MenuPopupHelper.java revision aa0b92ce2b51987e9c864164234fe968ab5b9311 
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.view.ViewTreeObserver;
28import android.widget.AdapterView;
29import android.widget.ListPopupWindow;
30import android.widget.PopupWindow;
31
32import java.lang.ref.WeakReference;
33
34/**
35 * @hide
36 */
37public class MenuPopupHelper implements AdapterView.OnItemClickListener, View.OnKeyListener,
38        ViewTreeObserver.OnGlobalLayoutListener, PopupWindow.OnDismissListener {
39    private static final String TAG = "MenuPopupHelper";
40
41    private Context mContext;
42    private ListPopupWindow mPopup;
43    private MenuBuilder mMenu;
44    private int mPopupMaxWidth;
45    private WeakReference<View> mAnchorView;
46    private boolean mOverflowOnly;
47    private ViewTreeObserver mTreeObserver;
48
49    public MenuPopupHelper(Context context, MenuBuilder menu) {
50        this(context, menu, null, false);
51    }
52
53    public MenuPopupHelper(Context context, MenuBuilder menu, View anchorView) {
54        this(context, menu, anchorView, false);
55    }
56
57    public MenuPopupHelper(Context context, MenuBuilder menu,
58            View anchorView, boolean overflowOnly) {
59        mContext = context;
60        mMenu = menu;
61        mOverflowOnly = overflowOnly;
62
63        final DisplayMetrics metrics = context.getResources().getDisplayMetrics();
64        mPopupMaxWidth = metrics.widthPixels / 2;
65
66        if (anchorView != null) {
67            mAnchorView = new WeakReference<View>(anchorView);
68        }
69    }
70
71    public void show() {
72        mPopup = new ListPopupWindow(mContext, null, com.android.internal.R.attr.popupMenuStyle);
73        mPopup.setOnItemClickListener(this);
74        mPopup.setOnDismissListener(this);
75
76        final MenuAdapter adapter = mOverflowOnly ?
77                mMenu.getOverflowMenuAdapter(MenuBuilder.TYPE_POPUP) :
78                mMenu.getMenuAdapter(MenuBuilder.TYPE_POPUP);
79        mPopup.setAdapter(adapter);
80        mPopup.setModal(true);
81
82        View anchor = mAnchorView != null ? mAnchorView.get() : null;
83        if (anchor == null && mMenu instanceof SubMenuBuilder) {
84            SubMenuBuilder subMenu = (SubMenuBuilder) mMenu;
85            final MenuItemImpl itemImpl = (MenuItemImpl) subMenu.getItem();
86            anchor = itemImpl.getItemView(MenuBuilder.TYPE_ACTION_BUTTON, null);
87            mAnchorView = new WeakReference<View>(anchor);
88        }
89
90        if (anchor != null) {
91            mTreeObserver = anchor.getViewTreeObserver();
92            mTreeObserver.addOnGlobalLayoutListener(this);
93            mPopup.setAnchorView(anchor);
94        } else {
95            throw new IllegalStateException("MenuPopupHelper cannot be used without an anchor");
96        }
97
98        mPopup.setContentWidth(Math.min(measureContentWidth(adapter), mPopupMaxWidth));
99        mPopup.setInputMethodMode(PopupWindow.INPUT_METHOD_NOT_NEEDED);
100        mPopup.show();
101        mPopup.getListView().setOnKeyListener(this);
102    }
103
104    public void dismiss() {
105        if (isShowing()) {
106            mPopup.dismiss();
107        }
108    }
109
110    public void onDismiss() {
111        mPopup = null;
112        if (mTreeObserver != null) {
113            mTreeObserver.removeGlobalOnLayoutListener(MenuPopupHelper.this);
114            mTreeObserver = null;
115        }
116    }
117
118    public boolean isShowing() {
119        return mPopup != null && mPopup.isShowing();
120    }
121
122    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
123        MenuItem item = null;
124        if (mOverflowOnly) {
125            item = mMenu.getOverflowItem(position);
126        } else {
127            item = mMenu.getItem(position);
128        }
129        mMenu.performItemAction(item, 0);
130        dismiss();
131    }
132
133    public boolean onKey(View v, int keyCode, KeyEvent event) {
134        if (event.getAction() == KeyEvent.ACTION_UP && keyCode == KeyEvent.KEYCODE_MENU) {
135            dismiss();
136            return true;
137        }
138        return false;
139    }
140
141    private int measureContentWidth(MenuAdapter adapter) {
142        // Menus don't tend to be long, so this is more sane than it looks.
143        int width = 0;
144        View itemView = null;
145        final int widthMeasureSpec =
146            MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
147        final int heightMeasureSpec =
148            MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
149        final int count = adapter.getCount();
150        for (int i = 0; i < count; i++) {
151            itemView = adapter.getView(i, itemView, null);
152            itemView.measure(widthMeasureSpec, heightMeasureSpec);
153            width = Math.max(width, itemView.getMeasuredWidth());
154        }
155        return width;
156    }
157
158    @Override
159    public void onGlobalLayout() {
160        if (!isShowing()) {
161            mTreeObserver.removeGlobalOnLayoutListener(this);
162            mTreeObserver = null;
163        } else {
164            final View anchor = mAnchorView != null ? mAnchorView.get() : null;
165            if (anchor != null && !anchor.isShown()) {
166                dismiss();
167            } else {
168                // Recompute window size and position
169                mPopup.show();
170            }
171        }
172    }
173}
174