android - Sqlite数据库只应创建一次

我开发了一个具有c2cm特性的项目。只要服务器上有可用的数据，服务器就会将数据推送到所有安装了此应用程序的设备上（在我的例子中是一个小消息）。
现在我的问题是每次在消息出现的地方创建数据库和表时，
这是我的密码，

 public class MessageHelper extends Activity
    {
        public String str;
        public int sts;
        public Date timeStamp;

        protected void onCreate(Bundle savedInstanceState)
        {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);

            Bundle extras = getIntent().getExtras();
            if (extras != null) {
                this.str = extras.getString("msgg");
                Log.d("C2DM", this.str);
            }

            // Create a ref of SQLite
            SQLiteDatabase db;

            //use tat ref to open or create a table
            db = openOrCreateDatabase( "/data/data/de.vogella.android.c2dm.simpleclient/app_database/file__0/0000000000000001.db", SQLiteDatabase.CREATE_IF_NECESSARY, null);

            try
            {
                //initialsiging a query with all the table fields
                final String CREATE_TABLE_CONTAIN = "CREATE TABLE IF NOT EXISTS tbl_Message4("
                        + "id INTEGER PRIMARY KEY AUTOINCREMENT,"
                        + "msg TEXT not null,"
                        + "msg_time INTEGER not null,"
                        + "msg_status INTEGER not null);";

                //execute the above query
                db.execSQL(CREATE_TABLE_CONTAIN);

                timeStamp = new Date();

                String sql =
                        "INSERT or replace INTO tbl_Message4 (msg,msg_time,msg_status) VALUES('"+this.str+"' ,'"+this.timeStamp+"' , 0)" ;
                db.execSQL(sql);
        }
    }

此外，我还有一个名为MessageReceiver的类，它扩展了BroadcastReceiver；每当消息出现时，都会执行该类，该类将加载MessageHelper.Class
这是MessageReceiver的代码，

public class C2DMMessageReceiver extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        Log.w("C2DM", "Message Receiver called");
        if ("com.google.android.c2dm.intent.RECEIVE".equals(action)) {
            Log.w("C2DM", "Received message");
            final String payload = intent.getStringExtra("payload");
            Log.d("C2DM", "dmControl: payload = " + payload);
            // TODO Send this to my application server to get the real data
            // Lets make something visible to show that we received the message
            createNotification(context, payload);

        }
    }

    public void createNotification(Context context, String payload) {
        NotificationManager notificationManager = (NotificationManager) context
                .getSystemService(Context.NOTIFICATION_SERVICE);
        Notification notification = new Notification(R.drawable.ic_launcher,
                "Message received", System.currentTimeMillis());
        // Hide the notification after its selected
        notification.flags |= Notification.FLAG_AUTO_CANCEL;

        //Intent intent = new Intent(context, MessageReceivedActivity.class);
        //intent.putExtra("payload", payload);

        Intent intent = new Intent(context, MessageHelper.class);
        intent.putExtra("msgg", payload);
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        context.startActivity(intent);
        //PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, intent, 0);
        //notification.setLatestEventInfo(context, "Message", "New message received", pendingIntent);
        //notificationManager.notify(0, notification);

    }

}

我要找的是，第一次安装应用程序时应该创建一个数据库。
提前谢谢你，
泰勒速率

最佳答案

数据库将只创建一次，因为它的名称没有更改。是的，它只会在你的应用程序第一次启动activity messagehelper时创建。