My app makes use of SQLiteDatabase to save two arraylists to separate tables.
I have noticed that since implementing the database, whenever it updates the database (involving dropping the tables, recreating them, then populating them with the arraylists) the app briefly freezes and I get the following message in logcat: "I/Choreographer: Skipped 236 frames! The application may be doing too much work on its main thread."
To confirm it was the updating, I removed the code used to update the database. Upon doing that, I no longer got the warning message, and my app didn't freeze.
This is the code inside my custom DB helper, which extends SQLiteOpenHelper, that is used to update the table:
public void insertData(ArrayList<SavedWifiHotspot> hotspots, ArrayList<MarkerOptions> markers) {
Log.d("insert LocationsDB", "Data inserted");
SQLiteDatabase db = this.getWritableDatabase();
ContentValues hotspotValues = new ContentValues();
ContentValues markerValues = new ContentValues();
for(SavedWifiHotspot hotspot : hotspots) {
hotspotValues.put("Ssid", hotspot.getSsid());
hotspotValues.put("Password", hotspot.getPassword());
hotspotValues.put("LocationName", hotspot.getHotspotLoc());
hotspotValues.put("Lat", hotspot.getLatitude());
hotspotValues.put("Lng", hotspot.getLongitude());
db.insert(HOTSPOT_TABLE_NAME, null, hotspotValues);
}
for(MarkerOptions marker : markers) {
markerValues.put("LocationName", marker.getTitle());
markerValues.put("Lat", marker.getPosition().latitude);
markerValues.put("Lng", marker.getPosition().longitude);
db.insert(LOCATION_TABLE_NAME, null, markerValues);
}
}
And this is the code used to clear the tables before they are updated:
public void clearData() {
Log.d("clear LocationsDB", "Tables cleared");
SQLiteDatabase db=this.getWritableDatabase();
String dropHSTable = "DROP TABLE IF EXISTS "
+ HOTSPOT_TABLE_NAME + ";";
String dropLocTable = "DROP TABLE IF EXISTS "
+ LOCATION_TABLE_NAME + ";";
db.execSQL(dropHSTable);
db.execSQL(dropLocTable);
createTables(db);
}
How should I go about updating my database in the background? I've read about threads, should I use a thread to do this?
Edit: This is the error, in reference to my comment.
FATAL EXCEPTION: AsyncTask #5
Process: com1032.cw2.fm00232.fm00232_assignment2, PID: 8830
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:300)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExe
at java.lang.Thread.run(Thread.java:818)cutor$Worker.run(ThreadPoolExecutor.java:587)
Caused by: java.util.ConcurrentModificationException
at java.util.ArrayList$ArrayListIterator.next(ArrayList.java:573)
at com1032.cw2.fm00232.fm00232_assignment2.LocationsDB$3.doInBackground(LocationsDB.java:124)
at at com1032.cw2.fm00232.fm00232_assignment2.LocationsDB$3.doInBackground(LocationsDB.java:119)
at android.os.AsyncTask$2.call(AsyncTask.java:288)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
For reference, line 124 is:
for(MarkerOptions marker: markers[0]) {
And line 119 is:
new AsyncTask<ArrayList<MarkerOptions>, Void, Void>() {
Edit2: Fixed the above problem. My app was invoking the insert data method using empty lists. So I've added .empty check before the insert data method.
An async task sounds like a good idea.
public void insertData(ArrayList<SavedWifiHotspot> hotspots, ArrayList<MarkerOptions> markers) {
Log.d("insert LocationsDB", "Data inserted");
new AsyncTask<ArrayList<SavedWifiHotspot>, Void, Void>() {
@Override
protected Void doInBackground(ArrayList<SavedWifiHotspot>... hotspots) {
ContentValues hotspotValues = new ContentValues();
for(SavedWifiHotspot hotspot : hotspots[0]) {
hotspotValues.put("Ssid", hotspot.getSsid());
hotspotValues.put("Password", hotspot.getPassword());
hotspotValues.put("LocationName", hotspot.getHotspotLoc());
hotspotValues.put("Lat", hotspot.getLatitude());
hotspotValues.put("Lng", hotspot.getLongitude());
db.insert(HOTSPOT_TABLE_NAME, null, hotspotValues);
}
}
}.execute(hotspots);
new AsyncTask<ArrayList<MarkerOptions>, Void, Void>() {
@Override
protected Void doInBackground(ArrayList<MarkerOptions>... options) {
ContentValues hotspotValues = new ContentValues();
for(MarkerOptions marker: options[0]) {
markerValues.put("LocationName", marker.getTitle());
markerValues.put("Lat", marker.getPosition().latitude);
markerValues.put("Lng", marker.getPosition().longitude);
db.insert(LOCATION_TABLE_NAME, null, markerValues);
}
}
}.execute(options);
}
public void clearData() {
Log.d("clear LocationsDB", "Tables cleared");
new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... params) {
SQLiteDatabase db=this.getWritableDatabase();
String dropHSTable = "DROP TABLE IF EXISTS "
+ HOTSPOT_TABLE_NAME + ";";
String dropLocTable = "DROP TABLE IF EXISTS "
+ LOCATION_TABLE_NAME + ";";
db.execSQL(dropHSTable);
db.execSQL(dropLocTable);
createTables(db);
}
}.execute();
}