Android 读取自身App中的数据库

    private String openDatabase() {
    private  final String  DATABASE_PATH  =  "/data/data/com.android.chrome/app_chrome/Default/History";

    SQLiteDatabase db;
        String res = "";
        try {
            String databaseFilename = DATABASE_PATH ;
            db = SQLiteDatabase.openOrCreateDatabase(databaseFilename, null);
        } catch (Exception e) {
            System.out.print("abccccdddd");
            e.printStackTrace();
        }
        Cursor cursor = db.rawQuery("select term from keyword_search_terms",null);
        while (cursor.moveToNext()){
            String record = cursor.getString(0);
            res+=record;

        }
        db.close();
        cursor.close();
        return res;
    }

调用的时候出现以下错误

08-14 07:59:56.392 27210-27210/? E/SQLiteLog: (5) database is locked
08-14 07:59:56.392 27210-27210/? E/SQLiteDatabase: Failed to open database '/data/data/com.android.chrome/app_chrome/Default/History'.
    android.database.sqlite.SQLiteDatabaseLockedException: database is locked (code 5): , while compiling: PRAGMA journal_mode

后来莫名其妙可以了