首先,这里所有类似的帖子都没有帮助。
在 AsyncTask 中,我检查应用程序启动是否是第一次启动,这意味着我检查是否有数据库。我想通过从表中查询来做到这一点。这是正在执行的:
@Override
public List<Entity> loadAll(Entity markerEntity)
{
Log.i(TAG, "trying to load all entities of type " + markerEntity.getTable());
List<Entity> results = new LinkedList<Entity>();
SQLiteDatabase db = defaultSQLiteOpenHelper.getWritableDatabase();
Cursor cursor = db.query(markerEntity.getTable(), markerEntity.getAllColumns(), null, null, null, null, null);
cursor.moveToFirst();
while (!cursor.isAfterLast())
{
Entity result = markerEntity.createNewInstance(cursor);
results.add(result);
cursor.moveToNext();
}
db.close();
return results;
}
IllegalArgumentException: database not open的崩溃发生在这一行。
SQLiteDatabase db = defaultSQLiteOpenHelper.getWritableDatabase();
它恰好发生在方法(见下文)createAllTables 上。
文档说:
创建和/或打开将用于读取和写入的数据库。第一次调用时,将打开数据库并调用 onCreate(SQLiteDatabase)、onUpgrade(SQLiteDatabase, int, int) 和/或 onOpen(SQLiteDatabase)。
在我看来,它应该执行我的 DefaultSQLiteOpenhelper 并创建所有数据库表,但它不这样做:
public class DefaultSQLiteOpenHelper extends SQLiteOpenHelper implements ISQLiteOpenHelper
{
private static final String TAG = DefaultSQLiteOpenHelper.class.getSimpleName();
private static final String DATABASE_NAME = "MY_DATABASE";
private static final int DATABASE_VERSION = 1;
@Inject
public DefaultSQLiteOpenHelper(Context context)
{
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
//is called by the framework if the database doesn't exist
@Override
public void onCreate(SQLiteDatabase db)
{
Log.i(TAG, "no database found. Generating new database...");
createAllTables(db);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
Log.w(TAG, "Upgrading database from version " + oldVersion + " to " + newVersion);
// db.execSQL("DROP TABLE IF EXISTS " + TABLE_COMMENTS); ///TODO when upgrade
// onCreate(db);
}
//The order must not be changed because sqlite doesn't allow
//table modification. That means one cannot add constraints afterwards
//which results in creating tables in a specific order
private final void createAllTables(SQLiteDatabase db)
{
db.beginTransaction();
//create lookups at first
db.execSQL(TableFactory.createUsage());
db.execSQL(TableFactory.createLanguage());
db.execSQL(TableFactory.createAccount());
db.execSQL(TableFactory.createPreferences());
db.execSQL(TableFactory.createLanguageUsageRel());
db.execSQL(TableFactory.createPantry());
db.execSQL(TableFactory.createProduct());
//populate lookups
db.execSQL(DataFactory.populateUsage());
db.execSQL(DataFactory.populateLanguage());
db.setTransactionSuccessful();
db.endTransaction();
db.close();
}
}
问题是,它为什么不打开数据库?文档说它必须。我不接受任何肮脏的解决方法作为手动打开数据库之类的解决方案。我的代码到底有什么问题?我不敢相信这是Android中的错误。
这是堆栈跟踪:
05-27 17:25:50.370:I/DefaultSQLiteOpenHelper(719):未找到数据库。正在生成新数据库... 05-27 17:25:50.400: W/dalvikvm(719): threadid=10: 线程以未捕获的异常退出 (group=0x40015560) 05-27 17:25:50.400: E/AndroidRuntime(719 ): 致命异常:AsyncTask
1 05-27 17:25:50.400: E/AndroidRuntime(719): java.lang.RuntimeException: 执行时发生错误
doInBackground() 05-27 17:25:50.400: E/AndroidRuntime(719): 在 android.os.AsyncTask$3.done(AsyncTask.java:200) 05-27 17:25:50.400: E/AndroidRuntime(719) : 在 java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274) 05-27 17:25:50.400: E/AndroidRuntime(719): 在 java.util.concurrent.FutureTask.setException(FutureTask.java :125) 05-27 17:25:50.400: E/AndroidRuntime(719): 在 java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308) 05-27 17:25:50.400: E/AndroidRuntime (719): 在 java.util.concurrent.FutureTask.run(FutureTask.java:138) 05-27 17:25:50.400: E/AndroidRuntime(719): 在 java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor. java:1088) 05-27 17:25:50.400: E/AndroidRuntime(719): 在 java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581) 05-27 17:25:50.400: E/AndroidRuntime(719): 在 java.lang.Thread.run(Thread.java:1019) 05-27 17:25:50.400: E/AndroidRuntime(719): 引起作者:java.lang.IllegalStateException:数据库未打开 05-27 17:25:50.400:E/AndroidRuntime(719):在 android.database.sqlite.SQLiteDatabase.endTransaction(SQLiteDatabase.java:555) 05-27 17:25 :50.400: E/AndroidRuntime(719): 在 android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:137) 05-27 17:25:50.400: E/AndroidRuntime(719): 在 com.mydomain.android。 base.persistence.PersistenceManager.loadAll(PersistenceManager.java:58) 05-27 17:25:50.400: E/AndroidRuntime(719): at com.mydomain.android.base.main.StartupTask.isFirstStartAfterInstallation(StartupTask.java:107 ) 05-27 17:25:50.400: E/AndroidRuntime(719): at com.mydomain.android.base.main。StartupTask.doInBackground(StartupTask.java:52) 05-27 17:25:50.400: E/AndroidRuntime(719): at com.mydomain.android.base.main.StartupTask.doInBackground(StartupTask.java:18) 05-27 17:25:50.400: E/AndroidRuntime(719): 在 android.os.AsyncTask$2.call(AsyncTask.java:185) 05-27 17:25:50.400: E/AndroidRuntime(719): 在 java.util。 concurrent.FutureTask$Sync.innerRun(FutureTask.java:306) 05-27 17:25:50.400: E/AndroidRuntime(719): ... 4 更多306) 05-27 17:25:50.400: E/AndroidRuntime(719): ... 4 更多306) 05-27 17:25:50.400: E/AndroidRuntime(719): ... 4 更多