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      1 /*
      2  * Copyright (C) 2009 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 com.android.contacts.ui;
     18 
     19 import com.android.contacts.model.EntityDelta;
     20 import com.android.contacts.model.ContactsSource.DataKind;
     21 import com.android.contacts.model.EntityDelta.ValuesDelta;
     22 import com.android.contacts.ui.widget.GenericEditorView;
     23 import com.android.contacts.ui.widget.KindSectionView;
     24 
     25 import android.os.Bundle;
     26 import android.os.Parcel;
     27 import android.os.Parcelable;
     28 
     29 /**
     30  * A class that provides unique view ids for {@link ContentEditorView}, {@link KindSectionView},
     31  * {@link GenericEditorView} and {@link EditView} on {@link EditContactActivity}.
     32  * It is used to assign a unique but consistent id to each view across {@link EditContactActivity}'s
     33  * lifecycle, so that we can re-construct view state (e.g. focused view) when the screen rotates.
     34  *
     35  * <p>This class is not thread safe.
     36  */
     37 public final class ViewIdGenerator implements Parcelable {
     38     private static final int INVALID_VIEW_ID = 0;
     39     private static final int INITIAL_VIEW_ID = 1;
     40 
     41     public static final int NO_VIEW_INDEX = -1;
     42 
     43     private int mNextId;
     44 
     45     /**
     46      * Used as a map from the "key" of the views to actual ids.  {@link #getId()} generates keys for
     47      * the views.
     48      */
     49     private Bundle mIdMap = new Bundle();
     50 
     51     private static final char KEY_SEPARATOR = '*';
     52 
     53     private final static StringBuilder sWorkStringBuilder = new StringBuilder();
     54 
     55     public ViewIdGenerator() {
     56         mNextId = INITIAL_VIEW_ID;
     57     }
     58 
     59     /** {@inheritDoc} */
     60     public int describeContents() {
     61         return 0;
     62     }
     63 
     64     /**
     65      * Returns an id for a view associated with specified contact field.
     66      *
     67      * @param entity {@link EntityDelta} associated with the view
     68      * @param kind {@link DataKind} associated with the view, or null if none exists.
     69      * @param values {@link ValuesDelta} associated with the view, or null if none exists.
     70      * @param viewIndex index of the view in the parent {@link Editor}, if it's a leave view.
     71      *     Otherwise, pass {@link #NO_VIEW_INDEX}.
     72      */
     73     public int getId(EntityDelta entity, DataKind kind, ValuesDelta values,
     74             int viewIndex) {
     75         final String k = getMapKey(entity, kind, values, viewIndex);
     76 
     77         int id = mIdMap.getInt(k, INVALID_VIEW_ID);
     78         if (id == INVALID_VIEW_ID) {
     79             // Make sure the new id won't conflict with auto-generated ids by masking with 0xffff.
     80             id = (mNextId++) & 0xFFFF;
     81             mIdMap.putInt(k, id);
     82         }
     83         return id;
     84     }
     85 
     86     private static String getMapKey(EntityDelta entity, DataKind kind, ValuesDelta values,
     87             int viewIndex) {
     88         sWorkStringBuilder.setLength(0);
     89         if (entity != null) {
     90             sWorkStringBuilder.append(entity.getValues().getId());
     91 
     92             if (kind != null) {
     93                 sWorkStringBuilder.append(KEY_SEPARATOR);
     94                 sWorkStringBuilder.append(kind.mimeType);
     95 
     96                 if (values != null) {
     97                     sWorkStringBuilder.append(KEY_SEPARATOR);
     98                     sWorkStringBuilder.append(values.getId());
     99 
    100                     if (viewIndex != NO_VIEW_INDEX) {
    101                         sWorkStringBuilder.append(KEY_SEPARATOR);
    102                         sWorkStringBuilder.append(viewIndex);
    103                     }
    104                 }
    105             }
    106         }
    107         return sWorkStringBuilder.toString();
    108     }
    109 
    110     /** {@Override} */
    111     public void writeToParcel(Parcel dest, int flags) {
    112         dest.writeInt(mNextId);
    113         dest.writeBundle(mIdMap);
    114     }
    115 
    116     private void readFromParcel(Parcel src) {
    117         mNextId = src.readInt();
    118         mIdMap = src.readBundle();
    119     }
    120 
    121     public static final Parcelable.Creator<ViewIdGenerator> CREATOR =
    122             new Parcelable.Creator<ViewIdGenerator>() {
    123         public ViewIdGenerator createFromParcel(Parcel in) {
    124             final ViewIdGenerator vig = new ViewIdGenerator();
    125             vig.readFromParcel(in);
    126             return vig;
    127         }
    128 
    129         public ViewIdGenerator[] newArray(int size) {
    130             return new ViewIdGenerator[size];
    131         }
    132     };
    133 }
    134