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      1 /*
      2  * Copyright (C) 2007 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 
     17 package android.view.menu;
     18 
     19 import android.app.Activity;
     20 import android.os.Bundle;
     21 import android.util.ListScenario;
     22 import android.util.SparseArray;
     23 import android.view.Menu;
     24 import android.view.MenuItem;
     25 
     26 /**
     27  * Utility base class for creating various Menu scenarios. Configurable by the
     28  * number of menu items. Used @link {@link ListScenario} as a reference.
     29  */
     30 public class MenuScenario extends Activity implements MenuItem.OnMenuItemClickListener {
     31     private Params mParams = new Params();
     32     private Menu mMenu;
     33     private MenuItem[] mItems;
     34     private boolean[] mWasItemClicked;
     35 
     36     @Override
     37     protected void onCreate(Bundle icicle) {
     38         super.onCreate(icicle);
     39 
     40         dispatchInitParams();
     41     }
     42 
     43     private void dispatchInitParams() {
     44         onInitParams(mParams);
     45         onParamsChanged();
     46     }
     47 
     48     public void setParams(Params params) {
     49         mParams = params;
     50         onParamsChanged();
     51     }
     52 
     53     public void onParamsChanged() {
     54         mItems = new MenuItem[mParams.numItems];
     55         mWasItemClicked = new boolean[mParams.numItems];
     56     }
     57 
     58     @Override
     59     public boolean onCreateOptionsMenu(Menu menu) {
     60         // Safe to hold on to
     61         mMenu = menu;
     62 
     63         if (!mParams.shouldShowMenu) return false;
     64 
     65         MenuItem item;
     66         for (int i = 0; i < mParams.numItems; i++) {
     67             if ((item = onAddMenuItem(menu, i)) == null) {
     68                 // Add a default item for this position if the subclasses
     69                 // haven't
     70                 CharSequence givenTitle = mParams.itemTitles.get(i);
     71                 item = menu.add(0, 0, 0, (givenTitle != null) ? givenTitle : ("Item " + i));
     72             }
     73 
     74             if (item != null) {
     75                 mItems[i] = item;
     76 
     77                 if (mParams.listenForClicks) {
     78                     item.setOnMenuItemClickListener(this);
     79                 }
     80             }
     81 
     82         }
     83 
     84         return true;
     85     }
     86 
     87     @Override
     88     public boolean onPrepareOptionsMenu(Menu menu) {
     89         // Safe to hold on to
     90         mMenu = menu;
     91 
     92         return mParams.shouldShowMenu;
     93     }
     94 
     95     /**
     96      * Override this to add an item to the menu.
     97      *
     98      * @param itemPosition The position of the item to add (only for your
     99      *            reference).
    100      * @return The item that was added to the menu, or null if nothing was
    101      *         added.
    102      */
    103     protected MenuItem onAddMenuItem(Menu menu, int itemPosition) {
    104         return null;
    105     }
    106 
    107     /**
    108      * Override this to set the parameters for the scenario. Call through to super first.
    109      *
    110      * @param params
    111      */
    112     protected void onInitParams(Params params) {
    113     }
    114 
    115     public Menu getMenu() {
    116         return mMenu;
    117     }
    118 
    119     public boolean onMenuItemClick(MenuItem item) {
    120         final int position = findItemPosition(item);
    121         if (position < 0) return false;
    122 
    123         mWasItemClicked[position] = true;
    124 
    125         return true;
    126     }
    127 
    128     public boolean wasItemClicked(int position) {
    129         return mWasItemClicked[position];
    130     }
    131 
    132     /**
    133      * Finds the position for a given Item.
    134      *
    135      * @param item The item to find.
    136      * @return The position, or -1 if not found.
    137      */
    138     public int findItemPosition(MenuItem item) {
    139         // Could create reverse mapping, but optimizations aren't important (yet :P)
    140         for (int i = 0; i < mParams.numItems; i++) {
    141             if (mItems[i] == item) return i;
    142         }
    143 
    144         return -1;
    145     }
    146 
    147     public static class Params {
    148         // Using as data structure, so no m prefix
    149         private boolean shouldShowMenu = true;
    150         private int numItems = 10;
    151         private boolean listenForClicks = true;
    152         private SparseArray<CharSequence> itemTitles = new SparseArray<CharSequence>();
    153 
    154         public Params setShouldShowMenu(boolean shouldShowMenu) {
    155             this.shouldShowMenu = shouldShowMenu;
    156             return this;
    157         }
    158 
    159         public Params setNumItems(int numItems) {
    160             this.numItems = numItems;
    161             return this;
    162         }
    163 
    164         public Params setListenForClicks(boolean listenForClicks) {
    165             this.listenForClicks = listenForClicks;
    166             return this;
    167         }
    168 
    169         public Params setItemTitle(int itemPos, CharSequence title) {
    170             itemTitles.put(itemPos, title);
    171             return this;
    172         }
    173     }
    174 }
    175