내가 데이터베이스의 데이터를 업데이트 할 데이터베이스 SQLite는 java.lang.NullPointerException이

Question

를 업데이트 할 수 있지만 라인 sqldb.update에 java.lang.NullPointerException이 있습니다 ... 내가 데이터를 업데이트하는 방법을 검색했습니다하지만 여전히 같은, 제발 나에게 실수 여기

content.java 여기

package ta.ens; 

import android.app.Activity; 
import android.content.ContentValues; 
import android.content.Context; 
import android.content.Intent; 
import android.database.Cursor; 
import android.database.sqlite.SQLiteDatabase; 
import android.graphics.Typeface; 
import android.os.Bundle; 
import android.text.ClipboardManager; 
import android.view.Menu; 
import android.view.MenuInflater; 
import android.view.MenuItem; 
import android.view.View; 
import android.widget.ListView; 
import android.widget.SimpleCursorAdapter; 
import android.widget.TextView; 
import android.widget.Toast; 

public class Content extends Activity { 
    /** Called when the activity is first created. */ 
    //TextView judul,hadits,arti; 
    ListView content; 
    SimpleCursorAdapter adapter; 
    MyDB mydb; 
    Cursor cursor,populer; 
    TextView judul,hadits,arti; 
    SQLiteDatabase sqldb; 
    Context context=this; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.custom_list_hadits);  
     mydb = new MyDB(this); 

     judul = (TextView)findViewById(R.id.textjudul); 
     hadits = (TextView)findViewById(R.id.texthadits); 
     arti = (TextView)findViewById(R.id.textarti); 

     Bundle extras = getIntent().getExtras(); 
     String id = extras.getString("row"); 
     String namajudul = extras.getString("rowjudul");     
     ContentValues cv = new ContentValues(); 
     populer = mydb.getPopularity(id); 
     int jumlah = populer.getCount(); 
     if (jumlah == 0){ 
      cv.put("totalquery", 1); 
      sqldb.update("populer", cv, "_id ?", new String[]{id}); 
     }else { 
      jumlah = jumlah + 1; 
      cv.put("totalquery", jumlah); 
      sqldb.rawQuery("UPDATE populer SET totalquery = "+jumlah+" WHERE _id =" +id, null); 
     } 

     judul.setText(namajudul); 
     hadits.setTypeface(Typeface.createFromAsset(getAssets(), "dejavusans.ttf")); 
     cursor = mydb.getHadits(id); 
     int total = cursor.getCount(); 
     for(int i = 1;i<=total;i++){ 
      String isihadits = ArabicUtilities.reshape(cursor.getString(cursor.getColumnIndex("hadits"))); 
      String isiarti = cursor.getString(cursor.getColumnIndex("arti")); 
      hadits.setText(isihadits); 
      arti.setText(isiarti); 
      cursor.moveToNext(); 
     } 
     hadits.setOnClickListener(new View.OnClickListener() { 

      @Override 
      public void onClick(View arg0) { 
       // TODO Auto-generated method stub 
       ClipboardManager clipboard = (ClipboardManager)getSystemService(CLIPBOARD_SERVICE); 
       clipboard.setText(hadits.getText()); 
       Toast.makeText(context, "Copied to clipboard", Toast.LENGTH_SHORT).show(); 
      } 
     }); 

     arti.setOnClickListener(new View.OnClickListener() { 

      @Override 
      public void onClick(View arg0) { 
       // TODO Auto-generated method stub 
       ClipboardManager clipboard = (ClipboardManager)getSystemService(CLIPBOARD_SERVICE); 
       clipboard.setText(arti.getText()); 
       Toast.makeText(context, "Copied to clipboard", Toast.LENGTH_SHORT).show(); 
      } 
     });   
    } 

    public boolean onCreateOptionsMenu(Menu menu){ 
     MenuInflater inflater = getMenuInflater(); 
     inflater.inflate(R.menu.menuhelp, menu); 
     return true; 

    } 

    public boolean onOptionsItemSelected(MenuItem item){ 
     Intent intent = new Intent(); 
     switch(item.getItemId()){ 
     case R.id.helptema : 
      finish(); 
      intent.setClass(Content.this, Tema.class); 
      startActivity(intent); 
      break; 
     case R.id.searchhelp : 
      finish(); 
      intent.setClass(Content.this, Cari.class); 
      startActivity(intent); 
      break; 
     case R.id.tentanghelp : 
      finish(); 
      intent.setClass(Content.this, Tentang.class); 
      startActivity(intent); 
      break; 
     case R.id.quithelp : 
      finish(); 
      System.exit(0); 
     } 
     return true; 
    } 
} 

의 일부를 보여 여기에 mydb.java

package ta.ens; 

import android.content.Context; 
import android.database.Cursor; 
import android.database.sqlite.SQLiteDatabase; 
import com.readystatesoftware.sqliteasset.SQLiteAssetHelper; 

public class MyDB extends SQLiteAssetHelper{ 

    private static final String DATABASE_NAME = "hadits"; 
    private static final int DATABASE_VERSION = 1; 

    public MyDB(Context context) { 
     super(context, DATABASE_NAME, null, DATABASE_VERSION); 
     // TODO Auto-generated constructor stub 
    } 

    public Cursor getAllTema(){ 
     SQLiteDatabase sqldb = getReadableDatabase(); 

     Cursor c = sqldb.rawQuery("SELECT * FROM tema", null); 

     c.moveToFirst(); 
     return c; 
    } 

    public Cursor getJudul(String id){ 
     SQLiteDatabase sqldb = getReadableDatabase(); 

     Cursor jdl = sqldb.rawQuery("SELECT judul._id,judul.judul FROM judul,tema,temajudul WHERE tema._id = temajudul.idtema AND judul._id = temajudul.idjudul AND tema._id = "+id, null); 
     jdl.moveToFirst(); 
     return jdl; 
    } 

    public Cursor getHadits(String id){ 
     SQLiteDatabase sqldb = getReadableDatabase(); 

     Cursor hadits = sqldb.rawQuery("SELECT hadits.hadits , hadits.arti FROM hadits,judul,judulhadits WHERE judul._id = judulhadits.idjudul AND hadits.rowid = judulhadits.idhadits AND judul._id = "+id, null); 
     hadits.moveToFirst(); 
     return hadits; 
    } 

    public void virtualtabel(){ 
     SQLiteDatabase sqldb = getReadableDatabase(); 
     sqldb.execSQL("INSERT INTO virtualhadits SELECT * FROM hadits"); 
    } 

    public Cursor getAllHadits(){ 
     SQLiteDatabase sqldb = getReadableDatabase(); 
     Cursor allcontent = sqldb.rawQuery("SELECT * FROM virtualhadits", null); 
     return allcontent; 
    } 

    public Cursor getCari(String key){ 
     SQLiteDatabase sqldb = getReadableDatabase();  

     Cursor cari = sqldb.rawQuery("SELECT virtualhadits.rowid AS _id , judul.judul FROM judul,judulhadits,virtualhadits WHERE judul._id = judulhadits.idjudul AND virtualhadits.rowid = judulhadits.idhadits AND virtualhadits MATCH '"+key+"'", 
        null); 
     cari.moveToFirst(); 
     return cari; 
    } 

    public Cursor getPopularity(String id){ 
     SQLiteDatabase sqldb = getReadableDatabase(); 

     Cursor semua = sqldb.rawQuery("SELECT totalquery FROM populer WHERE _id = "+id, null); 
     return semua; 
    } 

    public Cursor getPopularitasJudul(){ 
     SQLiteDatabase sqldb = getReadableDatabase(); 

     Cursor populerjudul = sqldb.rawQuery("SELECT judul._id judul.judul FROM judul,hadits,populer WHERE judul._id = judulhadits.idjudul AND hadits._id = judulhadits.idhadits AND populer._id = hadits._id ORDER BY populer.totalquery DESC", null); 

     return populerjudul; 
    } 
} 

고양이

,536를 기록하다

12-14 13:28:02.821: ERROR/AndroidRuntime(5867): FATAL EXCEPTION: main 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867): java.lang.RuntimeException: Unable to start activity ComponentInfo{ta.ens/ta.ens.Content}: java.lang.NullPointerException 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663) 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679) 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867):  at android.app.ActivityThread.access$2300(ActivityThread.java:125) 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033) 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867):  at android.os.Handler.dispatchMessage(Handler.java:99) 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867):  at android.os.Looper.loop(Looper.java:123) 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867):  at android.app.ActivityThread.main(ActivityThread.java:4627) 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867):  at java.lang.reflect.Method.invokeNative(Native Method) 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867):  at java.lang.reflect.Method.invoke(Method.java:521) 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867):  at dalvik.system.NativeStart.main(Native Method) 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867): Caused by: java.lang.NullPointerException 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867):  at ta.ens.Content.onCreate(Content.java:54) 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627) 
12-14 13:28:02.821: ERROR/AndroidRuntime(5867):  ... 11 more 

Answer 1

변수 SQLiteDatabase sqldb을 초기화하지 않았다고 생각합니다. 당신이 그것을 선언했지만 어디서나 당신이 그것을 초기화 한 것을 보지 못했습니다. mydb 당신이 instert 업데이트 같은 데이터베이스 opertions을 만들기위한 SQLiteAssetHelper 클래스를 확장하는 클래스의 객체이기 때문에 어쩌면 당신이 라인 sqldb.update("populer", cv, "_id ?", new String[]{id});

Answer 2

사용 mydb 대신 업데이트하거나 데이터베이스에서 데이터를 선택하는 sqldb에 NUllPointer을 받고있는 이유가 또는 선택하십시오. 그래서 대신 SQLiteDatabase 예를

if (jumlah == 0){ 
     cv.put("totalquery", 1); 
     mydb.update("populer", cv, "_id ?", new String[]{id}); 
    }else { 
     jumlah = jumlah + 1; 
     cv.put("totalquery", jumlah); 
     mydb.rawQuery("UPDATE populer SET totalquery = 
         "+jumlah+" WHERE _id =" +id, null); 
    } 

Answer 3

이

Better to use: 

if (jumlah == 0){ 
      cv.put("totalquery", 1); 
sqldb=Mydb.getWritableDatabase(); 
      sqldb.execSQL("update populer set _id=id"); 
     }