基于数据类信息

Question

我对编辑数据这个可编辑的JavaFX表自动创建的TableView列：

public class DataTable { 

    public void initTable(Stage primaryStage, Group root, Scene scene) { 

     tableView.setEditable(true); 
     Callback<TableColumn, TableCell> cellFactory = 
       new Callback<TableColumn, TableCell>() { 
      @Override 
      public TableCell call(TableColumn p) { 
       return new EditingCell(); 
      } 
     }; 

     TableColumn columnMonth = new TableColumn("Month"); 
     columnMonth.setCellValueFactory(
       new PropertyValueFactory<Record, String>("fieldMonth")); 

     TableColumn columnValue = new TableColumn("Value"); 
     columnValue.setCellValueFactory(
       new PropertyValueFactory<Record, Double>("fieldValue")); 

     //--- Add for Editable Cell of Value field, in Double 
     columnValue.setCellFactory(cellFactory); 
     columnValue.setOnEditCommit(
       new EventHandler<TableColumn.CellEditEvent<Record, Double>>() { 
      @Override 
      public void handle(TableColumn.CellEditEvent<Record, Double> t) { 
       ((Record) t.getTableView().getItems().get(
         t.getTablePosition().getRow())).setFieldValue(t.getNewValue()); 
      } 
     }); 
     //--- 

     tableView.setItems(dataList); 
     tableView.getColumns().addAll(columnMonth, columnValue); 

     VBox vBox = new VBox(); 
     vBox.setSpacing(10); 
     vBox.getChildren().add(tableView); 
     vBox.setLayoutX(410); 
     vBox.setLayoutY(34); 

     root.getChildren().add(vBox); 


    } 

    public class Record { 

     private SimpleStringProperty fieldMonth; 
     private SimpleDoubleProperty fieldValue; 

     Record(String fMonth, double fValue) { 
      this.fieldMonth = new SimpleStringProperty(fMonth); 
      this.fieldValue = new SimpleDoubleProperty(fValue); 
     } 

     public String getFieldMonth() { 
      return fieldMonth.get(); 
     } 

     public double getFieldValue() { 
      return fieldValue.get(); 
     } 

     public void setFieldMonth(String fMonth) { 
      fieldMonth.set(fMonth); 
     } 

     public void setFieldValue(Double fValue) { 
      fieldValue.set(fValue); 
     } 
    } 
    private TableView<Record> tableView = new TableView<>(); 
    private ObservableList<Record> dataList = 
      FXCollections.observableArrayList(
      new Record("January", 100), 
      new Record("February", 200), 
      new Record("March", 50), 
      new Record("April", 75), 
      new Record("May", 110), 
      new Record("June", 300), 
      new Record("July", 111), 
      new Record("August", 30), 
      new Record("September", 75), 
      new Record("October", 55), 
      new Record("November", 225), 
      new Record("December", 99)); 

    class EditingCell extends TableCell<Record, Double> { 

     private TextField textField; 

     public EditingCell() { 
     } 

     @Override 
     public void startEdit() { 
      super.startEdit(); 

      if (textField == null) { 
       createTextField(); 
      } 

      setGraphic(textField); 
      setContentDisplay(ContentDisplay.GRAPHIC_ONLY); 
      textField.selectAll(); 
     } 

     @Override 
     public void cancelEdit() { 
      super.cancelEdit(); 

      setText(String.valueOf(getItem())); 
      setContentDisplay(ContentDisplay.TEXT_ONLY); 
     } 

     @Override 
     public void updateItem(Double item, boolean empty) { 
      super.updateItem(item, empty); 

      if (empty) { 
       setText(null); 
       setGraphic(null); 
      } else { 
       if (isEditing()) { 
        if (textField != null) { 
         textField.setText(getString()); 
        } 
        setGraphic(textField); 
        setContentDisplay(ContentDisplay.GRAPHIC_ONLY); 
       } else { 
        setText(getString()); 
        setContentDisplay(ContentDisplay.TEXT_ONLY); 
       } 
      } 
     } 

     private void createTextField() { 
      textField = new TextField(getString()); 
      textField.setMinWidth(this.getWidth() - this.getGraphicTextGap() * 2); 
      textField.setOnKeyPressed(new EventHandler<KeyEvent>() { 
       @Override 
       public void handle(KeyEvent t) { 
        if (t.getCode() == KeyCode.ENTER) { 
         commitEdit(Double.parseDouble(textField.getText())); 
        } else if (t.getCode() == KeyCode.ESCAPE) { 
         cancelEdit(); 
        } 
       } 
      }); 
     } 

     private String getString() { 
      return getItem() == null ? "" : getItem().toString(); 
     } 
    } 
} 

我要创建的小程序，可以显示从数据库表中的数据和编辑表。当我点击一个表时我遇到了这个问题，我必须从JPA对象中生成动态表视图，所以我每次都有一个表，但具有不同的列。我能以某种方式在每次使用来自JPA的数据生成表格时根据情况自动更新列吗？

Answer 1

您可以使用反射来实现这一点。例如，分析你的数据类的方法，并为每一个与Property结束创建列：

public class SmartTableView extends Application { 

    private void populateColumns(Class clazz, TableView table) { 
     for (Method method : clazz.getMethods()) { 
      String name = method.getName(); 
      if (name.endsWith("Property")) { 
       String propName = name.replace("Property", ""); 

       TableColumn column = new TableColumn(propName); 
       column.setCellValueFactory(new PropertyValueFactory<>(propName)); 
       table.getColumns().add(column); 
      } 
     } 
    } 

    @Override 
    public void start(Stage primaryStage) { 
     final ObservableList<Person> data = FXCollections.observableArrayList(
       new Person("Jacob", "Smith", "jacob.smith@example.com"), 
       new Person("Isabella", "Dow", "isabella.dow@example.com"), 
       new Person("Ethan", "Williams", "ethan.williams@example.com"), 
       new Person("Emma", "Jones", "emma.jones@example.com"), 
       new Person("Michael", "Brown", "michael.brown@example.com")); 

     TableView table = new TableView(data); 
     populateColumns(Person.class, table); 

     Scene scene = new Scene(table, 300, 250); 
     primaryStage.setTitle("Hello"); 
     primaryStage.setScene(scene); 
     primaryStage.show(); 
    } 

    public static void main(String[] args) { 
     launch(args); 
    } 

    public static class Person { 

     private final SimpleStringProperty firstName; 
     private final SimpleStringProperty lastName; 
     private final SimpleStringProperty email; 

     private Person(String fName, String lName, String email) { 
      this.firstName = new SimpleStringProperty(fName); 
      this.lastName = new SimpleStringProperty(lName); 
      this.email = new SimpleStringProperty(email); 
     } 

     public String getFirstName() { 
      return firstName.get(); 
     } 

     public void setFirstName(String fName) { 
      firstName.set(fName); 
     } 

     public StringProperty firstNameProperty() { 
      return firstName; 
     } 

     public String getLastName() { 
      return lastName.get(); 
     } 

     public void setLastName(String fName) { 
      lastName.set(fName); 
     } 

     public StringProperty lastNameProperty() { 
      return lastName; 
     } 

     public String getEmail() { 
      return email.get(); 
     } 

     public void setEmail(String fName) { 
      email.set(fName); 
     } 

     public StringProperty emailProperty() { 
      return lastName; 
     } 
    } 
} 

要调整表列