Question

我正在尝试通过填充存储在SQLite中的数据来创建帐单模板。我知道有一种方法可以使用ListView来完成此操作。运行此活动时应用程序崩溃。

public class Ticket_generator extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.ticket_table);
    Context context;
    context=this;
    TableHelper datahelper= new TableHelper(context);
   datahelper.insertData("Home foods","Veg Resturant","New Municipal Blog","abc compound","mumbai 400007","01/07/17","COUNTER","BILL NO.-123","Perticulars","Quantity","Rate","gst","06.56AM");
     Cursor cr;
        cr=datahelper.getInformation();
        TextView tv;
        tv=(TextView)findViewById(R.id._s1t1);
        tv.setGravity(Gravity.CENTER);
        tv.setTextSize(16);
        tv.setPadding(5, 5, 5, 5);
        tv.setText(cr.getString(1));
    }

}

这是TableHelper.java

public class TableHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "Ticketdb";
public static final int DATABASE_VERSION = 1;
public static final String TABLE_TICKET = "tblticketdata";
public static final String CREATE_TABLE_TICKET = "CREATE TABLE IF NOT EXISTS " + TABLE_TICKET + "(_id INTEGER PRIMARY KEY AUTOINCREMENT, s1t1 TEXT NULL,s1t2 TEXT NULL,s1t3 TEXT NULL,s1t4 TEXT NULL,s1t5 TEXT NULL,s2t1 TEXT NULL,s2t2 TEXT NULL,s2t3 TEXT NULL, s3t1 TEXT NULL,s3t2 TEXT NULL,s3t3 TEXT NULL,ft1 TEXT NULL,ft2 TEXT NULL)";
public static final String DELETE_TABLE_SERVICES = "DROP TABLE IF EXISTS " + TABLE_TICKET;

public TableHelper(Context context) {

    super(context, DATABASE_NAME, null, DATABASE_VERSION);

}

public void onCreate(SQLiteDatabase db) {

    db.execSQL(CREATE_TABLE_TICKET);

}

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

    db.execSQL(DELETE_TABLE_SERVICES);
    //Create tables again
    onCreate(db);
}

public void insertData(String s1t1, String _s1t2, String _s1t3, String _s1t4, String _s1t5, String _s2t1, String _s2t2,
                       String _s2t3, String _s3t1, String _s3t2, String _s3t3, String _ft1, String _ft2) {

    // Open the database for writing
    SQLiteDatabase db = this.getWritableDatabase();
    // Start the transaction.
    db.beginTransaction();
    ContentValues values;

    try {
        values = new ContentValues();
        values.put("s1t1", s1t1);
        values.put("s1t2", _s1t2);
        values.put("s1t3", _s1t3);
        values.put("s1t4", _s1t4);
        values.put("s1t5", _s1t5);
        values.put("s2t1", _s2t1);
        values.put("s2t2", _s2t3);
        values.put("s2t3", _s2t3);
        values.put("s3t1", _s3t1);
        values.put("s3t2", _s3t2);
        values.put("s3t3", _s3t3);
        values.put("ft1", _ft1);
        values.put("ft2", _ft2);


        // Insert Row
        long i = db.insert(TABLE_TICKET, null, values);
        Log.i("Insert", i + "");
        // Insert into database successfully.
        db.setTransactionSuccessful();

    } catch (SQLiteException e) {
        e.printStackTrace();

    } finally {
        db.endTransaction();
        // End the transaction.
        db.close();
        // Close database
    }

}

public Cursor getInformation() {
    SQLiteDatabase sq = this.getReadableDatabase();
    String[] columns = {"s1t1", "s1t2", "s1t3", "s1t4", "s1t5", "s2t1", "s2t2", "s2t3", "s3t1", "s3t2", "s3t3", "ft1", "ft2"};
    Cursor cr = sq.query(TABLE_TICKET, columns, null, null, null, null, null);
    return cr;
}
}

Answer 1

您需要将光标移动到第一个位置，如下例所示：

public String getFirstResult(){
  String firstResult;
  TableHelper datahelper = new TableHelper(context);
  Cursor cursor = datahelper.getInformation();
  cursor.moveToFirst();
  firstResult = cursor.getString(0);
  return firstResult;
}

TextView没有从sqlite填充数据

1 个答案: