus) { MenuDropDownListView view = new MenuDropDownListView(context, hijackFocus); view.setHoverListener(this); return view; } public void setEnterTransition(Object enterTransition) { if (Build.VERSION.SDK_INT >= 23) { mPopup.setEnterTransition((Transition) enterTransition); } } public void setExitTransition(Object exitTransition) { if (Build.VERSION.SDK_INT >= 23) { mPopup.setExitTransition((Transition) exitTransition); } } public void setHoverListener(MenuItemHoverListener hoverListener) { mHoverListener = hoverListener; } /** * Set whether this window is touch modal or if outside touches will be sent to * other windows behind it. */ public void setTouchModal(final boolean touchModal) { if (sSetTouchModalMethod != null) { try { sSetTouchModalMethod.invoke(mPopup, touchModal); } catch (Exception e) { Log.i(TAG, "Could not invoke setTouchModal() on PopupWindow. Oh well."); } } } @Override public void onItemHoverEnter(@NonNull MenuBuilder menu, @NonNull MenuItem item) { // Forward up the chain if (mHoverListener != null) { mHoverListener.onItemHoverEnter(menu, item); } } @Override public void onItemHoverExit(@NonNull MenuBuilder menu, @NonNull MenuItem item) { // Forward up the chain if (mHoverListener != null) { mHoverListener.onItemHoverExit(menu, item); } } /** * @hide */ public static class MenuDropDownListView extends DropDownListView { final int mAdvanceKey; final int mRetreatKey; private MenuItemHoverListener mHoverListener; private MenuItem mHoveredMenuItem; public MenuDropDownListView(Context context, boolean hijackFocus) { super(context, hijackFocus); final Resources res = context.getResources(); final Configuration config = res.getConfiguration(); if (Build.VERSION.SDK_INT >= 17 && ViewCompat.LAYOUT_DIRECTION_RTL == config.getLayoutDirection()) { mAdvanceKey = KeyEvent.KEYCODE_DPAD_LEFT; mRetreatKey = KeyEvent.KEYCODE_DPAD_RIGHT; } else { mAdvanceKey = KeyEvent.KEYCODE_DPAD_RIGHT; mRetreatKey = KeyEvent.KEYCODE_DPAD_LEFT; } } public void setHoverListener(MenuItemHoverListener hoverListener) { mHoverListener = hoverListener; } public void clearSelection() { setSelection(INVALID_POSITION); } @Override public boolean onKeyDown(int keyCode, KeyEvent event) { ListMenuItemView selectedItem = (ListMenuItemView) getSelectedView(); if (selectedItem != null && keyCode == mAdvanceKey) { if (selectedItem.isEnabled() && selectedItem.getItemData().hasSubMenu()) { performItemClick(selectedItem, getSelectedItemPosition(), getSelectedItemId()); } return true; } else if (selectedItem != null && keyCode == mRetreatKey) { setSelection(INVALID_POSITION); // Close only the top-level menu. ((MenuAdapter) getAdapter()).getAdapterMenu().close(false /* closeAllMenus */); return true; } return super.onKeyDown(keyCode, event); } @Override public boolean onHoverEvent(MotionEvent ev) { // Dispatch any changes in hovered item index to the listener. if (mHoverListener != null) { // The adapter may be wrapped. Adjust the index if necessary. final int headersCount; final MenuAdapter menuAdapter; final ListAdapter adapter = getAdapter(); if (adapter instanceof HeaderViewListAdapter) { final HeaderViewListAdapter headerAdapter = (HeaderViewListAdapter) adapter; headersCount = headerAdapter.getHeadersCount(); menuAdapter = (MenuAdapter) headerAdapter.getWrappedAdapter(); } else { headersCount = 0; menuAdapter = (MenuAdapter) adapter; } // Find the menu item for the view at the event coordinates. MenuItem menuItem = null; if (ev.getAction() != MotionEvent.ACTION_HOVER_EXIT) { final int position = pointToPosition((int) ev.getX(), (int) ev.getY()); if (position != INVALID_POSITION) { final int itemPosition = position - headersCount; if (itemPosition >= 0 && itemPosition < menuAdapter.getCount()) { menuItem = menuAdapter.getItem(itemPosition); } } } final MenuItem oldMenuItem = mHoveredMenuItem; if (oldMenuItem != menuItem) { final MenuBuilder menu = menuAdapter.getAdapterMenu(); if (oldMenuItem != null) { mHoverListener.onItemHoverExit(menu, oldMenuItem); } mHoveredMenuItem = menuItem; if (menuItem != null) { mHoverListener.onItemHoverEnter(menu, menuItem); } } } return super.onHoverEvent(ev); } } }