Question

最近我正在尝试构建一个可以使用Android Studio打开现有SQLite数据库的应用程序，我仍然是Android编程的新手......当我在寻找打开数据库的方式时，我发现了这个链接：

http://www.reigndesign.com/blog/using-your-own-sqlite-database-in-android-applications/

顺便说一下，我还是不知道如何将链接上的代码实现到我的项目中...这里有没有人能够帮助制作关于如何使用它的示例（或者至少给出一些指导）？只是一个简单的例子对我来说真的足够了... thx before：）

Answer 1

您可以在活动中使用新的DBManager（）。getAllCities（）。

/**
 * author zaaach on 2016/1/26.
 */
public class DBManager {
    private static final String ASSETS_NAME = "china_cities.db";
    private static final String DB_NAME = "china_cities.db";
    private static final String TABLE_NAME = "city";
    private static final String NAME = "name";
    private static final String PINYIN = "pinyin";
    private static final int BUFFER_SIZE = 1024;
    private String DB_PATH;
    private Context mContext;

//    public static DBManager init(){
//        if (mInstance == null){
//            synchronized (DBManager.class){
//                if (mInstance != null){
//                    mInstance = new DBManager();
//                }
//            }
//        }
//        return mInstance;
//    }

    public DBManager(Context context) {
        this.mContext = context;
        DB_PATH = File.separator + "data"
                + Environment.getDataDirectory().getAbsolutePath() + File.separator
                + context.getPackageName() + File.separator + "databases" + File.separator;
    }

    @SuppressWarnings("ResultOfMethodCallIgnored")
    public void copyDBFile(){
        File dir = new File(DB_PATH);
        if (!dir.exists()){
            dir.mkdirs();
        }
        File dbFile = new File(DB_PATH + DB_NAME);
        if (!dbFile.exists()){
            InputStream is;
            OutputStream os;
            try {
                is = mContext.getResources().getAssets().open(ASSETS_NAME);
                os = new FileOutputStream(dbFile);
                byte[] buffer = new byte[BUFFER_SIZE];
                int length;
                while ((length = is.read(buffer, 0, buffer.length)) > 0){
                    os.write(buffer, 0, length);
                }
                os.flush();
                os.close();
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }


    public List<City> getAllCities(){
        SQLiteDatabase db = SQLiteDatabase.openOrCreateDatabase(DB_PATH + DB_NAME, null);
        Cursor cursor = db.rawQuery("select * from " + TABLE_NAME, null);
        List<City> result = new ArrayList<>();
        City city;
        while (cursor.moveToNext()){
            String name = cursor.getString(cursor.getColumnIndex(NAME));
            String pinyin = cursor.getString(cursor.getColumnIndex(PINYIN));
            city = new City(name, pinyin);
            result.add(city);
        }
        cursor.close();
        db.close();
        Collections.sort(result, new CityComparator());
        return result;
    }

}

如何使用预加载的sqlite数据库[Android Studio]

1 个答案: