MenuPopupHelper.java revision 4afd62b18c52a55371ab923d54f93615ad68fd7a 
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 com.android.internal.view.menu.MenuBuilder.MenuAdapter;
20
21import android.content.Context;
22import android.os.Handler;
23import android.util.DisplayMetrics;
24import android.view.KeyEvent;
25import android.view.MenuItem;
26import android.view.View;
27import android.view.View.MeasureSpec;
28import android.view.ViewTreeObserver;
29import android.widget.AdapterView;
30import android.widget.ListPopupWindow;
31import android.widget.PopupWindow;
32
33import java.lang.ref.WeakReference;
34
35/**
36 * @hide
37 */
38public class MenuPopupHelper implements AdapterView.OnItemClickListener, View.OnKeyListener,
39        ViewTreeObserver.OnGlobalLayoutListener, PopupWindow.OnDismissListener,
40        View.OnAttachStateChangeListener {
41    private static final String TAG = "MenuPopupHelper";
42
43    private Context mContext;
44    private ListPopupWindow mPopup;
45    private MenuBuilder mMenu;
46    private int mPopupMaxWidth;
47    private View mAnchorView;
48    private boolean mOverflowOnly;
49    private ViewTreeObserver mTreeObserver;
50
51    private final Handler mHandler = new Handler();
52
53    public MenuPopupHelper(Context context, MenuBuilder menu) {
54        this(context, menu, null, false);
55    }
56
57    public MenuPopupHelper(Context context, MenuBuilder menu, View anchorView) {
58        this(context, menu, anchorView, false);
59    }
60
61    public MenuPopupHelper(Context context, MenuBuilder menu,
62            View anchorView, boolean overflowOnly) {
63        mContext = context;
64        mMenu = menu;
65        mOverflowOnly = overflowOnly;
66
67        final DisplayMetrics metrics = context.getResources().getDisplayMetrics();
68        mPopupMaxWidth = metrics.widthPixels / 2;
69
70        mAnchorView = anchorView;
71    }
72
73    public void setAnchorView(View anchor) {
74        mAnchorView = anchor;
75    }
76
77    public void show() {
78        if (!tryShow()) {
79            throw new IllegalStateException("MenuPopupHelper cannot be used without an anchor");
80        }
81    }
82
83    public boolean tryShow() {
84        mPopup = new ListPopupWindow(mContext, null, com.android.internal.R.attr.popupMenuStyle);
85        mPopup.setOnItemClickListener(this);
86        mPopup.setOnDismissListener(this);
87
88        final MenuAdapter adapter = mOverflowOnly ?
89                mMenu.getOverflowMenuAdapter(MenuBuilder.TYPE_POPUP) :
90                mMenu.getMenuAdapter(MenuBuilder.TYPE_POPUP);
91        mPopup.setAdapter(adapter);
92        mPopup.setModal(true);
93
94        View anchor = mAnchorView;
95        if (anchor == null && mMenu instanceof SubMenuBuilder) {
96            SubMenuBuilder subMenu = (SubMenuBuilder) mMenu;
97            final MenuItemImpl itemImpl = (MenuItemImpl) subMenu.getItem();
98            anchor = itemImpl.getItemView(MenuBuilder.TYPE_ACTION_BUTTON, null);
99            mAnchorView = anchor;
100        }
101
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(adapter), 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    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
140        if (!isShowing()) return;
141
142        MenuItem item = null;
143        if (mOverflowOnly) {
144            item = mMenu.getOverflowItem(position);
145        } else {
146            item = mMenu.getVisibleItems().get(position);
147        }
148        dismiss();
149
150        final MenuItem performItem = item;
151        mHandler.post(new Runnable() {
152            public void run() {
153                mMenu.performItemAction(performItem, 0);
154            }
155        });
156    }
157
158    public boolean onKey(View v, int keyCode, KeyEvent event) {
159        if (event.getAction() == KeyEvent.ACTION_UP && keyCode == KeyEvent.KEYCODE_MENU) {
160            dismiss();
161            return true;
162        }
163        return false;
164    }
165
166    private int measureContentWidth(MenuAdapter adapter) {
167        // Menus don't tend to be long, so this is more sane than it looks.
168        int width = 0;
169        View itemView = null;
170        int itemType = 0;
171        final int widthMeasureSpec =
172            MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
173        final int heightMeasureSpec =
174            MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
175        final int count = adapter.getCount();
176        for (int i = 0; i < count; i++) {
177            final int positionType = adapter.getItemViewType(i);
178            if (positionType != itemType) {
179                itemType = positionType;
180                itemView = null;
181            }
182            itemView = adapter.getView(i, itemView, null);
183            itemView.measure(widthMeasureSpec, heightMeasureSpec);
184            width = Math.max(width, itemView.getMeasuredWidth());
185        }
186        return width;
187    }
188
189    @Override
190    public void onGlobalLayout() {
191        if (isShowing()) {
192            final View anchor = mAnchorView;
193            if (anchor == null || !anchor.isShown()) {
194                dismiss();
195            } else if (isShowing()) {
196                // Recompute window size and position
197                mPopup.show();
198            }
199        }
200    }
201
202    @Override
203    public void onViewAttachedToWindow(View v) {
204    }
205
206    @Override
207    public void onViewDetachedFromWindow(View v) {
208        if (mTreeObserver != null) {
209            if (!mTreeObserver.isAlive()) mTreeObserver = v.getViewTreeObserver();
210            mTreeObserver.removeGlobalOnLayoutListener(this);
211        }
212        v.removeOnAttachStateChangeListener(this);
213    }
214}
215