MenuPopupHelper.java revision e2b03a62e5014ea60e24a989544fa549b493a520 
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    private static final String TAG = "MenuPopupHelper";
41
42    private Context mContext;
43    private ListPopupWindow mPopup;
44    private MenuBuilder mMenu;
45    private int mPopupMaxWidth;
46    private WeakReference<View> mAnchorView;
47    private boolean mOverflowOnly;
48    private ViewTreeObserver mTreeObserver;
49
50    private final Handler mHandler = new Handler();
51
52    public MenuPopupHelper(Context context, MenuBuilder menu) {
53        this(context, menu, null, false);
54    }
55
56    public MenuPopupHelper(Context context, MenuBuilder menu, View anchorView) {
57        this(context, menu, anchorView, false);
58    }
59
60    public MenuPopupHelper(Context context, MenuBuilder menu,
61            View anchorView, boolean overflowOnly) {
62        mContext = context;
63        mMenu = menu;
64        mOverflowOnly = overflowOnly;
65
66        final DisplayMetrics metrics = context.getResources().getDisplayMetrics();
67        mPopupMaxWidth = metrics.widthPixels / 2;
68
69        if (anchorView != null) {
70            mAnchorView = new WeakReference<View>(anchorView);
71        }
72    }
73
74    public void setAnchorView(View anchor) {
75        mAnchorView = new WeakReference<View>(anchor);
76    }
77
78    public void show() {
79        if (!tryShow()) {
80            throw new IllegalStateException("MenuPopupHelper cannot be used without an anchor");
81        }
82    }
83
84    public boolean tryShow() {
85        mPopup = new ListPopupWindow(mContext, null, com.android.internal.R.attr.popupMenuStyle);
86        mPopup.setOnItemClickListener(this);
87        mPopup.setOnDismissListener(this);
88
89        final MenuAdapter adapter = mOverflowOnly ?
90                mMenu.getOverflowMenuAdapter(MenuBuilder.TYPE_POPUP) :
91                mMenu.getMenuAdapter(MenuBuilder.TYPE_POPUP);
92        mPopup.setAdapter(adapter);
93        mPopup.setModal(true);
94
95        View anchor = mAnchorView != null ? mAnchorView.get() : null;
96        if (anchor == null && mMenu instanceof SubMenuBuilder) {
97            SubMenuBuilder subMenu = (SubMenuBuilder) mMenu;
98            final MenuItemImpl itemImpl = (MenuItemImpl) subMenu.getItem();
99            anchor = itemImpl.getItemView(MenuBuilder.TYPE_ACTION_BUTTON, null);
100            mAnchorView = new WeakReference<View>(anchor);
101        }
102
103        if (anchor != null) {
104            mTreeObserver = anchor.getViewTreeObserver();
105            mTreeObserver.addOnGlobalLayoutListener(this);
106            mPopup.setAnchorView(anchor);
107        } else {
108            return false;
109        }
110
111        mPopup.setContentWidth(Math.min(measureContentWidth(adapter), mPopupMaxWidth));
112        mPopup.setInputMethodMode(PopupWindow.INPUT_METHOD_NOT_NEEDED);
113        mPopup.show();
114        mPopup.getListView().setOnKeyListener(this);
115        return true;
116    }
117
118    public void dismiss() {
119        if (isShowing()) {
120            mPopup.dismiss();
121        }
122    }
123
124    public void onDismiss() {
125        mPopup = null;
126        if (mTreeObserver != null) {
127            mTreeObserver.removeGlobalOnLayoutListener(MenuPopupHelper.this);
128            mTreeObserver = null;
129        }
130    }
131
132    public boolean isShowing() {
133        return mPopup != null && mPopup.isShowing();
134    }
135
136    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
137        MenuItem item = null;
138        if (mOverflowOnly) {
139            item = mMenu.getOverflowItem(position);
140        } else {
141            item = mMenu.getVisibleItems().get(position);
142        }
143        dismiss();
144
145        final MenuItem performItem = item;
146        mHandler.post(new Runnable() {
147            public void run() {
148                mMenu.performItemAction(performItem, 0);
149            }
150        });
151    }
152
153    public boolean onKey(View v, int keyCode, KeyEvent event) {
154        if (event.getAction() == KeyEvent.ACTION_UP && keyCode == KeyEvent.KEYCODE_MENU) {
155            dismiss();
156            return true;
157        }
158        return false;
159    }
160
161    private int measureContentWidth(MenuAdapter adapter) {
162        // Menus don't tend to be long, so this is more sane than it looks.
163        int width = 0;
164        View itemView = null;
165        int itemType = 0;
166        final int widthMeasureSpec =
167            MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
168        final int heightMeasureSpec =
169            MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
170        final int count = adapter.getCount();
171        for (int i = 0; i < count; i++) {
172            final int positionType = adapter.getItemViewType(i);
173            if (positionType != itemType) {
174                itemType = positionType;
175                itemView = null;
176            }
177            itemView = adapter.getView(i, itemView, null);
178            itemView.measure(widthMeasureSpec, heightMeasureSpec);
179            width = Math.max(width, itemView.getMeasuredWidth());
180        }
181        return width;
182    }
183
184    @Override
185    public void onGlobalLayout() {
186        if (!isShowing()) {
187            mTreeObserver.removeGlobalOnLayoutListener(this);
188            mTreeObserver = null;
189        } else {
190            final View anchor = mAnchorView != null ? mAnchorView.get() : null;
191            if (anchor != null && !anchor.isShown()) {
192                dismiss();
193            } else {
194                // Recompute window size and position
195                mPopup.show();
196            }
197        }
198    }
199}
200