我在滚动窗格内有一个平铺窗格。 tilepane中填充了具有删除或编辑等操作的按钮。删除或编辑按钮后，滚动窗格会自动返回到顶部，这是我不想要的。我希望它保持在当前位置（用户滚动到的位置）。
我尝试获取并设置滚动窗格的vValue。 getvValue获取值并且setter设置它，但是滚动窗格不会响应它并在操作后返回顶部（删除/编辑）。我尝试了这个问题的解决方案：JavaFX ScrollPane setVvalue() not working as intended，但layout（）方法也没有做任何事情。我在这做错了什么？如何让滚动窗保持原状？
编辑：我发现了问题，但仍然不知道如何修复它。显然，在fxml中设置和更改hBox上的可见性会将滚动窗格置于顶部。如果我删除了setVisible方法并运行它，我可以删除项目并且滚动窗格保持在原位。如何解决这个问题？根据要求，我创建了一个Minimal，Complete和Verifiable示例代码。运行它，向下滚动一点，右键单击一个带有名称和价格的按钮，然后单击“删除”。它会向上滚动到顶部。
这是我的代码：
public class Controller {
private static LinkedHashMap<String, BigDecimal> mProductMap = new LinkedHashMap<>();
@FXML private TilePane fieldContainer = new TilePane();
@FXML private ScrollPane scroll;
@FXML private Button deletebtn;
@FXML private Button editbtn;
@FXML private HBox homeBar;
@FXML private HBox actionBar;
@FXML
private void initialize() {
addProduct("Coffee", new BigDecimal("2.00"));
addProduct("Tea", new BigDecimal("2.00"));
addProduct("Cappuccino", new BigDecimal("2.00"));
addProduct("Espresso", new BigDecimal("2.00"));
addProduct("Cooky", new BigDecimal("2.00"));
addProduct("Candy", new BigDecimal("2.00"));
addProduct("Chocobar", new BigDecimal("2.00"));
addProduct("Cola", new BigDecimal("2.00"));
addProduct("Fanta", new BigDecimal("2.00"));
addProduct("Beer", new BigDecimal("2.00"));
addProduct("Salad", new BigDecimal("2.00"));
addProduct("Sandwich", new BigDecimal("2.00"));
addProduct("Water", new BigDecimal("2.00"));
addProduct("Cassis", new BigDecimal("2.00"));
}
// makes the delete and edit buttons appear after selecting a button from the tilepane
private void select(String selectedProduct) {
/*
the setVisible method for the hBoxes in fxml cause the scrollbar to go back to the top
without them, the scrollpane stays where it is.
I tried changing visibility with both setVisible and CSS, but they both cause the problem
I need the actionbar to appear when you select a button (right click on it)
*/
homeBar.setVisible(false);
actionBar.setVisible(true);
EventHandler<ActionEvent> delete = event -> {
deleteProduct(selectedProduct); // deletes an item from a LinkedHashMap
homeBar.setVisible(true);
actionBar.setVisible(false);
};
deletebtn.setOnAction(delete);
// I want the same to happen when the edit handler is used, scrollpane needs to remain its position
EventHandler<ActionEvent> edit = event -> {
editProduct(selectedProduct); // edits an item from a LinkedHashMap
homeBar.setVisible(true);
actionBar.setVisible(false);
};
editbtn.setOnAction(edit);
}
/*
Code below does not cause the problem, but I added it as a reference
*/
private void deleteProduct(String product) {
if (mProductMap.containsKey(product)) {
mProductMap.remove(product);
System.out.printf("%s has been deleted!%n", product);
} else {
System.out.printf("%s does not exist. Please try again.%n", product);
}
addButtons();
}
private void editProduct(String product) {
List<String> indexKeys = new ArrayList<>(mProductMap.keySet());
List<BigDecimal> indexValues = new ArrayList<>(mProductMap.values());
BigDecimal price = mProductMap.get(product); // gets the product's value (the price)
int indexKey = indexKeys.indexOf(product);
int indexValue = indexValues.indexOf(price);
if (mProductMap.containsKey(product)) {
int sizeBefore = mProductMap.size();
addingProduct();
int sizeAfter = mProductMap.size();
if (sizeAfter > sizeBefore) {
indexKeys.remove(product);
indexValues.remove(price);
mProductMap.remove(product);
// Make a new list to get the new entry at the end
List<Map.Entry<String,BigDecimal>> entryList = new ArrayList<>(mProductMap.entrySet());
Map.Entry<String, BigDecimal> lastEntry = entryList.get(entryList.size()-1);
String key = lastEntry.getKey();
BigDecimal value = lastEntry.getValue();
indexKeys.add(indexKey, key);
indexValues.add(indexValue, value);
mProductMap.clear();
// Put the keys and values from the two lists back to the map
for (int i=0; i<indexKeys.size(); i++) {
addProduct(indexKeys.get(i), indexValues.get(i));
}
}
} else {
System.out.printf("%s does not exist. Please try again.%n", product);
}
}
void addProduct(String product, BigDecimal price) {
mProductMap.put(product, price);
addButtons();
}
// Adding buttons to the TilePane fieldContainer in center of BorderPane
// One button per key-value pair of mProductMap
private void addButtons() {
// clears the TilePane to prevent duplicate buttons
fieldContainer.getChildren().clear();
for (Map.Entry<String, BigDecimal> entry : mProductMap.entrySet()) {
StackPane newField = new StackPane();
Button main = new Button();
main.setOnMousePressed(me -> {
if (me.getButton() == MouseButton.SECONDARY) { // = right click
select(entry.getKey());
}
});
main.setText(entry.getKey() + "\n" + entry.getValue());
newField.getChildren().add(main);
fieldContainer.setAlignment(Pos.TOP_LEFT);
fieldContainer.getChildren().add(newField);
}
}
// Popup for adding products to the Map with the + button
@FXML
private void addingProduct(){
Stage newStage = new Stage();
VBox popup = new VBox();
final BooleanProperty firstTime = new SimpleBooleanProperty(true); // Variable to store the focus on stage load
TextField product = new TextField("");
product.setId("product");
product.setPromptText("Enter the item name...");
// code to remove the focus from first textfield on stage load
product.focusedProperty().addListener((observable, oldValue, newValue) -> {
if(newValue && firstTime.get()){
popup.requestFocus(); // Delegate the focus to container
firstTime.setValue(false); // Variable value changed for future references
}
});
TextField price = new TextField("");
price.setId("price");
price.setPromptText("Enter the item price...");
Button submit = new Button("Submit");
Label label = new Label();
label.setId("label");
submit.setOnAction(e -> {
if ( (product.getText() != null && !product.getText().isEmpty() &&
price.getText() != null && !price.getText().isEmpty() ) ) {
addProduct(product.getText(), new BigDecimal(price.getText()) );
newStage.close();
} else {
label.setText("Fill in both fields");
}
});
popup.getChildren().add(product);
popup.getChildren().add(price);
popup.getChildren().add(submit);
popup.getChildren().add(label);
Scene stageScene = new Scene(popup, 300, 200);
newStage.setScene(stageScene);
newStage.showAndWait();
}
}
FXML：
<BorderPane xmlns="http://javafx.com/javafx/8.0.121" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.Controller">
<top>
<StackPane>
<HBox fx:id="homeBar" styleClass="main-bar" visible="true">
<Button StackPane.alignment="BOTTOM_LEFT">Home</Button>
<Button onAction="#addingProduct" StackPane.alignment="BOTTOM_RIGHT">Add a new product</Button>
</HBox>
<HBox fx:id="actionBar" styleClass="main-bar" visible="false">
<Button fx:id="deletebtn" StackPane.alignment="BOTTOM_CENTER">Delete</Button>
<Button fx:id="editbtn" StackPane.alignment="BOTTOM_CENTER">Edit</Button>
<Button onAction="#addingProduct" StackPane.alignment="BOTTOM_RIGHT">Add a new product</Button>
</HBox>
</StackPane>
</top>
<center>
<ScrollPane fx:id="scroll" hbarPolicy="NEVER">
<TilePane fx:id="fieldContainer" prefColumns="2" prefTileHeight="100.0" prefTileWidth="144.0">
</TilePane>
</ScrollPane>
</center>
<bottom>
</bottom>
</BorderPane>
主：
public class Main extends Application {
@Override
public void start(Stage primaryStage) throws Exception{
Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
primaryStage.setScene(new Scene(root, 300, 275));
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
答案 0 :(得分：1)
我自己修复了这个帖子：ScrollPane jumps to top when deleting nodes。
的答案从TilePane中删除按钮后，ScrollPane会找到要关注的下一个节点，默认情况下是该窗格中的第一个节点。通过请求关注TilePane（fieldContainer），ScrollPane保持原位。
我将此代码添加到删除和编辑方法中：
fieldContainer.requestFocus();