当我在关闭数据库后尝试调用它时,我的自定义SQLiteOpenHelper类中的一个方法会引发“尝试重新打开已关闭的对象”错误。我在我的MainActivity的onPause中关闭数据库,然后在调用数据库方法之前确保它们是否打开。SQLiteDatabase在AsyncTask中打开数据库(Android)
这是数据库方法的代码,它在AsyncTask中。
public void insertData(ArrayList<SavedWifiHotspot> hotspots, ArrayList<MarkerOptions> markers) {
Log.d("insert LocationsDB", "Data inserted");
final SQLiteDatabase db = this.getWritableDatabase();
new AsyncTask<ArrayList<SavedWifiHotspot>, Void, Void>() {
@Override
protected Void doInBackground(ArrayList<SavedWifiHotspot>... hotspots) {
Log.d("insert LocationsDB", "Hotspot inserted");
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);
}
return null;
}
}.execute(hotspots);
new AsyncTask<ArrayList<MarkerOptions>, Void, Void>() {
@Override
protected Void doInBackground(ArrayList<MarkerOptions>... markers) {
ContentValues markerValues = new ContentValues();
for(MarkerOptions marker: markers[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);
}
return null;
}
}.execute(markers);
}
这是用来调用该方法的代码:
public void updateLocDB() {
if(!db.isOpen()) {
db = locDB.getReadableDatabase();
}
if(!wifiHotspots.isEmpty() && !markers.isEmpty()) {
locDB.clearData();
locDB.insertData(wifiHotspots, markers);
}
}
logcat的输出:
FATAL EXCEPTION: AsyncTask #1
Process: com1032.cw2.fm00232.fm00232_assignment2, PID: 368
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$1.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
Caused by: java.lang.IllegalStateException: attempt to re-open an
already-closed object: SQLiteDatabase:/data/data/com1032.cw2.fm00232.fm00232_assignment2/databases/locationsDB
at android.database.sqlite.SQLiteClosable.acquireReference(SQLiteClosable.java:55)
at android.database.sqlite.SQLiteDatabase.executeSql(SQLiteDatabase.java:1659)
at android.database.sqlite.SQLiteDatabase.execSQL(SQLiteDatabase.java:1605)
at com1032.cw2.fm00232.fm00232_assignment2.LocationsDB$1.doInBackground(LocationsDB.java:89)
at com1032.cw2.fm00232.fm00232_assignment2.LocationsDB$1.doInBackground(LocationsDB.java:75)
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)
我一直在寻找了几个小时,并不能发现什么这有助于我解决这个问题。任何帮助,将不胜感激。
clearData代码:
public void clearData() {
Log.d("clear LocationsDB", "Tables cleared");
db = this.getReadableDatabase();
new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... params) {
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);
return null;
}
}.execute();
}
我想你不是在clearData()方法中关闭你的数据库,然后在insertData()方法中再次打开它。 –
数据库未在clearData()中关闭。在我的onPause方法中,我调用updateLocDB(),然后关闭数据库。 – Isengrim
看到答案,希望这会帮助你。 –