从 ListView 拖放到 TreeView
我只想将一个项目从我的 ListView
拖放到我的 TreeView
中的特定位置.我知道如何处理 DragEvent
s.但是我怎样才能得到我的 treeView 的放置位置呢?位置"是指在哪个树视图项目上下降(从该树视图项目获取参考)".
I just want to drag and drop an item from my ListView
to a specific position in my TreeView
. I know how to handle DragEvent
s. But how can I get the dropped position of my treeView? With "position" I mean "on which treeview-item dropped (get reference from this treeview-item)".
package main;
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.Event;
import javafx.event.EventHandler;
import javafx.event.EventType;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.input.DragEvent;
import javafx.scene.input.MouseDragEvent;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;
import javafx.util.Callback;
public class Program extends Application {
String buffer = "";
public static void main(String args[]) {
launch(args);
}
@Override
public void start(Stage primaryStage) throws Exception {
primaryStage.setTitle("Tree View Sample");
HBox box = new HBox();
//ListView
ListView<String> list = new ListView<String>();
ObservableList<String> items = FXCollections.observableArrayList(
"Single", "Double", "Suite", "Family App");
list.setItems(items);
list.setOnDragDetected(new EventHandler<MouseEvent>() {
@Override
public void handle(MouseEvent event) {
System.out.println("Drag something from ListView");
}
});
//TreeView
TreeItem<String> rootItem = new TreeItem<String>("Inbox");
rootItem.setExpanded(true);
for (int i = 1; i < 6; i++) {
TreeItem<String> item = new TreeItem<String>("Message" + i);
rootItem.getChildren().add(item);
}
TreeView<String> treeView = new TreeView<String>(rootItem);
treeView.setEditable(true);
treeView.setCellFactory(new Callback<TreeView<String>, TreeCell<String>>() {
@Override
public TreeCell<String> call(TreeView<String> stringTreeView) {
TreeCell<String> treeCell = new TreeCell<String>() {
protected void updateItem(String item, boolean empty) {
super.updateItem(item, empty);
if (item != null) {
setText(item);
}
}
};
treeCell.setOnDragDetected(new EventHandler<MouseEvent>() {
@Override
public void handle(MouseEvent mouseEvent) {
System.out.println("Drag: " + treeCell.getItem());
}
});
treeCell.setOnDragDropped(new EventHandler<DragEvent>() {
public void handle(DragEvent event) {
//THIS METHOD DOESN'T WORK (It doesn't called, when i drag something from listview to treeview)
System.out.println("Dropped something");
event.setDropCompleted(true);
event.consume();
}
});
return treeCell;
}
});
box.getChildren().addAll(list,treeView);
//Create Scene
Scene scene = new Scene(box);
//Add Scene to Stage..
primaryStage.setScene(scene);
primaryStage.show();
}
}
除了 setOnDragDetected 处理程序外,没有任何工作.为什么?
示例我正在尝试:
想要通过拖放消息 2 与双"进行更改.
或者我想用Single"更改消息 1.
上面的代码只是一个更大的项目的测试.
Nothing is working except the setOnDragDetected handler. Why?
Example what I'm trying:
Want to change via drag and drop Message 2 with "Double".
Or I want to change Message 1 with "Single".
The code above is just a test for a larger project.
推荐答案
你需要
startDragAndDrop()
onDRAG_DETECTED
源事件acceptTransferModes()
对DRAG_OVER
目标事件- 和
event.getDragboard().getString()
上DRAG_DROPPED
目标事件
startDragAndDrop()
onDRAG_DETECTED
source eventacceptTransferModes()
onDRAG_OVER
target event- and
event.getDragboard().getString()
onDRAG_DROPPED
target event
查看完整示例:
@Override
public void start( Stage primaryStage ) throws Exception
{
HBox box = new HBox();
// ListView
ListView<String> list = new ListView<String>( FXCollections.observableArrayList( "Single", "Double", "Suite", "Family App" ) );
list.setCellFactory( new Callback<ListView<String>, ListCell<String>>()
{
@Override
public ListCell<String> call( ListView<String> param )
{
ListCell<String> listCell = new ListCell<String>()
{
@Override
protected void updateItem( String item, boolean empty )
{
super.updateItem( item, empty );
setText( item );
}
};
listCell.setOnDragDetected( ( MouseEvent event ) ->
{
System.out.println( "listcell setOnDragDetected" );
Dragboard db = listCell.startDragAndDrop( TransferMode.COPY );
ClipboardContent content = new ClipboardContent();
content.putString( listCell.getItem() );
db.setContent( content );
event.consume();
} );
return listCell;
}
} );
//TreeView
TreeItem<String> rootItem = new TreeItem<>( "Inbox" );
rootItem.setExpanded( true );
for ( int i = 1; i < 6; i++ )
{
TreeItem<String> item = new TreeItem<>( "Message " + i );
rootItem.getChildren().add( item );
}
TreeView<String> treeView = new TreeView<>( rootItem );
treeView.setEditable( true );
treeView.setCellFactory( new Callback<TreeView<String>, TreeCell<String>>()
{
@Override
public TreeCell<String> call( TreeView<String> stringTreeView )
{
TreeCell<String> treeCell = new TreeCell<String>()
{
@Override
protected void updateItem( String item, boolean empty )
{
super.updateItem( item, empty );
if ( item != null )
{
setText( item );
}
}
};
treeCell.setOnDragEntered( ( DragEvent event ) ->
{
treeCell.setStyle( "-fx-background-color: aqua;" );
} );
treeCell.setOnDragExited( ( DragEvent event ) ->
{
treeCell.setStyle( "" );
} );
treeCell.setOnDragOver( ( DragEvent event ) ->
{
Dragboard db = event.getDragboard();
if ( db.hasString() )
{
event.acceptTransferModes( TransferMode.COPY_OR_MOVE );
}
event.consume();
} );
treeCell.setOnDragDropped( ( DragEvent event ) ->
{
System.out.println( "treeCell.setOnDragDropped" );
Dragboard db = event.getDragboard();
boolean success = false;
if ( db.hasString() )
{
System.out.println( "Dropped: " + db.getString() );
treeCell.getTreeItem().getChildren().add( new TreeItem<>( db.getString() ) );
treeCell.getTreeItem().setExpanded( true );
success = true;
}
event.setDropCompleted( success );
event.consume();
} );
return treeCell;
}
} );
box.getChildren().addAll( list, treeView );
primaryStage.setScene( new Scene( box ) );
primaryStage.show();
}
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