Java tutorial
/* * 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.annotation.MenuRes; import android.annotation.TestApi; import android.annotation.UnsupportedAppUsage; 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; import com.android.internal.view.menu.MenuBuilder; import com.android.internal.view.menu.MenuPopupHelper; import com.android.internal.view.menu.ShowableListMenu; /** * 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 { @UnsupportedAppUsage private final Context mContext; private final MenuBuilder mMenu; private final View mAnchor; @UnsupportedAppUsage private final MenuPopupHelper mPopup; 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; mMenu = new MenuBuilder(context); mMenu.setCallback(new MenuBuilder.Callback() { @Override public boolean onMenuItemSelected(MenuBuilder menu, MenuItem item) { if (mMenuItemClickListener != null) { return mMenuItemClickListener.onMenuItemClick(item); } return false; } @Override public void onMenuModeChange(MenuBuilder menu) { } }); mPopup = new MenuPopupHelper(context, mMenu, anchor, false, popupStyleAttr, popupStyleRes); mPopup.setGravity(gravity); mPopup.setOnDismissListener(new PopupWindow.OnDismissListener() { @Override public void onDismiss() { if (mOnDismissListener != null) { mOnDismissListener.onDismiss(PopupMenu.this); } } }); } /** * Sets the gravity used to align the popup window to its anchor view. * <p> * If the popup is showing, calling this method will take effect only * the next time the popup is shown. * * @param gravity the gravity used to align the popup window * @see #getGravity() */ public void setGravity(int gravity) { mPopup.setGravity(gravity); } /** * @return the gravity used to align the popup window to its anchor view * @see #setGravity(int) */ public int getGravity() { return mPopup.getGravity(); } /** * Returns an {@link OnTouchListener} that can be added to the anchor view * to implement drag-to-open behavior. * <p> * When the listener is set on a view, touching that view and dragging * outside of its bounds will open the popup window. Lifting will select * the currently touched list item. * <p> * Example usage: * <pre> * PopupMenu myPopup = new PopupMenu(context, myAnchor); * myAnchor.setOnTouchListener(myPopup.getDragToOpenListener()); * </pre> * * @return a touch listener that controls drag-to-open behavior */ public OnTouchListener getDragToOpenListener() { if (mDragListener == null) { mDragListener = new ForwardingListener(mAnchor) { @Override protected boolean onForwardingStarted() { show(); return true; } @Override protected boolean onForwardingStopped() { dismiss(); return true; } @Override public ShowableListMenu getPopup() { // This will be null until show() is called. return mPopup.getPopup(); } }; } return mDragListener; } /** * Returns the {@link Menu} associated with this popup. Populate the * returned Menu with items before calling {@link #show()}. * * @return the {@link Menu} associated with this popup * @see #show() * @see #getMenuInflater() */ public Menu getMenu() { return mMenu; } /** * @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); } /** * Inflate a menu resource into this PopupMenu. This is equivalent to * calling {@code popupMenu.getMenuInflater().inflate(menuRes, popupMenu.getMenu())}. * * @param menuRes Menu resource to inflate */ public void inflate(@MenuRes int menuRes) { getMenuInflater().inflate(menuRes, mMenu); } /** * Show the menu popup anchored to the view specified during construction. * * @see #dismiss() */ public void show() { mPopup.show(); } /** * Dismiss the menu popup. * * @see #show() */ public void dismiss() { mPopup.dismiss(); } /** * 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); } /** * Returns the {@link ListView} representing the list of menu items in the currently showing * menu. * * @return The view representing the list of menu items. * @hide */ @TestApi public ListView getMenuListView() { if (!mPopup.isShowing()) { return null; } return mPopup.getPopup().getListView(); } }