Question

我有一个引用应用程序，它的资产文件夹中有一个名为successquotes的SQLite数据库。

当我启动应用程序时，我在successquotes（资产中的sqllite本地数据库）中加载了一些数据现在我在数据库中添加了更多数据但是当我尝试更新应用程序时，它没有显示我最近在本地数据库中添加的额外数据。

我该怎么做才能显示新的更新数据？我的databasehelper类如下所示。

有人可以告诉我需要做些什么改变吗？

public class DataBaseHandler extends SQLiteOpenHelper {

    // The Android's default system path of your application database.
    private static String DB_PATH;

    private static String DB_NAME = "SuccessQuotes";

    private SQLiteDatabase myDataBase;

    private final Context myContext;


    /**
     * Constructor Takes and keeps a reference of the passed context in order to
     * access to the application assets and resources.
     * 
     * @param context
     */
    public DataBaseHandler(Context context) {

        super(context, DB_NAME, null, 1);
        this.myContext = context;
        DB_PATH = context.getDatabasePath(DB_NAME).toString();
        Log.e("path", DB_PATH);
    }

    // ==============================================================================

    /**
     * Creates a empty database on the system and rewrites it with your own
     * database.
     * */
    public void createDataBase() throws IOException {

        boolean dbExist = checkDataBase();

        if (dbExist) {
            // do nothing - database already exist
        } else {

            // By calling this method and empty database will be created into
            // the default system path
            // of your application so we are gonna be able to overwrite that
            // database with our database.
            this.getReadableDatabase();

            try {

                copyDataBase();

            } catch (IOException e) {

                throw new Error("Error copying database");

            }
        }

    }

    // ==============================================================================

    /**
     * Check if the database already exist to avoid re-copying the file each
     * time you open the application.
     * 
     * @return true if it exists, false if it doesn't
     */
    private boolean checkDataBase() {

        SQLiteDatabase checkDB = null;

        try {
            String myPath = DB_PATH;
            checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

        } catch (SQLiteException e) {

            // database does't exist yet.

        }

        if (checkDB != null) {

            checkDB.close();

        }

        return checkDB != null ? true : false;
    }

    // ==============================================================================

    /**
     * Copies your database from your local assets-folder to the just created
     * empty database in the system folder, from where it can be accessed and
     * handled. This is done by transfering bytestream.
     * */
    private void copyDataBase() throws IOException {

        // Open your local db as the input stream
        InputStream myInput = myContext.getAssets().open(DB_NAME);

        // Path to the just created empty db
        String outFileName = DB_PATH;

        // Open the empty db as the output stream
        OutputStream myOutput = new FileOutputStream(outFileName);

        // transfer bytes from the inputfile to the outputfile
        byte[] buffer = new byte[1024];
        int length;
        while ((length = myInput.read(buffer)) > 0) {
            myOutput.write(buffer, 0, length);
        }

        // Close the streams
        myOutput.flush();
        myOutput.close();
        myInput.close();

    }

    // ==============================================================================

    public void openDataBase() throws SQLException {

        // Open the database
        String myPath = DB_PATH;
        myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

    }

    // ==============================================================================

    @Override
    public synchronized void close() {

        if (myDataBase != null)
            myDataBase.close();

        super.close();

    }

    // ==============================================================================

    @Override
    public void onCreate(SQLiteDatabase db) {

    }

    // ==============================================================================

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion){



    }
}

Answer 1

我建议你使用BroadcastReceiver。数据库更改/填充新数据后，您可以从数据库处理程序发送广播事件：

Intent localIntent = new Intent();
localIntent.addFlags(Intent.FLAG_INCLUDE_STOPPED_PACKAGES);
localIntent.setAction("some_action_string");

在您希望收到通知的活动中，您注册了BroadcastReceiver：

public class DatabaseUpdateReceiver extends BroadcastReceiver {

        @Override
        public void onReceive(Context context, Intent intent) {
            //do your update here
        }
    }

在您的活动中（在onCreate中）注册此广播接收器以接收从您的数据库处理程序发送的更新：

DatabaseUpdateReceiver receiver = new DatabaseUpdateReceiver();
IntentFilter intentFilter = new IntentFilter("some_action_string");
intentFilter.addCategory(Intent.CATEGORY_DEFAULT);
registerReceiver(receiver , intentFilter);

升级SQLite数据库

1 个答案: