英文:
How to reference cell data on CellFactory?
问题
我有一个TableView，其中最后一列是一个“操作”列，包含一个自定义的ActionBox对象，其中包含用于多个操作的按钮。为了向这个ActionBox添加行为，我需要传递一个Data对象给它。然而，我不知道如何引用这个对象。
我假设对象的引用在Void item中，所以我尝试将所有出现的Void替换为Data，并使用setGraphic(new ActionBox(item));，但这导致了一个空指针异常，所以我认为这不是正确的方法。那么，在CellFactory上下文中如何引用行的数据呢？
英文:
I have a TableView where the last column is an "Action" column, containing a custom ActionBox object, with buttons for several actions. To add behaviour to this ActionBox, I need to pass a Data object to it. However, I don't know how to reference the object.
class TableViewWithActionColumn() {
@FXML TableColumn<Data, Void> actionColumn;
public TableViewWithActionColumn() {
// Code for loading custom component...
}
@FXML
public void initialize() {
populateActionColumn();
}
private void populateActionColumn() {
Callback<TableColumn<Data, Void>, TableCell<Data, Void>> cellFactory = new Callback<TableColumn<Data, Void>, TableCell<Data, Void>>() {
@Override
public TableCell<Data, Void> call(final TableColumn<Data, Void> param) {
return new TableCell<Data, Void>() {
private final ActionBox actionBox = new ActionBox();
@Override
public void updateItem(Void item, boolean empty) {
super.updateItem(item, empty);
if (empty) {
setGraphic(null);
} else {
setGraphic(actionBox);
}
}
};
}
};
actionColumn.setCellFactory(cellFactory);
}
}
I assumed that the reference to the object was in Void item, so I tried replacing all occurrences of Void with Data, and doing setGraphic(new ActionBox(item));, but this led to a NullPointerException, so I suppose that's not the right way to do it. So, how do I reference row's data in CellFactory context?
答案1
得分: 3
TableCell有一个getTableRow()方法，它可以获取包含该单元格的TableRow的引用。TableRow本身也是一个单元格实现，因此您可以调用它的getItem()方法来获取行所代表的数据。
在上下文中（并且去除您的代码中所有不必要的模板代码）：
private void populateActionColumn() {
actionColumn.setCellFactory(col -> new TableCell<Data, Void>() {
private final ActionBox actionBox = new ActionBox();
@Override
public void updateItem(Void item, boolean empty) {
super.updateItem(item, empty);
if (empty) {
setGraphic(null);
} else {
Data rowData = getTableRow().getItem();
// ... 类似于：actionBox.setData(rowData) ;
setGraphic(actionBox);
}
}
});
}
英文:
TableCell has a getTableRow() method, that gives you a reference to the TableRow that contains the cell. The TableRow is itself a cell implementation, so you can call its getItem() method to get the data represented by the row.
In context (and removing all the unnecessary boilerplate from your code):
private void populateActionColumn() {
actionColumn.setCellFactory(col -> new TableCell<Data, Void>() {
private final ActionBox actionBox = new ActionBox();
@Override
public void updateItem(Void item, boolean empty) {
super.updateItem(item, empty);
if (empty) {
setGraphic(null);
} else {
Data rowData = getTableRow().getItem();
// ... something like: actionBox.setData(rowData) ;
setGraphic(actionBox);
}
}
});
}
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