NullPointerExceptionデータベースに行を挿入しようとするとエラーが発生します。私は多くの同様の質問をチェックし、多くのことを試しましたが、何が問題なのかわかりません。
私はNullPointerExceptionここに乗っていますgetDatabase().insert(TABLE_NAME_BUSSES, null, values);
私はこのようなデータベースクラスを使用していますnew MyDatabase(context).addOrUpdate(bus);
このBusクラスは、getter/setter のみを持つ単なるモデル クラスであり、デバッグ中に値をチェックしましたが、null 値にはアクセスしていません。
これが私のデータベースクラスです：
public class MyDatabase implements IDatabaseOperations<Bus>
{
public static final String KEY_BUSSES_NUMBER = "busNumber";
public static final String KEY_BUSSES_SOURCE = "busSource";
public static final String KEY_BUSSES_DESTINATION = "busDestination";
public static final String KEY_BUSSES_ROUTE = "busRoute";
public static final String KEY_BUSSES_ISSTARRED = "busIsStarred";
public static final String KEY_BUSSES_TIMESH = "busTimesH";
public static final String KEY_BUSSES_TIMESC = "busTimesC";
public static final String KEY_BUSSES_TIMESP = "busTimesP";
private static final String DATABASE_NAME = "database";
private static final int DATABASE_VERSION = 1;
private static final String TABLE_NAME_BUSSES = "busses";
private static final String CREATE_SQL = "CREATE TABLE " + TABLE_NAME_BUSSES + " ("
+ KEY_BUSSES_NUMBER + " INTEGER PRIMARY KEY NOT NULL, "
+ KEY_BUSSES_SOURCE + " TEXT NOT NULL, "
+ KEY_BUSSES_DESTINATION + " TEXT NOT NULL, "
+ KEY_BUSSES_ROUTE + " TEXT, "
+ KEY_BUSSES_ISSTARRED + " TEXT NOT NULL, "
+ KEY_BUSSES_TIMESH + " TEXT, "
+ KEY_BUSSES_TIMESC + " TEXT, "
+ KEY_BUSSES_TIMESP + " TEXT);";
private SQLiteDatabase myDatabase;
protected boolean isOpened = false;
private MyDatabaseHelper myHelper;
public static final String LOG_TAG = "Database";
private static class MyDatabaseHelper extends SQLiteOpenHelper
{
public MyDatabaseHelper(Context context)
{
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db)
{
db.execSQL(CREATE_SQL);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME_BUSSES);
onCreate(db);
}
}
public MyDatabase(Context context)
{
myHelper = new MyDatabaseHelper(context);
}
public MyDatabase openDB() throws SQLException
{
isOpened = true;
myDatabase = myHelper.getWritableDatabase();
return this;
}
public void closeDB()
{
isOpened = false;
myHelper.close();
}
public SQLiteDatabase getDatabase()
{
return myDatabase;
}
@Override
public boolean addOrUpdate(Bus entry)
{
/* Result flag */
boolean result = true;
/* If the database is not opened, open it */
if(!isOpened)
{
openDB();
}
/* Set the row */
ContentValues values = new ContentValues();
values.put(KEY_BUSSES_NUMBER, entry.getNumber());
values.put(KEY_BUSSES_SOURCE, entry.getSource());
values.put(KEY_BUSSES_DESTINATION, entry.getDestination());
values.put(KEY_BUSSES_ROUTE, (entry.getRoute() != null ? entry.getRoute() : ""));
values.put(KEY_BUSSES_ISSTARRED, (entry.isStarred() ? 1 : 0));
values.put(KEY_BUSSES_TIMESH, (entry.getTimesH() != null ? new Gson().toJson(entry.getTimesH()) : ""));
values.put(KEY_BUSSES_TIMESC, (entry.getTimesC() != null ? new Gson().toJson(entry.getTimesC()) : ""));
values.put(KEY_BUSSES_TIMESP, (entry.getTimesP() != null ? new Gson().toJson(entry.getTimesP()) : ""));
try
{
/* Check if the entry is already in the database */
int temp = get(entry);
if(temp != -1 && temp == entry.getNumber())
{
/* Updating */
getDatabase().update(TABLE_NAME_BUSSES, values, KEY_BUSSES_NUMBER + "=" + entry.getNumber(), null);
}
else
{
/* Adding */
getDatabase().insert(TABLE_NAME_BUSSES, null, values);
}
}
catch(Exception e)
{
Log.e(LOG_TAG, "Error occurred while adding to/updating database!", e);
result = false;
}
/* If the database is opened, close it */
if(isOpened)
{
closeDB();
}
/* Return the result */
return result;
}
@Override
public int get(Bus entry)
{
/* Resulting number */
int number = -1;
/* If the database is not opened, open it */
if(!isOpened)
{
openDB();
}
/* Column to select which is just number */
String[] columns = new String[]
{
KEY_BUSSES_NUMBER
};
/* Cursor to query the database */
Cursor cursor = getDatabase().query(TABLE_NAME_BUSSES, columns,
KEY_BUSSES_SOURCE + "=" + (entry.getSource() != null ? "\"" + entry.getSource() + "\"" : "NULL") + " AND " +
KEY_BUSSES_DESTINATION + "=" + (entry.getDestination() != null ? "\"" + entry.getDestination() + "\"" : "NULL") + " AND " +
KEY_BUSSES_ROUTE + "=" + (entry.getRoute() != null ? "\"" + entry.getRoute() + "\"" : "NULL") + " AND " +
KEY_BUSSES_ISSTARRED + "=" + (entry.isStarred() ? 1 : 0) + " AND " +
KEY_BUSSES_TIMESH + "=" + (new Gson().toJson(entry.getTimesH()) != null ? "\"" + new Gson().toJson(entry.getTimesH()) + "\"" : "NULL") + " AND " +
KEY_BUSSES_TIMESC + "=" + (new Gson().toJson(entry.getTimesC()) != null ? "\"" + new Gson().toJson(entry.getTimesC()) + "\"" : "NULL") + " AND " +
KEY_BUSSES_TIMESP + "=" + (new Gson().toJson(entry.getTimesP()) != null ? "\"" + new Gson().toJson(entry.getTimesP()) + "\"" : "NULL"),
null, null, null, null);
/* If successfully queried */
if(cursor != null)
{
/* If any match is found */
if(cursor.getCount() > 0)
{
/* Go to the first match */
cursor.moveToFirst();
/* Set the resulting number */
number = cursor.getInt(cursor.getColumnIndex(KEY_BUSSES_NUMBER));
}
}
/* If the database is opened, close it */
if(isOpened)
{
closeDB();
}
/* Return the result */
return number;
}
}