将hashmap与tableview(JavaFX)绑定

Question

我想在JavaFX Tableview中显示HashMap内容。请在下面找到我用来将HashMap内容设置到表列中的代码。我遇到的问题是它只显示了一行。for循环只迭代5次：每次都会获取HashMap的第一个值。

如果忽略return SimpleObjectProperty行，则for循环将迭代HashMap中的所有内容。

final ObservableList<Map> data = FXCollections.observableArrayList();
data.addAll(HASHMAP);
TableColumn<Map.Entry, String> nCol = new TableColumn<Map.Entry, String>("Name");
nCol.setEditable(true);
nCol.setCellValueFactory(new Callback<TableColumn.CellDataFeatures<Entry, String>, ObservableValue<String>>() {
 @Override
 public ObservableValue<String> call(TableColumn.CellDataFeatures<Entry, String> p) {
        Set <String> set=HASHMAP.keySet();
    for (String key:HASHMAP.keySet())
    {
           String key1= key.toString();
           return new SimpleObjectProperty<>(key.toString());
    }
         return null;
        } 
    });
  Table.setItems(data);
  Table.getColumns().setAll(nCol,.........);

Answer 1

1. CellFactory.Callback.call()只创建一个单元格，而不是循环中的所有单元格
2. 从循环中使用return会中断循环执行

看看下一个例子，特别是评论：

public class MapTableView extends Application {
    @Override
    public void start(Stage stage) {
        // sample data
        Map<String, String> map = new HashMap<>();
        map.put("one", "One");
        map.put("two", "Two");
        map.put("three", "Three");

        // use fully detailed type for Map.Entry<String, String> 
        TableColumn<Map.Entry<String, String>, String> column1 = new TableColumn<>("Key");
        column1.setCellValueFactory(new Callback<TableColumn.CellDataFeatures<Map.Entry<String, String>, String>, ObservableValue<String>>() {
            @Override
            public ObservableValue<String> call(TableColumn.CellDataFeatures<Map.Entry<String, String>, String> p) {
                // this callback returns property for just one cell, you can't use a loop here
                // for first column we use key
                return new SimpleStringProperty(p.getValue().getKey());
            }
        });
        TableColumn<Map.Entry<String, String>, String> column2 = new TableColumn<>("Value");
        column2.setCellValueFactory(new Callback<TableColumn.CellDataFeatures<Map.Entry<String, String>, String>, ObservableValue<String>>() {
            @Override
            public ObservableValue<String> call(TableColumn.CellDataFeatures<Map.Entry<String, String>, String> p) {
                // for second column we use value
                return new SimpleStringProperty(p.getValue().getValue());
            }
        });
        ObservableList<Map.Entry<String, String>> items = FXCollections.observableArrayList(map.entrySet());
        final TableView<Map.Entry<String,String>> table = new TableView<>(items);
        table.getColumns().setAll(column1, column2);
        Scene scene = new Scene(table, 400, 400);
        stage.setScene(scene);
        stage.show();
    }
    public static void main(String[] args) {
        launch();
    }
}

Answer 2

Sergey Grinev；我找到了一个解决方案，这个问题的通用解决方案

public class TableCassaController<K,V> extends TableView<Map.Entry<K,V>> implements Initializable {
@FXML   private TableColumn<K, V> column1;
@FXML   private TableColumn<K, V> column2;

public TableCassaController(ObservableMap<K,V> map, String col1Name, String col2Name) {
    System.out.println("Costruttore table");
    TableColumn<Map.Entry<K, V>, K> column1 = new TableColumn<>(col1Name);
    column1.setCellValueFactory(new Callback<TableColumn.CellDataFeatures<Map.Entry<K, V>, K>, ObservableValue<K>>() {
        @Override
        public ObservableValue<K> call(TableColumn.CellDataFeatures<Map.Entry<K, V>, K> p) {
            // this callback returns property for just one cell, you can't use a loop here
            // for first column we use key
            return new SimpleObjectProperty<K>(p.getValue().getKey());
        }
    });
    TableColumn<Map.Entry<K, V>, V> column2 = new TableColumn<>(col2Name);
    column2.setCellValueFactory(new Callback<TableColumn.CellDataFeatures<Map.Entry<K, V>, V>, ObservableValue<V>>() {
        @Override
        public ObservableValue<V> call(TableColumn.CellDataFeatures<Map.Entry<K, V>, V> p) {
            // for second column we use value
            return new SimpleObjectProperty<V>(p.getValue().getValue());
        }
    });
    ObservableList<Map.Entry<K, V>> items = FXCollections.observableArrayList(map.entrySet());
    this.setItems(items);
    this.getColumns().setAll(column1, column2);
}

非常感谢！！！：-）