커서와 SimpleCursorAdapter

Question

가능한 중복 :
System services not available to Activities before onCreate?

나는 목록보기에 데이터베이스의 값을 반환하려고하지만 오류를 얻고있다. 커서를 사용하여 표에서 데이터를 가져오고 SimpleCursorAdapter를 사용하여 커서를 읽습니다. 이이 작업을 수행하는 방법입니다 : "System Services not available to activites before onCreate()"

이 가

이 사람이 나를 도울 수 :

public void getData(){ 
     String[] columns = new String[] {ModuleDB.KEY_ROWID, 
       ModuleDB.KEY_MODCODE, 
       ModuleDB.KEY_MODNAME, 
       ModuleDB.KEY_LECPRAC, 
       ModuleDB.KEY_DAYS, 
       ModuleDB.KEY_TIMESTART, 
       ModuleDB.KEY_TIMEEND, 
       ModuleDB.KEY_LOCATION, 
       ModuleDB.KEY_INFO}; 
     int[] to = new int[]{R.id.modcode_entry, 
          R.id.modname_entry, 
          R.id.modlecprac_entry, 
          R.id.modday_entry, 
          R.id.modtimestart_entry, 
          R.id.modtimeend_entry, 
          R.id.modlocation_entry, 
          R.id.modaddinfo_entry}; 

     Cursor curs = myDatabase.query(ModuleDB.DB_TABLE, columns, null, null, null, null, null); 
     if (curs != null) 
      curs.moveToFirst(); 

     SimpleCursorAdapter dataSource = new SimpleCursorAdapter(ModuleDataSource.this, R.layout.list_entry, curs, columns, to); 
     this.setListAdapter(dataSource); 

     // Make sure to close the cursor 
     curs.close(); 
     } 

이 메소드는 예외를 일으키는? 나는 커서 및 cursoradapters에 대한 좋은 자습서를 찾을 수 없습니다 난 정말 완전히

편집 손실 오전 :

이 도움이 될 수 있습니다.

MainActivity.java

public class MainActivity extends Activity { 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     ModuleDataSource dbinfo = new ModuleDataSource(this); 
     dbinfo.open(); 
     dbinfo.getData(); 
     dbinfo.close(); 
    } 

ModuleDataSource.java

public class ModuleDataSource extends ListActivity{ 

    private SQLiteDatabase myDatabase; 
    private ModuleDB myhelper; 

    public ModuleDataSource(Context context){ 
     myhelper = new ModuleDB(context); 
    } 

    public void open() throws SQLException { //Open the database for writing 
     myDatabase = myhelper.getWritableDatabase(); 
    } 

    public void close(){ //Close the database 
     myhelper.close(); 
    } 

    public void getData(){ 
     String[] columns = new String[] {ModuleDB.KEY_ROWID, 
       ModuleDB.KEY_MODCODE, 
       ModuleDB.KEY_MODNAME, 
       ModuleDB.KEY_LECPRAC, 
       ModuleDB.KEY_DAYS, 
       ModuleDB.KEY_TIMESTART, 
       ModuleDB.KEY_TIMEEND, 
       ModuleDB.KEY_LOCATION, 
       ModuleDB.KEY_INFO}; 
     int[] to = new int[]{R.id.modcode_entry, 
          R.id.modname_entry, 
          R.id.modlecprac_entry, 
          R.id.modday_entry, 
          R.id.modtimestart_entry, 
          R.id.modtimeend_entry, 
          R.id.modlocation_entry, 
          R.id.modaddinfo_entry}; 

     Cursor curs = myDatabase.query(ModuleDB.DB_TABLE, columns, null, null, null, null, null); 
     startManagingCursor(curs); 

     if (curs != null) 
      curs.moveToFirst(); 

     SimpleCursorAdapter dataSource = new SimpleCursorAdapter(ModuleDataSource.this, R.layout.list_entry, curs, columns, to); 
     setListAdapter(dataSource); 

     } 
} 

EDIT2 : 로그 캣

11-06 23:24:07.885: D/AndroidRuntime(887): Shutting down VM 
11-06 23:24:07.885: W/dalvikvm(887): threadid=1: thread exiting with uncaught exception (group=0x4001d800) 
11-06 23:24:07.895: E/AndroidRuntime(887): FATAL EXCEPTION: main 
11-06 23:24:07.895: E/AndroidRuntime(887): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.adoherty.assignment3/com.adoherty.assignment3.MainActivity}: 
              java.lang.IllegalStateException: System services not available to Activities before onCreate() 
11-06 23:24:07.895: E/AndroidRuntime(887): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663) 
11-06 23:24:07.895: E/AndroidRuntime(887): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679) 
11-06 23:24:07.895: E/AndroidRuntime(887): at android.app.ActivityThread.access$2300(ActivityThread.java:125) 
11-06 23:24:07.895: E/AndroidRuntime(887): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033) 
11-06 23:24:07.895: E/AndroidRuntime(887): at android.os.Handler.dispatchMessage(Handler.java:99) 
11-06 23:24:07.895: E/AndroidRuntime(887): at android.os.Looper.loop(Looper.java:123) 
11-06 23:24:07.895: E/AndroidRuntime(887): at android.app.ActivityThread.main(ActivityThread.java:4627) 
11-06 23:24:07.895: E/AndroidRuntime(887): at java.lang.reflect.Method.invokeNative(Native Method) 
11-06 23:24:07.895: E/AndroidRuntime(887): at java.lang.reflect.Method.invoke(Method.java:521) 
11-06 23:24:07.895: E/AndroidRuntime(887): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
11-06 23:24:07.895: E/AndroidRuntime(887): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
11-06 23:24:07.895: E/AndroidRuntime(887): at dalvik.system.NativeStart.main(Native Method) 
11-06 23:24:07.895: E/AndroidRuntime(887): Caused by: java.lang.IllegalStateException: System services not available to Activities before onCreate() 
11-06 23:24:07.895: E/AndroidRuntime(887): at android.app.Activity.getSystemService(Activity.java:3526) 
11-06 23:24:07.895: E/AndroidRuntime(887): at android.widget.ResourceCursorAdapter.<init>(ResourceCursorAdapter.java:49) 
11-06 23:24:07.895: E/AndroidRuntime(887): at android.widget.SimpleCursorAdapter.<init>(SimpleCursorAdapter.java:84) 
11-06 23:24:07.895: E/AndroidRuntime(887): at com.adoherty.assignment3.ModuleDataSource.getData(ModuleDataSource.java:74) 
11-06 23:24:07.895: E/AndroidRuntime(887): at com.adoherty.assignment3.MainActivity.onCreate(MainActivity.java:17) 
11-06 23:24:07.895: E/AndroidRuntime(887): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
11-06 23:24:07.895: E/AndroidRuntime(887): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627) 
11-06 23:24:07.895: E/AndroidRuntime(887): ... 11 more 

Answer 1

ModuleDataSource extends ListActivity .. 당신이 당신의 활동에서 그의 인스턴스를 생성하는 일반적으로 시스템 호출을 자동으로 백그라운드에서 자동으로 수행하려고합니다. 당신이 개체로 ListActivity를 인스턴스화하려고하기 때문에, 정상적인 활동 과정은

당신은 당신의 주요 활동에 ListActivity에서 당신이 무엇을 이동해야하고 주요 활동 ListActivity을 ... 일이되지

이런 식으로 뭔가 : 유사

public class MainActivity extends ListActivity { 

    private SQLiteDatabase myDatabase; 
    private ModuleDB myhelper; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     myhelper = new ModuleDB(this); 
     open(); 
     getData(); 
     close(); 
    } 

    public void open() throws SQLException { //Open the database for writing 
     myDatabase = myhelper.getWritableDatabase(); 
    } 

    public void close(){ //Close the database 
     myhelper.close(); 
    } 

    public void getData(){ 
     String[] columns = new String[] {ModuleDB.KEY_ROWID, 
       ModuleDB.KEY_MODCODE, 
       ModuleDB.KEY_MODNAME, 
       ModuleDB.KEY_LECPRAC, 
       ModuleDB.KEY_DAYS, 
       ModuleDB.KEY_TIMESTART, 
       ModuleDB.KEY_TIMEEND, 
       ModuleDB.KEY_LOCATION, 
       ModuleDB.KEY_INFO}; 
     int[] to = new int[]{R.id.modcode_entry, 
          R.id.modname_entry, 
          R.id.modlecprac_entry, 
          R.id.modday_entry, 
          R.id.modtimestart_entry, 
          R.id.modtimeend_entry, 
          R.id.modlocation_entry, 
          R.id.modaddinfo_entry}; 

     Cursor curs = myDatabase.query(ModuleDB.DB_TABLE, columns, null, null, null, null, null); 
     startManagingCursor(curs); 

     SimpleCursorAdapter dataSource = new SimpleCursorAdapter(ModuleDataSource.this, R.layout.list_entry, curs, columns, to); 
     setListAdapter(dataSource); 

     } 
} 

Answer 2

당신은 당신의 활동 생성자에서 일을하고, 즉 우 uld는 onCreate()에서 대신 수행됩니다.

그것은 아마 것과 같은 문제입니다 .. 당신은 당신 ListActivity가 그

같은 객체로 활동을 인스턴스화 할 수 없습니다 System services not available to Activities before onCreate?