Android ContactsProvider源码分析

Android源码目录packages\providers下的应用是下载，通话等内置基本应用提供数据存储和操作的provider应用，本文章将针对ContactsProvider源码的架构和实现展开分析。（注：本文使用使用android4.0版本进行分析）

1、架构设计

ContactsProvider中数据操作基类是AbstractContactsProvider.java（参见frameworks\ex\common\java\com\android\common\content\SQLiteContentProvider.java），它继承ContentProvider.java实现SQLiteTransactionListener.java，类结构如下图所示：



图 1 provider结构图

该类是抽象基类，在里面实现了父类的insert、delete和update三个抽象方法，在这三个方法中在其中使用了事务对数据库进行操作。该类设计时，使用了模板模式模板方法为insertInTransaction，updateInTransaction和deleteInTransaction。该类在对数据库进行事务操作的同时，对子类开放了onRollback，onCommit等事物回调方法，子类可以根据自己的业务特点进行扩展。增删改查的调用过程如下图2
3 4所示：



图2 插入操作



图 3 更新操作



图 4 删除操作

在整个设计中有两个类继承了AbstractContactsProvider.java，一个是ContactsProvider2.java，我们在调用系统的联系人数据时基本都是调用该类，里面封装了所有联系人的数据操作。第二个是ProfileProvider.java，该类是ContactsProvider2.java的委托类。这三个类的类间关系如下图5所示：



图 5 类间关系图

类ContactsTransaction.java是对事务的管理类，主要对进行的事务进行管理，类似一个事务池。是AbstractContactsProvider.java中事务处理的核心类。
DataRowHandler.java是数据处理抽象类，实现了对数据的增删改操作，子类有如下几个：

DataRowHandlerForCommonDataKind.java
DataRowHandlerForCustomMimetype.java
DataRowHandlerForEmail.java
DataRowHandlerForGroupMembership.java
DataRowHandlerForIm.java
DataRowHandlerForNickname.java
DataRowHandlerForNote.java
DataRowHandlerForOrganization.java
DataRowHandlerForPhoneNumber.java
DataRowHandlerForPhoto.java
DataRowHandlerForStructuredName.java
DataRowHandlerForStructuredPostal.java

这些子类在ContactsProvider2#initDataRowHandlers中初始化

private void initDataRowHandlers(Map<String, DataRowHandler> handlerMap,
ContactsDatabaseHelper dbHelper, ContactAggregator contactAggregator,
PhotoStore photoStore) {
Context context = getContext();
handlerMap.put(Email.CONTENT_ITEM_TYPE,
new DataRowHandlerForEmail(context, dbHelper, contactAggregator));
handlerMap.put(Im.CONTENT_ITEM_TYPE,
new DataRowHandlerForIm(context, dbHelper, contactAggregator));
handlerMap.put(Organization.CONTENT_ITEM_TYPE,
new DataRowHandlerForOrganization(context, dbHelper, contactAggregator));
handlerMap.put(Phone.CONTENT_ITEM_TYPE,
new DataRowHandlerForPhoneNumber(context, dbHelper, contactAggregator));
handlerMap.put(Nickname.CONTENT_ITEM_TYPE,
new DataRowHandlerForNickname(context, dbHelper, contactAggregator));
handlerMap.put(StructuredName.CONTENT_ITEM_TYPE,
new DataRowHandlerForStructuredName(context, dbHelper, contactAggregator,
mNameSplitter, mNameLookupBuilder));
handlerMap.put(StructuredPostal.CONTENT_ITEM_TYPE,
new DataRowHandlerForStructuredPostal(context, dbHelper, contactAggregator,
mPostalSplitter));
handlerMap.put(GroupMembership.CONTENT_ITEM_TYPE,
new DataRowHandlerForGroupMembership(context, dbHelper, contactAggregator,
mGroupIdCache));
handlerMap.put(Photo.CONTENT_ITEM_TYPE,
new DataRowHandlerForPhoto(context, dbHelper, contactAggregator, photoStore));
handlerMap.put(Note.CONTENT_ITEM_TYPE,
new DataRowHandlerForNote(context, dbHelper, contactAggregator));
}

这些子类在getDataRowHandler方法中中通过mimetype进行调用：

public DataRowHandler getDataRowHandler(final String mimeType) {
if (inProfileMode()) {
return getDataRowHandlerForProfile(mimeType);
}
DataRowHandler handler = mDataRowHandlers.get(mimeType);
if (handler == null) {
handler = new DataRowHandlerForCustomMimetype(
getContext(), mContactsHelper, mContactAggregator, mimeType);
mDataRowHandlers.put(mimeType, handler);
}
return handler;
}

getDataRowHandler方法在insertData，deleteData和updateData方法中被调用。

/**
* Inserts an item in the data table
*
* @param values the values for the new row
* @return the row ID of the newly created row
*/
private long insertData(ContentValues values, boolean callerIsSyncAdapter) {
long id = 0;
mValues.clear();
mValues.putAll(values);

long rawContactId = mValues.getAsLong(Data.RAW_CONTACT_ID);

// Replace package with internal mapping
final String packageName = mValues.getAsString(Data.RES_PACKAGE);
if (packageName != null) {
mValues.put(DataColumns.PACKAGE_ID, mDbHelper.get().getPackageId(packageName));
}
mValues.remove(Data.RES_PACKAGE);

// Replace mimetype with internal mapping
final String mimeType = mValues.getAsString(Data.MIMETYPE);
if (TextUtils.isEmpty(mimeType)) {
throw new IllegalArgumentException(Data.MIMETYPE + " is required");
}

mValues.put(DataColumns.MIMETYPE_ID, mDbHelper.get().getMimeTypeId(mimeType));
mValues.remove(Data.MIMETYPE);

DataRowHandler rowHandler = getDataRowHandler(mimeType);
id = rowHandler.insert(mActiveDb.get(), mTransactionContext.get(), rawContactId, mValues);
if (!callerIsSyncAdapter) {
mTransactionContext.get().markRawContactDirty(rawContactId);
}
mTransactionContext.get().rawContactUpdated(rawContactId);
return id;
}

所有数据的mimetype都被存储在表Tables.MIMETYPES中，该只有两个字段_id和mimetype。

db.execSQL("CREATE TABLE " + Tables.MIMETYPES + " ("
+ MimetypesColumns._ID + " INTEGER PRIMARY KEY AUTOINCREMENT,"
+ MimetypesColumns.MIMETYPE + " TEXT NOT NULL" + ");");

Tables.MIMETYPES表数据的存储是在ContactsDatabaseHelper#lookupAndCacheId中进行的，具体调用过程如下图 6 所示：



图 6 mimetype数据调用流程图

2、表结构

ContactsProvider 中共创建了25张表，

public static final String CONTACTS = "contacts";
public static final String RAW_CONTACTS = "raw_contacts";
public static final String STREAM_ITEMS = "stream_items";
public static final String STREAM_ITEM_PHOTOS = "stream_item_photos";
public static final String PHOTO_FILES = "photo_files";
public static final String PACKAGES = "packages";
public static final String MIMETYPES = "mimetypes";
public static final String PHONE_LOOKUP = "phone_lookup";
public static final String NAME_LOOKUP = "name_lookup";
public static final String AGGREGATION_EXCEPTIONS = "agg_exceptions";
public static final String SETTINGS = "settings";
public static final String DATA = "data";
public static final String GROUPS = "groups";
public static final String PRESENCE = "presence";
public static final String AGGREGATED_PRESENCE = "agg_presence";
public static final String NICKNAME_LOOKUP = "nickname_lookup";
public static final String CALLS = "calls";
public static final String STATUS_UPDATES = "status_updates";
public static final String PROPERTIES = "properties";
public static final String ACCOUNTS = "accounts";
public static final String VISIBLE_CONTACTS = "visible_contacts";
public static final String DIRECTORIES = "directories";
public static final String DEFAULT_DIRECTORY = "default_directory";
public static final String SEARCH_INDEX = "search_index";
public static final String VOICEMAIL_STATUS = "voicemail_status";

这些表数据对开发者开放的api在 \frameworks\base\core\java\android\provider\文件夹下，

CallLog.java
Contacts.java
ContactsContract.java
SocialContract.java
SyncConstValue.java
VoicemailContract.java

由于数据查询涉及多个表间关系，大量数据的查询都是通过视图来完成的，创建了如下8个视图，而这几个视图是大家在调用api进行查询时显示的数据：

public interface Views {
public static final String DATA = "view_data";
public static final String RAW_CONTACTS = "view_raw_contacts";
public static final String CONTACTS = "view_contacts";
public static final String ENTITIES = "view_entities";
public static final String RAW_ENTITIES = "view_raw_entities";
public static final String GROUPS = "view_groups";
public static final String DATA_USAGE_STAT = "view_data_usage_stat";
public static final String STREAM_ITEMS = "view_stream_items";
}

4、总结

ContactsProvder是provider源码中数据处理和架构比较全面的一个应用，可以将它的架构核心抽离出来供大家参考和借鉴，以下类构成了整个架构的核心类，可以重点研究：

AbstractContactsProvider.java
ContactAggregator.java
ContactsDatabaseHelper.java
ContactsProvider2.java
ContactsTransaction.java
TransactionContext.java