Wie bekomme ich Daten von der SQLITE-Tabelle

Question

Hallo Ich schreibe diese Anwendung, die Datenbanken verwenden muss, und ich habe in einen Haken geraten. Ich kann nicht scheinen, eine Information von der Datenbank zu erhalten. Ich habe den folgenden Code:

Vertrag Klasse:

public class SettingsContract { 
    private SettingsContract() { 

    } 

    public final class SettingsEntry implements BaseColumns { 
     public static final String TABLE_NAME = "Settings"; 
     public static final String COLUMN_NAME_LAST_REFRESH_DT = "LastRefreshDt"; 
    } 
} 

DbHelper Klasse:

public class SettingsDbHelper extends SQLiteOpenHelper { 
    public static final int DATABASE_VERSION = 1; 
    public static final String DATABASE_NAME = "Database.db"; 

    private static final String SQL_CREATE_ENTRIES = 
     "CREATE TABLE IF NOT EXISTS" + SettingsContract.SettingsEntry.TABLE_NAME + " (" + 
       SettingsContract.SettingsEntry._ID + " INTEGER PRIMARY KEY," + 
       SettingsContract.SettingsEntry.COLUMN_NAME_LAST_REFRESH_DT + " DATE,"; 

    private static final String SQL_DELETE_ENTRIES = 
     "DROP TABLE IF EXISTS " + SettingsContract.SettingsEntry.TABLE_NAME; 

    public SettingsDbHelper(Context context) { 
     super(context, DATABASE_NAME, null, DATABASE_VERSION); 
    } 

    @Override 
    public void onCreate(SQLiteDatabase db) { 
     db.execSQL(SQL_CREATE_ENTRIES); 
    } 

    @Override 
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
     db.execSQL(SQL_DELETE_ENTRIES); 
     onCreate(db); 
    } 

    @Override 
    public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
     onUpgrade(db, oldVersion, newVersion); 
    } 

} 

Und wo ich diesen Code verwenden:

private SettingsDbHelper dbHelper; 

    public SettingsDataSource(Context context) { 
     this.dbHelper = new SettingsDbHelper(context); 
    } 

    public Setting getSettings() { 
     SQLiteDatabase db = this.dbHelper.getReadableDatabase(); 
     Cursor cursor = db.rawQuery("SELECT " + 
SettingsContract.SettingsEntry.COLUMN_NAME_LAST_REFRESH_DT + " FROM " 
+ SettingsContract.SettingsEntry.TABLE_NAME, null); 
... 

Nun, wenn ich rufe die rawQuery Dies ist, was ich in dem Protokoll habe:

04-15 12:18:14.026 2698-2698/com.busridercluj E/SQLiteLog: 
(1) no such table: Settings 

Was fehlt mir hier? Warum wird die Tabelle nicht so erstellt, wie sie sollte?

Answer 1

Ihre Abfrage create table ist falsch, also Tabelle wird nicht erstellt.

private static final String SQL_CREATE_ENTRIES = 
      "CREATE TABLE IF NOT EXISTS " + SettingsContract.SettingsEntry.TABLE_NAME + " (" + 
        SettingsContract.SettingsEntry._ID + " INTEGER PRIMARY KEY," + SettingsContract.SettingsEntry.COLUMN_NAME_LAST_REFRESH_DT + " DATE);"; 



@Override 
    public void onCreate(SQLiteDatabase db) { 
     Log.d("CreateDB", "Create table sql query: " + SQL_CREATE_ENTRIES); 
     db.execSQL(SQL_CREATE_ENTRIES); 
    } 

Protokollausgabe sollte sein: CREATE TABLE IF NOT EXISTS Settings (_id INTEGER PRIMARY KEY, LastRefreshDt DATE);

Answer 2

diese Ihnen helfen könnte ...

MainActivity.class

public class MainActivity extends Activity { 

DatabaseClass dbclass; 
EditText et1,et2,et3; 
Button b1,b2; 

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

    et1 = (EditText) findViewById(R.id.editText1); 
    et2 = (EditText) findViewById(R.id.editText2); 
    et3 = (EditText) findViewById(R.id.editText3); 
    b1 = (Button) findViewById(R.id.button1); 
    b2 = (Button) findViewById(R.id.button2); 
    dbclass = new DatabaseClass(this); 
    onInsert(); 
    onShow(); 

} 

public void onInsert(){ 
    b1.setOnClickListener(new OnClickListener() { 

     @Override 
     public void onClick(View v) { 
          boolean isInserted = dbclass.InsertData(et1.getText().toString(), 
            et2.getText().toString(), 
            et3.getText().toString()); 

          if(isInserted ==true){ 
           Toast.makeText(getApplicationContext(), "data inserted", Toast.LENGTH_LONG).show(); 
          }else 
           Toast.makeText(getApplicationContext(), "data not inserted", Toast.LENGTH_LONG).show(); 

     } 
    }); 
} 

public void onShow(){ 
    b2.setOnClickListener(new OnClickListener() { 

     @Override 
     public void onClick(View v) { 
      Intent in = new Intent(getApplicationContext(),ListActivity.class); 
      startActivity(in); 
      } 
    }); 
} 

}

Helper Klasse

public class DatabaseClass extends SQLiteOpenHelper{ 

public static final String DATABASE_NAME = "Student.db"; 
public static final String TABLE_NAME = "StudentData"; 
public static final String ID= "id"; 
public static final String NAME = "name"; 
public static final String SURNAME = "surname"; 
public static final String MARKS = "marks"; 

public DatabaseClass(Context context) { 
    super(context, TABLE_NAME, null, 1); 
    // TODO Auto-generated constructor stub 
} 

@Override 
public void onCreate(SQLiteDatabase db) { 
    db.execSQL("CREATE TABLE "+TABLE_NAME+"(ID INTEGER PRIMARY KEY AUTOINCREMENT,NAME TEXT,SURNAME TEXT,MARKS INTEGER)"); 

} 

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

public boolean InsertData(String name,String surname,String marks){ 
    SQLiteDatabase db = this.getWritableDatabase(); 
    ContentValues cv = new ContentValues(); 
    cv.put("NAME", name); 
    cv.put("SURNAME", surname); 
    cv.put("MARKS", marks); 
    long result = db.insert(TABLE_NAME, null, cv); 
    if(result==-1){ 
     return false; 
    } 
    return true; 
} 

public Cursor getAllData(){ 
    SQLiteDatabase db = this.getWritableDatabase(); 
    Cursor res = db.rawQuery("SELECT * FROM TABLE NAME", null); 
    return res; 
} 

}

ListActivity.class

public class ListActivity extends Activity { 

ListView l; 
DatabaseClass dba; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.thelist); 
    dba = new DatabaseClass(this); 

    l = (ListView) findViewById(R.id.listView1); 
    ViewAll(); 



} 

public void ViewAll(){ 
    Cursor res = dba.getAllData(); 
    if(res.getCount()==0){ 
     Toast.makeText(this, "no data found", Toast.LENGTH_LONG).show(); 
     return; 
    } 

    /*StringBuffer buffer = new StringBuffer(); 
    while(res.moveToNext()){ 
     buffer.append("ID"+res.getString(0)+"\n"); 
     buffer.append("NAME"+res.getString(1)+"\n"); 
     buffer.append("SURNAME"+res.getString(2)+"\n"); 
     buffer.append("PRICE"+res.getString(3)+"\n"); 
    }*/ 
    //showmessage("DATA",buffer.toString());   
    ArrayAdapter<String> adap = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1,); 
    l.setAdapter(adap); 
} 

}

Adapter.class

public class MyAdapter extends ArrayAdapter<String> { 

private final Context context; 
private final String[] values; 

public MyAdapter(Context context,String[] values) { 
    super(context, R.layout.thelist, values); 
    this.context = context; 
    this.values = values; 
} 

@Override 
public View getView(int position, View convertView, ViewGroup parent) { 
    LayoutInflater inflater = (LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE); 
    View row = inflater.inflate(R.layout.listitems, parent,false); 
    return super.getView(position, convertView, parent); 

    TextView tv1 = (TextView) row.findViewById(R.id.textname); 
    TextView tv2 = (TextView) row.findViewById(R.id.textsurname); 
    TextView tv3 = (TextView) row.findViewById(R.id.textmarks); 
} 

}