Android SQLite - > StackOverflowError

我是Android的初學者。我正在開發一個沒有任何驗證的簡單登錄頁面的應用程序。點擊登錄按鈕後，下一頁必須在微調器中顯示錶格。當我運行我的應用程序時，我得到一個StackOverflowError異常。請幫我解決。Android SQLite - > StackOverflowError

display.java

import android.os.Bundle; 
import android.support.v7.app.AppCompatActivity; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.widget.AdapterView; 
import android.widget.ArrayAdapter; 
import android.widget.Spinner; 
import android.widget.Toast; 

import java.util.ArrayList; 

public class display extends AppCompatActivity { 

    Spinner spinner; 
    private MyDBHandler helper = new MyDBHandler(null, null, null, 1); 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_display); 

     spinner = (Spinner) findViewById(R.id.mySpinner); 
     ArrayList<String> arrTblNames; 
     arrTblNames = helper.gettablename(); 

     ArrayAdapter<String> arrayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_dropdown_item_1line, arrTblNames); 

     arrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); 
     spinner.setAdapter(arrayAdapter); 

     spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { 
      @Override 
      public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { 
       Toast.makeText(getBaseContext(), parent.getItemIdAtPosition(position) + "", Toast.LENGTH_LONG).show(); 
      } 

      @Override 
      public void onNothingSelected(AdapterView<?> parent) { 

      } 
     }); 

    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is 
     present. 
       getMenuInflater().inflate(R.menu.menu_main, menu); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     // Handle action bar item clicks here. The action bar will 
     // automatically handle clicks on the Home/Up button, so long 
     // as you specify a parent activity in AndroidManifest.xml. 
     int id = item.getItemId(); 

     //noinspection SimplifiableIfStatement 
     if(id == R.id.action_settings) { 
      return true; 
     } 

     return super.onOptionsItemSelected(item); 
    } 
}

MyDBHandler

import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteOpenHelper; 
import android.database.Cursor; 
import android.content.Context; 

import java.util.ArrayList; 

public class MyDBHandler extends SQLiteOpenHelper { 
    ArrayList<String> arrTblName = new ArrayList<>(); 
    private MyDBHandler dbhelper = new MyDBHandler(null, null, null, 1); 
    private SQLiteDatabase dbt = dbhelper.getWritableDatabase(); 

    private static final int DATABASE_VERSION = 1; 
    private static final String DATABASE_NAME = "productDB.db"; 
    public static final String TABLE_PRODUCTS = "products"; 
    public static final String TABLE_PRODUCTSTWO = "productstwo"; 
    public static final String COLUMN_ID = "_id"; 
    public static final String COLUMN_PRODUCTNAME = "productname"; 
    public static final String COLUMN_IDTWO = "_id"; 
    public static final String COLUMN_PRODUCTNAMETWO = "productname"; 

    //We need to pass database information along to superclass 
    public MyDBHandler(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) { 
     super(context, DATABASE_NAME, factory, DATABASE_VERSION); 
    } 

    @Override 
    public void onCreate(SQLiteDatabase db) { 
     String query = "CREATE TABLE " + TABLE_PRODUCTS + "(" + 
       COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + 
       COLUMN_PRODUCTNAME + " TEXT " + 
       ");"; 
     String querytwo = "CREATE TABLE " + TABLE_PRODUCTSTWO + "(" + 
       COLUMN_IDTWO + " INTEGER PRIMARY KEY AUTOINCREMENT, " + 
       COLUMN_PRODUCTNAMETWO + " TEXT " + 
       ");"; 
     db.execSQL(query); 
     db.execSQL(querytwo); 
    } 

    public ArrayList<String> gettablename() { 
     Cursor c = dbt.rawQuery("SELECT name FROM sqlite_master WHERE type='table'", null); 

     if(c.moveToFirst()) { 
      while(!c.isAfterLast()) { 
       arrTblName.add(c.getString(c.getColumnIndex("name"))); 
       c.moveToNext(); 
      } 
     } 
     c.close(); 

     return arrTblName; 
    } 

    @Override 
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
     db.execSQL("DROP TABLE IF EXISTS " + TABLE_PRODUCTS); 
     onCreate(db); 
    } 
}

錯誤

E/AndroidRuntime: FATAL EXCEPTION: main 
       java.lang.StackOverflowError 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:0) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
        at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.java:20) 
       at com.example.arjun.intentlogin.MyDBHandler.<init>(MyDBHandler.jav

d/dalvikvm：GC_CONCURRENT釋放604K，27％的遊離3233K/4423K，暫停12ms + 1ms，共計80次MS 從目標VM斷開，地址： '本地主機：8600'，運輸： '插座'

來源

2016-11-14 arjun

嘿,,,, StackOverFlowError的原因是過深或無限遞歸。用適當的日誌檢查你的代碼。 – GvSharma

哪一行做堆棧轉儲指向？ –

因爲'private MyDBHandler dbhelper = new MyDBHandler（null，null，null，1）;'當您使用public MyDBHandler（Context context，String name，SQLiteDatabase.CursorFactory factory，int version）創建一個對象時調用{super ，DATABASE_NAME，工廠，DATABASE_VERSION）; }'它調用變量init調用構造函數調用變量init調用構造函數 – EpicPandaForce

public class MyDBHandler extends SQLiteOpenHelper { 
    private MyDBHandler dbhelper = new MyDBHandler(null, null, null, 1);

從MyDBHandler類刪除這一領域。類的每個實例都會創建同一個類的新實例，並且此遞歸將繼續，直到堆棧耗盡。

來源

2016-11-14 08:22:23 laalto

變化display類是這樣的：

public class display extends AppCompatActivity { 

    Spinner spinner; 
    private MyDBHandler helper = null; //HERE 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_display); 

     helper = new MyDBHandler(this, "dbName", null, 1); //HERE 

...

來源

2016-11-14 08:28:00 javadaskari

我得到一個error here ==> helper = new MyDBHandler（this，「dbName」，null，1）; // HERE – arjun

上MyDBHandler更改您的構造函數：在DataBaseHelper的

private final Context myContext;

public MyDBHandler(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); this.myContext = context; }

實例上的顯示類：

DataBaseHelper myDbHelpers = new DataBaseHelper(context);

來源

2016-11-14 08:47:32 Simangele

我已經做了這些更正，現在我得到NullPointerException .. at com.example.arjun.intentlogin.MyDBHandler.gettablename（MyDBHandler.java:53）在這一行==> [Cursor c = dbt。 rawQuery（「SELECT name FROM sqlite_master WHERE type ='table'」，null）; ] at com.example.arjun.intentlogin.display.onCreate（display。java：29） at this line ==> [arrTblNames = helper.gettablename（）; ] – arjun

Android SQLite - > StackOverflowError

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