MenuPopupHelper.java revision 696cba573e651b0e4f18a4718627c8ccecb3bda0 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.internal.view.menu;
18
19import android.content.Context;
20import android.util.DisplayMetrics;
21import android.view.KeyEvent;
22import android.view.LayoutInflater;
23import android.view.View;
24import android.view.View.MeasureSpec;
25import android.view.ViewGroup;
26import android.view.ViewTreeObserver;
27import android.widget.AdapterView;
28import android.widget.BaseAdapter;
29import android.widget.ListAdapter;
30import android.widget.ListPopupWindow;
31import android.widget.PopupWindow;
32
33import java.util.ArrayList;
34
35/**
36 * Presents a menu as a small, simple popup anchored to another view.
37 * @hide
38 */
39public class MenuPopupHelper implements AdapterView.OnItemClickListener, View.OnKeyListener,
40        ViewTreeObserver.OnGlobalLayoutListener, PopupWindow.OnDismissListener,
41        View.OnAttachStateChangeListener, MenuPresenter {
42    private static final String TAG = "MenuPopupHelper";
43
44    static final int ITEM_LAYOUT = com.android.internal.R.layout.popup_menu_item_layout;
45
46    private Context mContext;
47    private LayoutInflater mInflater;
48    private ListPopupWindow mPopup;
49    private MenuBuilder mMenu;
50    private int mPopupMaxWidth;
51    private View mAnchorView;
52    private boolean mOverflowOnly;
53    private ViewTreeObserver mTreeObserver;
54
55    private MenuAdapter mAdapter;
56
57    private Callback mPresenterCallback;
58
59    public MenuPopupHelper(Context context, MenuBuilder menu) {
60        this(context, menu, null, false);
61    }
62
63    public MenuPopupHelper(Context context, MenuBuilder menu, View anchorView) {
64        this(context, menu, anchorView, false);
65    }
66
67    public MenuPopupHelper(Context context, MenuBuilder menu,
68            View anchorView, boolean overflowOnly) {
69        mContext = context;
70        mInflater = LayoutInflater.from(context);
71        mMenu = menu;
72        mOverflowOnly = overflowOnly;
73
74        final DisplayMetrics metrics = context.getResources().getDisplayMetrics();
75        mPopupMaxWidth = metrics.widthPixels / 2;
76
77        mAnchorView = anchorView;
78
79        menu.addMenuPresenter(this);
80    }
81
82    public void setAnchorView(View anchor) {
83        mAnchorView = anchor;
84    }
85
86    public void show() {
87        if (!tryShow()) {
88            throw new IllegalStateException("MenuPopupHelper cannot be used without an anchor");
89        }
90    }
91
92    public boolean tryShow() {
93        mPopup = new ListPopupWindow(mContext, null, com.android.internal.R.attr.popupMenuStyle);
94        mPopup.setOnDismissListener(this);
95        mPopup.setOnItemClickListener(this);
96
97        mAdapter = new MenuAdapter(mMenu);
98        mPopup.setAdapter(mAdapter);
99        mPopup.setModal(true);
100
101        View anchor = mAnchorView;
102        if (anchor != null) {
103            final boolean addGlobalListener = mTreeObserver == null;
104            mTreeObserver = anchor.getViewTreeObserver(); // Refresh to latest
105            if (addGlobalListener) mTreeObserver.addOnGlobalLayoutListener(this);
106            anchor.addOnAttachStateChangeListener(this);
107            mPopup.setAnchorView(anchor);
108        } else {
109            return false;
110        }
111
112        mPopup.setContentWidth(Math.min(measureContentWidth(mAdapter), mPopupMaxWidth));
113        mPopup.setInputMethodMode(PopupWindow.INPUT_METHOD_NOT_NEEDED);
114        mPopup.show();
115        mPopup.getListView().setOnKeyListener(this);
116        return true;
117    }
118
119    public void dismiss() {
120        if (isShowing()) {
121            mPopup.dismiss();
122        }
123    }
124
125    public void onDismiss() {
126        mPopup = null;
127        if (mTreeObserver != null) {
128            if (!mTreeObserver.isAlive()) mTreeObserver = mAnchorView.getViewTreeObserver();
129            mTreeObserver.removeGlobalOnLayoutListener(this);
130            mTreeObserver = null;
131        }
132        mAnchorView.removeOnAttachStateChangeListener(this);
133    }
134
135    public boolean isShowing() {
136        return mPopup != null && mPopup.isShowing();
137    }
138
139    @Override
140    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
141        MenuAdapter adapter = mAdapter;
142        adapter.mAdapterMenu.performItemAction(adapter.getItem(position), 0);
143    }
144
145    public boolean onKey(View v, int keyCode, KeyEvent event) {
146        if (event.getAction() == KeyEvent.ACTION_UP && keyCode == KeyEvent.KEYCODE_MENU) {
147            dismiss();
148            return true;
149        }
150        return false;
151    }
152
153    private int measureContentWidth(ListAdapter adapter) {
154        // Menus don't tend to be long, so this is more sane than it looks.
155        int width = 0;
156        View itemView = null;
157        int itemType = 0;
158        final int widthMeasureSpec =
159            MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
160        final int heightMeasureSpec =
161            MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
162        final int count = adapter.getCount();
163        for (int i = 0; i < count; i++) {
164            final int positionType = adapter.getItemViewType(i);
165            if (positionType != itemType) {
166                itemType = positionType;
167                itemView = null;
168            }
169            itemView = adapter.getView(i, itemView, null);
170            itemView.measure(widthMeasureSpec, heightMeasureSpec);
171            width = Math.max(width, itemView.getMeasuredWidth());
172        }
173        return width;
174    }
175
176    @Override
177    public void onGlobalLayout() {
178        if (isShowing()) {
179            final View anchor = mAnchorView;
180            if (anchor == null || !anchor.isShown()) {
181                dismiss();
182            } else if (isShowing()) {
183                // Recompute window size and position
184                mPopup.show();
185            }
186        }
187    }
188
189    @Override
190    public void onViewAttachedToWindow(View v) {
191    }
192
193    @Override
194    public void onViewDetachedFromWindow(View v) {
195        if (mTreeObserver != null) {
196            if (!mTreeObserver.isAlive()) mTreeObserver = v.getViewTreeObserver();
197            mTreeObserver.removeGlobalOnLayoutListener(this);
198        }
199        v.removeOnAttachStateChangeListener(this);
200    }
201
202    @Override
203    public void initForMenu(Context context, MenuBuilder menu) {
204        // Don't need to do anything; we added as a presenter in the constructor.
205    }
206
207    @Override
208    public MenuView getMenuView(ViewGroup root) {
209        throw new UnsupportedOperationException("MenuPopupHelpers manage their own views");
210    }
211
212    @Override
213    public void updateMenuView(boolean cleared) {
214        if (mAdapter != null) mAdapter.notifyDataSetChanged();
215    }
216
217    @Override
218    public void setCallback(Callback cb) {
219        mPresenterCallback = cb;
220    }
221
222    @Override
223    public boolean onSubMenuSelected(SubMenuBuilder subMenu) {
224        if (subMenu.hasVisibleItems()) {
225            MenuPopupHelper subPopup = new MenuPopupHelper(mContext, subMenu, mAnchorView, false);
226            subPopup.setCallback(mPresenterCallback);
227            if (subPopup.tryShow()) {
228                if (mPresenterCallback != null) {
229                    mPresenterCallback.onOpenSubMenu(subMenu);
230                }
231                return true;
232            }
233        }
234        return false;
235    }
236
237    @Override
238    public void onCloseMenu(MenuBuilder menu, boolean allMenusAreClosing) {
239        // Only care about the (sub)menu we're presenting.
240        if (menu != mMenu) return;
241
242        dismiss();
243        if (mPresenterCallback != null) {
244            mPresenterCallback.onCloseMenu(menu, allMenusAreClosing);
245        }
246    }
247
248    @Override
249    public boolean flagActionItems() {
250        return false;
251    }
252
253    private class MenuAdapter extends BaseAdapter {
254        private MenuBuilder mAdapterMenu;
255
256        public MenuAdapter(MenuBuilder menu) {
257            mAdapterMenu = menu;
258        }
259
260        public int getCount() {
261            ArrayList<MenuItemImpl> items = mOverflowOnly ?
262                    mAdapterMenu.getNonActionItems() : mAdapterMenu.getVisibleItems();
263            return items.size();
264        }
265
266        public MenuItemImpl getItem(int position) {
267            ArrayList<MenuItemImpl> items = mOverflowOnly ?
268                    mAdapterMenu.getNonActionItems() : mAdapterMenu.getVisibleItems();
269            return items.get(position);
270        }
271
272        public long getItemId(int position) {
273            // Since a menu item's ID is optional, we'll use the position as an
274            // ID for the item in the AdapterView
275            return position;
276        }
277
278        public View getView(int position, View convertView, ViewGroup parent) {
279            if (convertView == null) {
280                convertView = mInflater.inflate(ITEM_LAYOUT, parent, false);
281            }
282
283            MenuView.ItemView itemView = (MenuView.ItemView) convertView;
284            itemView.initialize(getItem(position), 0);
285            return convertView;
286        }
287    }
288}
289