Einfügen und Abrufen von Daten in SQLite

Question

Ich habe Schwierigkeiten beim Einfügen von Daten in meine SQLite-Datenbank. Wenn ich meine addData() Methode anrufe, stürzt meine App ab. Ich rufe meine addData Methode (die in MainActivity ist) von meiner GameView Klasse innerhalb meiner onTouchEvent Methode. Ich muss meine turns Ganzzahl in die COLUMN_SCORES Spalte in meiner Datenbank einfügen. Schätze jede Hilfe!

DatabaseHelper.java:

public class DatabaseHelper extends SQLiteOpenHelper { 

    public static final String DATABASE_NAME = "scores.db"; 
    public static final String TABLE_NAME = "scores_table"; 
    public static final String COLUMN_ID = "ID"; 
    public static final String COLUMN_SCORE = "SCORE"; 

    public DatabaseHelper(Context context) { 
     super(context, DATABASE_NAME, null, 1); 
    } 

    @Override 
    public void onCreate(SQLiteDatabase db) { 
     db.execSQL("create table " + TABLE_NAME +" (ID INTEGER PRIMARY KEY AUTOINCREMENT, SCORE 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 score) { 
     SQLiteDatabase db = this.getWritableDatabase(); 
     ContentValues contentValues = new ContentValues(); 
     contentValues.put(COLUMN_SCORE, score); 
     long result = db.insert(TABLE_NAME, null, contentValues); 

     if(result == -1) { 
      return false; 
     } 
     else { 
      return true; 
     } 
    } 

    public Cursor getAllData() { 
     SQLiteDatabase db = this.getWritableDatabase(); 
     Cursor res = db.rawQuery("select * from " + TABLE_NAME, null); 
     return res; 
    } 

    public boolean updateData(String id, String score) { 
     SQLiteDatabase db = this.getWritableDatabase(); 
     ContentValues contentValues = new ContentValues(); 
     contentValues.put(COLUMN_ID, id); 
     contentValues.put(COLUMN_SCORE, score); 
     db.update(TABLE_NAME, contentValues, "ID = ?", new String[] { id }); 
     return true; 
    } 

    public Integer deleteData(String id) { 
     SQLiteDatabase db = this.getWritableDatabase(); 
     return db.delete(TABLE_NAME, "ID = ?", new String[] { id }); 
    } 
} 

GameView.java:

public class GameView extends View { 

    int mcolumns = 5; 
    int mrows = 5; 
    private NetwalkGrid mGame = new NetwalkGrid(mcolumns, mrows); 
    private GestureDetector mGestureDetector; 
    Random rand = new Random(); 
    int sizeSqX; 
    int sizeSqY; 
    int sizeSq; 

    public static int turns;   
    Paint bgPaint; 

    public GameView(Context context) { 
     super(context); 
     init(); 
    } 

    private void init() { 

    bgPaint = new Paint(Paint.ANTI_ALIAS_FLAG); 
     bgPaint.setStyle(Paint.Style.FILL); 
     bgPaint.setColor(0xff0000ff); 
    mGame.gridCopy(); 

     for (int col = 0; col < mGame.getColumns(); col++) { 
      for (int row = 0; row < mGame.getRows(); row++) { 

       int num = rand.nextInt(3) + 1; 

       for (int turns = 1; turns < num; turns++) { 
        mGame.rotateRight(col, row); 
       } 
      } 
     } 
    } 

    @Override 
    protected void onDraw(Canvas canvas) { 

     canvas.drawColor(Color.BLACK); 

     sizeSqX = getWidth()/mcolumns; 
     sizeSqY = getHeight()/mrows; 

     if (sizeSqX < sizeSqY) { 
      sizeSq = sizeSqX; 
     } 
     else { 
      sizeSq = sizeSqY; 
     } 

     Bitmap b = BitmapFactory.decodeResource(getResources(), R.drawable.placeholder); 
     //Bitmap s = BitmapFactory.decodeResource(getResources(), R.drawable.straight); 
     //Bitmap dl = BitmapFactory.decodeResource(getResources(), R.drawable.downleft); 
     int cellContent; 

     //square = get width/col 
     int square = 140; 
     for (int col = 0; col < mGame.getColumns(); col++) { 
      for (int row = 0; row < mGame.getRows(); row++) { 

       cellContent = mGame.getGridElem(col,row); 
       if (cellContent == 1) { 
        b = BitmapFactory.decodeResource(getResources(), R.drawable.up_down); // Image for down position 
        if (cellContent == 65 && mGame.checkWin()) { 
         b = BitmapFactory.decodeResource(getResources(), R.drawable.up_down_connected); 
        } 
       } 
       else if (cellContent == 2) { 
        b = BitmapFactory.decodeResource(getResources(), R.drawable.left_right); // Right position 
        if (mGame.checkWin()) { 
         b = BitmapFactory.decodeResource(getResources(), R.drawable.left_right_connected); 
        } 
       } 
       else if (cellContent == 3) { 
        b = BitmapFactory.decodeResource(getResources(), R.drawable.right_down); // Down right position WORKS 
        if (mGame.checkWin()) { 
         b = BitmapFactory.decodeResource(getResources(), R.drawable.right_down_connected); 
        } 

       else { 
        b = BitmapFactory.decodeResource(getResources(), R.drawable.placeholder2); // 
       } 

       canvas.drawBitmap(b, null,new Rect(col * sizeSq, row * sizeSq,col*sizeSq+sizeSq, row*sizeSq+sizeSq), null); 

       //Paint paint = new Paint(); 
       //paint.setColor(Color.WHITE); 
       // paint.setStyle(Paint.Style.FILL); 

       TextPaint tp = new TextPaint(); 
       tp.setColor(Color.GREEN); 
       tp.setTextSize(70); 
       tp.setTypeface(Typeface.create("Courier", Typeface.BOLD)); 
       canvas.drawText("Moves: " + String.valueOf(turns), 10, 1180, tp); 
       canvas.drawText("High score: ", 10, 1280, tp); 

      } 
     } 
    } 

    //SoundPoolPlayer sound = new SoundPoolPlayer(getContext()); 

    @Override 
    public boolean onTouchEvent(MotionEvent event) { 
     //boolean eventConsumed = mGestureDetector.onTouchEvent(event); 
     //GameView mGameView = new GameView(getApplicationContext()); 

     //if (eventConsumed) { 
      int x = (int) event.getX(); 
      int y = (int) event.getY(); 

      int column = getColTouched(event.getX()); 
      int row = getRowTouched(event.getY()); 

     try { 
      mGame.rotateRight(column, row); 
      System.out.println(mcolumns); 

      turns++; 
      MainActivity main = new MainActivity(); 
      //main.setTurns(); 
      main.addData(); 
      //main.getData(); 

      mGame.checkWin(); 

      if (mGame.checkWin()) { 
       System.out.println("check win works"); 
       invalidate(); 

       //main.setTurns(); 
       //main.AddData(); 

      } 
      invalidate(); 

     } 
     catch (ArrayIndexOutOfBoundsException err) { 
      System.out.println("User has pressed outside game grid - exception caught"); 
     } 

     //sound.playShortResource(R.raw.click); 
     // sound.release(); 

     return super.onTouchEvent(event); 

    } 

    public int getColTouched(float x) { 
     return (int) (x/sizeSq); 
    } 

    public int getRowTouched(float y) { 
     return (int) (y/sizeSq); 
    } 

    public int getCols() { 
     return mcolumns; 
    } 

    public void setColRow(int columns, int rows) { 
     this.mcolumns = columns; 
     this.mrows = rows; 
    } 

    public int getTurns() { 
     return turns; 
    } 

} 

MainActivity.java:

public class MainActivity erweitert AppCompatActivity {

private GestureDetector mGestureDetector; 
    private ImageView imageView; 

    private RadioGroup radioGroup; 

    private int mcolumns; 
    private int mrows; 

    DatabaseHelper myDb; 

    String test = "test data"; 
    int turns; 

    static Context appcon; 

    String highScore; 

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

     appcon = this; 
     myDb = new DatabaseHelper(this); 

    } 

    public void runGame(View view){ 

     Intent intent = new Intent(this, GameViewActivity.class); 

     startActivity(intent); 
    } 

    public void runInstructions(View view) { 

     Intent intent = new Intent(this, InstructionsActivity.class); 

     startActivity(intent); 
    } 


    public void setTurns() { 
     //GameView mGameView = new GameView(getApplicationContext()); 
     this.turns = GameView.turns; 
     System.out.println("Turns: " + Integer.toString(turns)); 
    } 

    public void addData() { 

     boolean isInserted = myDb.insertData(test); 
     if(isInserted == true) { 
      System.out.println("Data inserted"); 
     } 
     else { 
      System.out.println("Data NOT inserted"); 
     } 
    } 

    public void getData() { 
     Cursor res = myDb.getAllData(); 
     StringBuffer buffer = new StringBuffer(); 
     while(res.moveToNext()) { 
      buffer.append(res.getString(1)); 
     } 
     System.out.println(buffer.toString()); 
    } 

} 

Answer 1

In Ihrem onTouchEvent in der GameView Klasse, anstatt eine neue Instanz von MainActivity zu erstellen, von der ich vermute, dass die Fehlerursache vorliegt, können Sie die insertData Methode der DatabaseHelper Klasse direkt aufrufen. z.B. anstelle der Verwendung: -

 MainActivity main = new MainActivity(); 
     //main.setTurns(); 
     main.addData(); 
     //main.getData(); 

Versuchen

 DatabaseHelper mydb = new DatabaseHelper(this); 
     mydb.insertData("test");