java - android sqlite没有这样的表错误(代码1)

Question

当我按下列出数据库项目的按钮时，出现此错误。我的错在哪里？ (当我查看 DDMS 时，我在设备存储中看到 exDB 文件？？)

VT_baglanti3 类

public class VT_baglanti3 extends SQLiteOpenHelper {

  // DataBase oluşturma
  private static final String VT="exDB"; // veri tabanı adi
  private static final Integer SURUM=1;  // veri tabanı sürümü

  public VT_baglanti3(Context c) {
    super(c, VT, null, SURUM); // yukarıda tanımlanan değişkenleri parametre olarak verdik.

  }

  @Override
  public void onCreate(SQLiteDatabase db) {
    // tablo ekleme
      db.execSQL("CREATE TABLE IF NOT EXISTS EMP_TABLE(_id integer primary key,E_NAME text,E_AGE text,E_DEPT text)");
  }

  @Override
  public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {

  }
}

F_tarif_yaz 类

public class F_tarif_yaz extends Fragment {

  private View root;

  Context con;

  private VT_baglanti3 db; 
  private TextView txt;
  Button bt;

  @Override
  public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    root = inflater.inflate(R.layout.tarif_yaz, container, false);
    con=inflater.getContext();

    db=new VT_baglanti3(con);
    txt=(TextView)root.findViewById(R.id.txt);
    bt=(Button)root.findViewById(R.id.bt);


    bt.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Listele2();
        }
    });

    return root;
  }

  private void Listele2(){
    String sutunlar[]={"E_NAME","E_AGE","E_DEPT"};
    SQLiteDatabase sldb2=db.getReadableDatabase(); 

    Cursor cursor1=sldb2.query("exDB",sutunlar,null,null,null,null,null);

    String tumbilgi="";

    while (cursor1.moveToNext()){ 
        String adbilgi=cursor1.getString(cursor1.getColumnIndex("E_NAME")); 

       String soyadbilgi=cursor1.getString(cursor1.getColumnIndex("E_AGE"));
        String nobilgi=cursor1.getString(cursor1.getColumnIndex("E_DEPT"));  

        tumbilgi += adbilgi + " " + soyadbilgi + " " + nobilgi + " " + "\n"; 

    }
    txt.setText(tumbilgi);
  }
}

错误日志

/com.yeni E/AndroidRuntime: FATAL EXCEPTION: main
                                                    Process: com.yeni, PID: 1442
                                                    android.database.sqlite.SQLiteException: no such table: exDB (code 1): , while compiling: SELECT E_NAME, E_AGE, E_DEPT FROM exDB
                                                        at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
                                                        at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:889)
                                                        at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:500)
                                                        at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
                                                        at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
                                                        at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
                                                        at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44)
                                                        at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1314)
                                                        at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1161)
                                                        at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1032)
                                                        at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1200)
                                                        at com.yeni.F_tarif_yaz.Listele2(F_tarif_yaz.java:50)
                                                        at com.yeni.F_tarif_yaz.access$000(F_tarif_yaz.java:15)
                                                        at com.yeni.F_tarif_yaz$1.onClick(F_tarif_yaz.java:39)
                                                        at android.view.View.performClick(View.java:4438)
                                                        at android.view.View$PerformClick.run(View.java:18422)
                                                        at android.os.Handler.handleCallback(Handler.java:733)
                                                        at android.os.Handler.dispatchMessage(Handler.java:95)
                                                        at android.os.Looper.loop(Looper.java:136)
                                                        at android.app.ActivityThread.main(ActivityThread.java:5001)
                                                        at java.lang.reflect.Method.invokeNative(Native Method)
                                                        at java.lang.reflect.Method.invoke(Method.java:515)
                                                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
                                                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
                                                        at dalvik.system.NativeStart.main(Native Method)

错误行

com.yeni.F_tarif_yaz.Listele2(F_tarif_yaz.java:50)   at                        Cursor cursor1=sldb2.query("exDB",sutunlar,null,null,null,null,null);

Answer 1

DDMS i see exDB file in device storage

您的数据库中没有名为 exDB 的TABLE。 SQLite 数据库的文件名完全无关。

参见:https://sqlite.org/lang_createtable.html