This doesn’t answer the original question How can I properly re-open room db after I close it? However, moving everything to the original database file is what you want to do, then you don’t have to close the database in the first place. You can instead force a checkpoint using the wal_checkpoint pragma. Query the … Read more
Use a transaction to insert all the rows — NOT one row per transaction. SQLiteDatabase db = … db.beginTransaction(); try { // do ALL your inserts here db.setTransactionSuccessful() } finally { db.endTransaction(); } EDIT public void add_cities(List<Cities> list) { SQLiteDatabase db = this.getWritableDatabase(); db.beginTransaction(); try { ContentValues values = new ContentValues(); for (Cities city : … Read more
First you have to specify the path of the sdcard. You can do that by creating a string like this: public static final String DATABASE_FILE_PATH = “/sdcard”; But for you should call Environment.getExternalStorageDirectory() to get the root path to the SD card and use that to create the database. After that you create the database … Read more
You can’t replace database in onUpgrade() because in this method the database is already in use. You have to do it before the database is open, like in a constructor of your DatabaseHelper. As you can’t use onUpgrade(), you have to manage database versioning by yourself. Using SharedPreferences is a good way for it. You … Read more
According to Android documentation, Resources.getSystem() only provides system-level resources, not application-level ones (like the resources inside your strings.xml file). http://developer.android.com/reference/android/content/res/Resources.html#getSystem() Try using the application’s context if you really want to retrieve your strings this way, or take my suggestion in the comment to your question.
What’s the correct way of handling database upgrades of a live app, so the user doesn’t lose his data? Do you have to check all possible (old) versions in the onUpgrade() method and execute different alter table statements based on that version? By and large, yes. A common approach to this is to do pair-wise … Read more
Sqlite helper class helps us to manage database creation and version management. SQLiteOpenHelper takes care of all database management activities. To use it, 1.Override onCreate(), onUpgrade() methods of SQLiteOpenHelper. Optionally override onOpen() method. 2.Use this subclass to create either a readable or writable database and use the SQLiteDatabase’s four API methods insert(), execSQL(), update(), delete() … Read more
SQLiteOpenHelper onCreate() and onUpgrade() callbacks are invoked when the database is actually opened, for example by a call to getWritableDatabase(). The database is not opened when the database helper object itself is created. SQLiteOpenHelper versions the database files. The version number is the int argument passed to the constructor. In the database file, the version … Read more