通过ListView获取ListCell [英] Get ListCell via ListView
问题描述
我有一个 ListView ，带有我自己的 ListCell< MyObject> 实现。通过网络信号，我收到应该更改的ListCell的索引。
I have a ListView with my own ListCell<MyObject> implementation. Via a network signal, I receive an index of my ListCell that should be changed.
超过 listView.getItems（）。get（index）; 访问模型没有问题，但是我想使用收到的索引对listCell进行布局更改，并使用索引+ 1对ListCell进行布局更改;
Over listView.getItems().get(index); there is no problem to access the model, but I want to make a layout change to the listCell with the received index and a layout change to the ListCell with the index+1;
如何通过ListView访问ListCell？
How can I access the ListCell via the ListView?
我搜索这样的方法：
listView.getListCell(index);
推荐答案
不幸的是现在没有API来获取List Cell通过索引或获取ListView的所有子项（listcells）。一种解决方案是，在MyObject类中定义一个新的StringProperty specialIndicator。
Unfortunately right now there is no API to get List Cell by index or to get All children's(listcells) for ListView. One solution can be, define a new StringProperty specialIndicator in your MyObject class.
class MyObject {
....//u r properties
private StringProperty specialIndicator;
当你从网络信号中获得索引时，设置object的这个specialIndicator属性并对ListView执行forcerefresh
When ever you get index from network signal set this specialIndicator property of object and do forcerefresh of ListView
public void onReceivedNetWorkSignalIndex() {
listView.getItems().get(indexFromService).setSpecialIndicator("selected");
listView.getItems().get(indexFromService+1).setSpecialIndicator("selectedplusone");
//force refresh listview (it will trigger cellFactory again so that you can manipulate layout)
listView.setItems(null);
listView.setItems(allObjects);
}
因为你已经有自定义对象ListView，我假设你已经有自定义cellFactory（如果不是你必须创建一个），修改你的自定义单元工厂来处理这个特殊的指标
As you already have custom Object ListView , i am assuming you already have custom cellFactory (if not you have to create one ) ,Modify your custom cell factory to handle this special Indicators
listView.setCellFactory(new Callback<ListView<MyObject>, ListCell<MyObject>>() {
@Override
public ListCell<MyObject> call(ListView<MyObject> myObjectListView) {
ListCell<MyObject> cell = new ListCell<MyObject>(){
@Override
protected void updateItem(MyObject myObject, boolean b) {
super.updateItem(myObject, b);
if(myObject != null) {
setText(myObject.getName());
if("selected".equalsIgnoreCase(myObject.getSpecialIndicator())) {
System.out.println("Setting new CSS/graphics for index retun from service." + myObject.getName());
} else if("selectedplusone".equalsIgnoreCase(myObject.getSpecialIndicator())) {
System.out.println("Setting new CSS/Graphics for index+1 returned from service" + myObject.getName());
}
myObject.setSpecialIndicator(""); // reset it back to empty
}
}
};
return cell;
}
});
以下是整个示例应用程序，您可以查看它（如果上述说明不清楚） ）。
Here is the whole sample Application ,you can look into it (in case the above explanation is not clear).
public class ListViewTest extends Application {
@Override
public void start(Stage stage) throws Exception {
VBox root = new VBox();
final ObservableList<MyObject> allObjects = FXCollections.observableArrayList(new MyObject("object0"), new MyObject("object1"),new MyObject("object2"),new MyObject("object3"),new MyObject("object4"));
final ListView<MyObject> listView = new ListView<>(allObjects);
listView.setCellFactory(new Callback<ListView<MyObject>, ListCell<MyObject>>() {
@Override
public ListCell<MyObject> call(ListView<MyObject> myObjectListView) {
ListCell<MyObject> cell = new ListCell<MyObject>(){
@Override
protected void updateItem(MyObject myObject, boolean b) {
super.updateItem(myObject, b);
if(myObject != null) {
setText(myObject.getName());
if("selected".equalsIgnoreCase(myObject.getSpecialIndicator())) {
System.out.println("Setting new CSS/graphics for index retun from service." + myObject.getName());
setText("I am selected Index from Service");
} else if("selectedplusone".equalsIgnoreCase(myObject.getSpecialIndicator())) {
System.out.println("Setting new CSS/Graphics for index+1 returned from service" + myObject.getName());
setText("I am selected Index +1 from Service");
}
myObject.setSpecialIndicator(""); // reset it back to empty
}
}
};
return cell;
}
});
Button serviceIndex2 = new Button("ServiceIndex2");
serviceIndex2.setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent actionEvent) {
int indexFromService =2;
listView.getItems().get(indexFromService).setSpecialIndicator("selected");
listView.getItems().get(indexFromService+1).setSpecialIndicator("selectedplusone");
listView.setItems(null);
listView.setItems(allObjects);
}
});
root.getChildren().addAll(listView,serviceIndex2);
Scene scene = new Scene(root,500,500);
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch(args);
}
class MyObject {
private StringProperty name;
private StringProperty specialIndicator;
MyObject(String name) {
this.name = new SimpleStringProperty(name);
this.specialIndicator = new SimpleStringProperty();
}
public String getName() {
return name.get();
}
public StringProperty nameProperty() {
return name;
}
public void setName(String name) {
this.name.set(name);
}
public String getSpecialIndicator() {
return specialIndicator.get();
}
public StringProperty specialIndicatorProperty() {
return specialIndicator;
}
public void setSpecialIndicator(String specialIndicator) {
this.specialIndicator.set(specialIndicator);
}
}
}
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