Android系统应用Mms之短信会话列表加载流程一

1. ConversationList短息会话列表界面
1. 开始进行加载
ConversationList: 
protected void onStart(){
    ...
    // 进行异步查询
    startAsyncQuery();
}

private void startAsyncQuery() {
    ...
    // 加载消息
    mLoaderFragment.reLoadMessage(THREAD_LIST_QUERY_TOKEN, // token: 1701
                                  Conversation.sAllThreadsUri,// 查询的Uri: content://mms-sms/conversations&simple=true
                                  Conversation.ALL_THREADS_PROJECTION,// 查询的字段
                                  null, null, 
                                  Conversations.DEFAULT_SORT_ORDER);
    ...
}

2. 进入到MessageLoaderFragment, 进行加载
MessageLoaderFragment:
public void reLoadMessage(int loadId, Uri uri, String[] projection,
            String selection, String[] selectionArgs, String orderBy) {
    ...
    // 进行异步加载
    getLoaderManager().restartLoader(loadId, null, mMessageLoaderListener);        
}

3. 进入到MmsSmsProvider中执行查询流程
MmsSmsProvider:
public Cursor query(Uri uri, String[] projection,
            String selection, String[] selectionArgs, String sortOrder) {
    ...
    switch(URI_MATCHER.match(uri)) {
        ...
        case URI_CONVERSATIONS:
            String simple = uri.getQueryParameter("simple");
            if ((simple != null) && simple.equals("true")) {
                String threadType = uri.getQueryParameter("thread_type"); // 获取会话类型
                if (!TextUtils.isEmpty(threadType)) {
                    selection = concatSelections(selection, Threads.TYPE + "=" + threadType);
                }
                // 获取简单会话
                cursor = getSimpleConversations(projection, selection, selectionArgs, sortOrder);
            } else {
                cursor = getConversations(projection, selection, sortOrder);
            }
            break;        
        ...
    }
    ...
    return cursor;    
}

private Cursor getSimpleConversations(String[] projection, String selection,
            String[] selectionArgs, String sortOrder) {
    // 到此处已完成会话的查询, 接下来看数据的填充
    return mOpenHelper.getReadableDatabase().query(TABLE_THREADS, // threads数据库 
                                                   projection, selection, 
                                                   selectionArgs, null, null,
                                                   " date DESC");        
}

4. 数据加载完成后回调到MessageLoaderFragment$LoaderManager.LoaderCallbacks<Cursor>中
MessageLoaderFragment$LoaderManager.LoaderCallbacks<Cursor>:
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
    ...
    // 数据加载完成回调到ConversationList中
    mListener.onMessageLoaded(data, loader);
}

5. 数据回调到ConversationList$MessageLoaderFragmentListener中
ConversationList$MessageLoaderFragmentListener:
public void onMessageLoaded(Cursor cursor, Loader<Cursor> loader) {
    // 更新UI
    mListAdapter.changeCursor(cursor);
    ... 
}

短信会话列表加载涉及到的数据库:
MmsSmsDatabaseHelper: 
数据库名: MmsSmsProvider:
static final String TABLE_THREADS = "threads"
数据库的创建:
private void createCommonTables(SQLiteDatabase db) {
    ...
    db.execSQL("CREATE TABLE threads (" +
               Threads._ID + " INTEGER PRIMARY KEY AUTOINCREMENT," +// id
               Threads.DATE + " INTEGER DEFAULT 0," + // 时间
               Threads.MESSAGE_COUNT + " INTEGER DEFAULT 0," + // 消息数量
               Threads.RECIPIENT_IDS + " TEXT," + // 接受者ID
               Threads.SNIPPET + " TEXT," + // 片段
               Threads.SNIPPET_CHARSET + " INTEGER DEFAULT 0," + // 片段编码
               Threads.READ + " INTEGER DEFAULT 1," + // 是否已读
               Threads.TYPE + " INTEGER DEFAULT 0," + // 类型
               Threads.ERROR + " INTEGER DEFAULT 0," + // 是否有错
               Threads.HAS_ATTACHMENT + " INTEGER DEFAULT 0," + // 是否有附件
               Threads.RECIPIENT_ADDRESSES + " TEXT, " + // 接受者地址
               Threads.RECIPIENT_NAMES + " TEXT ); "); // 接受者姓名    
}