MenuPopupHelper.java revision 6c6f575423d6718c3ff322224c1520901ce881e1 
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.util.DisplayMetrics;
23import android.view.KeyEvent;
24import android.view.MenuItem;
25import android.view.View;
26import android.view.View.MeasureSpec;
27import android.widget.AdapterView;
28import android.widget.ListPopupWindow;
29import android.widget.PopupWindow;
30
31import java.lang.ref.WeakReference;
32
33/**
34 * @hide
35 */
36public class MenuPopupHelper implements AdapterView.OnItemClickListener, View.OnKeyListener {
37    private static final String TAG = "MenuPopupHelper";
38
39    private Context mContext;
40    private ListPopupWindow mPopup;
41    private MenuBuilder mMenu;
42    private int mPopupMaxWidth;
43    private WeakReference<View> mAnchorView;
44    private boolean mOverflowOnly;
45
46    private PopupWindow.OnDismissListener mDismissListener = new PopupWindow.OnDismissListener() {
47        public void onDismiss() {
48            mPopup = null;
49        }
50    };
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 show() {
75        // TODO Use a style from the theme here
76        mPopup = new ListPopupWindow(mContext, null, 0,
77                com.android.internal.R.style.Widget_Spinner);
78        mPopup.setOnItemClickListener(this);
79        mPopup.setOnDismissListener(mDismissListener);
80
81        final MenuAdapter adapter = mOverflowOnly ?
82                mMenu.getOverflowMenuAdapter(MenuBuilder.TYPE_POPUP) :
83                mMenu.getMenuAdapter(MenuBuilder.TYPE_POPUP);
84        mPopup.setAdapter(adapter);
85        mPopup.setModal(true);
86
87        if (mAnchorView != null) {
88            mPopup.setAnchorView(mAnchorView.get());
89        } else if (mMenu instanceof SubMenuBuilder) {
90            SubMenuBuilder subMenu = (SubMenuBuilder) mMenu;
91            final MenuItemImpl itemImpl = (MenuItemImpl) subMenu.getItem();
92            mPopup.setAnchorView(itemImpl.getItemView(MenuBuilder.TYPE_ACTION_BUTTON, null));
93        } else {
94            throw new IllegalStateException("MenuPopupHelper cannot be used without an anchor");
95        }
96
97        mPopup.setContentWidth(Math.min(measureContentWidth(adapter), mPopupMaxWidth));
98        mPopup.show();
99        mPopup.getListView().setOnKeyListener(this);
100    }
101
102    public void dismiss() {
103        if (isShowing()) {
104            mPopup.dismiss();
105        }
106    }
107
108    public boolean isShowing() {
109        return mPopup != null && mPopup.isShowing();
110    }
111
112    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
113        MenuItem item = null;
114        if (mOverflowOnly) {
115            item = mMenu.getOverflowItem(position);
116        } else {
117            item = mMenu.getItem(position);
118        }
119        mMenu.performItemAction(item, 0);
120        mPopup.dismiss();
121    }
122
123    public boolean onKey(View v, int keyCode, KeyEvent event) {
124        if (event.getAction() == KeyEvent.ACTION_UP && keyCode == KeyEvent.KEYCODE_MENU) {
125            dismiss();
126            return true;
127        }
128        return false;
129    }
130
131    private int measureContentWidth(MenuAdapter adapter) {
132        // Menus don't tend to be long, so this is more sane than it looks.
133        int width = 0;
134        View itemView = null;
135        final int widthMeasureSpec =
136            MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
137        final int heightMeasureSpec =
138            MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
139        final int count = adapter.getCount();
140        for (int i = 0; i < count; i++) {
141            itemView = adapter.getView(i, itemView, null);
142            itemView.measure(widthMeasureSpec, heightMeasureSpec);
143            width = Math.max(width, itemView.getMeasuredWidth());
144        }
145        return width;
146    }
147}
148