從DB的ID不顯示

Question

有人可以告訴我，爲什麼一切工作正常，除了在表中顯示ID？數據類型有問題嗎？

有一個代碼，我把數據放到tableView中。

public class TabulkaProdukty { 

    private final FlowPane panelTabulky; 
    public final TableView<Produkty> tabulkaTabulkaProdukty; 
    public ObservableList<Produkty> dataTabulkaProdukty; 
    public static Connection connection; 
    private static Statement statement; 

    public TabulkaProdukty() { 
     panelTabulky = new FlowPane(); 
     tabulkaTabulkaProdukty = new TableView<>(); 
     panelTabulky.getChildren().add(tabulkaTabulkaProdukty); 
     tabulkaTabulkaProdukty.setEditable(true); 
     try { 
      connection = DriverManager.getConnection("jdbc:sqlite:produkty"); 
      statement = connection.createStatement(); 
      statement.executeUpdate("create table if not exists produkty(id INTEGER PRIMARY KEY AUTOINCREMENT UNIQUE, nazev TEXT NOT NULL, popis TEXT NOT NULL, typ TEXT NOT NULL, cena TEXT NOT NULL);"); 
      dataTabulkaProdukty = FXCollections.observableArrayList(); 
      ResultSet rs = connection.createStatement().executeQuery("SELECT * FROM produkty;"); 
      while (rs.next()) { 
       dataTabulkaProdukty.add(new Produkty(rs.getInt("id"), rs.getString("nazev"), rs.getString("popis"), rs.getString("typ"), rs.getString("cena"))); 
      } 

      // VECI V TABULCE 
      TableColumn idCol = new TableColumn("id"); 
      idCol.setMinWidth(50); 
      idCol.setCellValueFactory(
        new PropertyValueFactory<>("id")); 

      TableColumn nazevCol = new TableColumn("Název"); 
      nazevCol.setMinWidth(100); 
      nazevCol.setCellValueFactory(
        new PropertyValueFactory<>("nazev")); 

      TableColumn popisCol = new TableColumn("Popis"); 
      popisCol.setMinWidth(200); 
      popisCol.setCellValueFactory(
        new PropertyValueFactory<>("popis")); 

      TableColumn typCol = new TableColumn("Typ"); 
      typCol.setMinWidth(50); 
      typCol.setCellValueFactory(
        new PropertyValueFactory<>("typ")); 

      TableColumn cenaCol = new TableColumn("Cena"); 
      cenaCol.setMinWidth(50); 
      cenaCol.setCellValueFactory(
        new PropertyValueFactory<>("cena")); 

      tabulkaTabulkaProdukty.setColumnResizePolicy(TableView.CONSTRAINED_RESIZE_POLICY); 
      tabulkaTabulkaProdukty.setItems(null); 
      tabulkaTabulkaProdukty.setItems(dataTabulkaProdukty); 
      tabulkaTabulkaProdukty.getColumns().addAll(idCol, nazevCol, popisCol, typCol, cenaCol); 

     } catch (Exception e) { 
      Alert alert = new Alert(Alert.AlertType.ERROR); 
      alert.setTitle("Error dialog"); 
      alert.setHeaderText("Chyba databáze"); 
      alert.setContentText("Nepovedlo se načíst data z databáze."); 
      alert.showAndWait(); 
     } 

    } 

還有一類導航產品

public class Produkty implements Serializable { 

     private final SimpleIntegerProperty id; 
     private final SimpleStringProperty nazev; 
     private final SimpleStringProperty popis; 
     private final SimpleStringProperty typ; 
     private final SimpleStringProperty cena; 
     public NaMinimum panelNaMinimum; 

     public Produkty(int pID, String pNazev, String pPopis, String pTyp, String pCena) { 
      this.id = new SimpleIntegerProperty(pID); 
      this.nazev = new SimpleStringProperty(pNazev); 
      this.popis = new SimpleStringProperty(pPopis); 
      this.typ = new SimpleStringProperty(pTyp); 
      this.cena = new SimpleStringProperty(pCena); 
     } 

     public int getIDProduktu() {return id.get();} 
     public void setIDProduktu(int pID) {id.set(pID);} 
     public String getNazev() {return nazev.get();} 
     public void setNazev(String pNazev) {nazev.set(pNazev);} 
     public String getPopis() {return popis.get();} 
     public void setPopis(String pPopis) {popis.set(pPopis);} 
     public String getTyp() {return typ.get();} 
     public void setTyp(String pTyp) {typ.set(pTyp);} 
     public String getCena() {return cena.get();} 
     public void setCena(String pCena) {cena.set(pCena);} 

    } 

我真的很感激解決的任何建議。

Answer 1

PropertyValueFactory尋找基於構造函數參數的方法，而不是字段。基於吸氣劑的名稱，參數應該是"IDProduktu"或"iDProduktu"：

idCol.setCellValueFactory(new PropertyValueFactory<>("IDProduktu")); 

注意，沒有財產的getter方法TableView無法觀察到的性質的任何改變。在這種情況下，您可以使用普通字段來獲得相同的效果。爲了觀察變化，您需要提供一種名爲<property>Property的方法，其中<property>是傳遞給構造函數PropertyValueFactory的屬性名稱的佔位符，例如，如果你使用"id"作爲構造參數：

public IntegerProperty idProperty() { 
    return id; 
} 

Answer 2

這將是更好地知道你在做什麼，但我的猜測是，整數值沒有被顯示爲一個字符串，因此不像其他參數一樣。