我对此示例代码有疑问。
import java.io.File;
import java.io.IOException;
import java.nio.file.DirectoryStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.BasicFileAttributes;
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.ActionEvent;
import javafx.event.Event;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeView;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
public class CopyOfTreeViewSample extends Application {
public static Image folderCollapseImage=new Image(ClassLoader.getSystemResourceAsStream("treeviewsample/folder.png"));
public static Image folderExpandImage=new Image(ClassLoader.getSystemResourceAsStream("treeviewsample/folder-open.png"));
public static Image fileImage=new Image(ClassLoader.getSystemResourceAsStream("treeviewsample/text-x-generic.png"));
public static Image rootImage = new Image(ClassLoader.getSystemResourceAsStream("treeviewsample/computer.png"));
private TreeView treeView;
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage stage) {
Scene scene = new Scene(new Group());
stage.setTitle("Sample");
stage.setWidth(300);
stage.setHeight(500);
VBox vbox = new VBox();
vbox.setLayoutX(20);
vbox.setLayoutY(20);
TreeItem<String> root = new SimpleFileTreeItem(Paths.get("C:\\Users\\Jake"), true);
treeView = new TreeView<String>(root);
Button b = new Button("Change");
b.setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent arg0) {
// TODO Auto-generated method stub
////// How do i this section write code?//////
}
});
vbox.getChildren().addAll(treeView,b);
vbox.setSpacing(10);
((Group) scene.getRoot()).getChildren().add(vbox);
stage.setScene(scene);
stage.show();
}
public class SimpleFileTreeItem extends TreeItem<String> {
private boolean isRoot = false;
private boolean isFirstTimeChildren = true;
private boolean isFirstTimeLeaf = true;
private boolean isLeaf;
private boolean isDirectory;
public boolean isDirectory(){return(this.isDirectory);}
private String fullPath;
public String getFullPath(){return(this.fullPath);}
public SimpleFileTreeItem(Path f, Boolean flag) {
super(f.toString());
fullPath = f.toString();
isRoot = flag;
if(!isRoot)
{
if(Files.isDirectory(f))
{
isDirectory = true;
this.setGraphic(new ImageView(folderCollapseImage));
}
else
{
isDirectory = false;
this.setGraphic(new ImageView(fileImage));
}
//set the value
if(!fullPath.endsWith(File.separator)){
String value=f.toString();
int indexOf=value.lastIndexOf(File.separator);
if(indexOf>0){
this.setValue(value.substring(indexOf+1));
}else{
this.setValue(value);
}
}
this.addEventHandler(TreeItem.branchExpandedEvent(),new EventHandler(){
@Override
public void handle(Event e){
SimpleFileTreeItem source=(SimpleFileTreeItem)e.getSource();
if(source.isDirectory()&&source.isExpanded()){
ImageView iv=(ImageView)source.getGraphic();
iv.setImage(folderExpandImage);
}
}
});
this.addEventHandler(TreeItem.branchCollapsedEvent(),new EventHandler(){
@Override
public void handle(Event e){
SimpleFileTreeItem source=(SimpleFileTreeItem)e.getSource();
if(source.isDirectory()&&!source.isExpanded()){
ImageView iv=(ImageView)source.getGraphic();
iv.setImage(folderCollapseImage);
}
}
});
}
else
{
this.setExpanded(true);
if(Files.isDirectory(f))
{
isDirectory = true;
this.setGraphic(new ImageView(rootImage));
}
else
{
isDirectory = false;
this.setGraphic(new ImageView(fileImage));
}
}
}
@Override
public ObservableList<TreeItem<String>> getChildren() {
if (isFirstTimeChildren) {
isFirstTimeChildren = false;
/*
* First getChildren() call, so we actually go off and determine the
* children of the File contained in this TreeItem.
*/
super.getChildren().setAll(buildChildren(this));
}
return super.getChildren();
}
@Override
public boolean isLeaf() {
if (isFirstTimeLeaf) {
isFirstTimeLeaf = false;
File f = new File(fullPath);
isLeaf = f.isFile();
}
return isLeaf;
}
/**
* Returning a collection of type ObservableList containing TreeItems, which
* represent all children available in handed TreeItem.
*
* @param TreeItem
* the root node from which children a collection of TreeItem
* should be created.
* @return an ObservableList<TreeItem<File>> containing TreeItems, which
* represent all children available in handed TreeItem. If the
* handed TreeItem is a leaf, an empty list is returned.
*/
private ObservableList<TreeItem<String>> buildChildren(TreeItem<String> TreeItem) {
File f = new File(fullPath);
if (f != null && f.isDirectory()) {
File[] files = f.listFiles();
if (files != null) {
ObservableList<TreeItem<String>> children = FXCollections
.observableArrayList();
for (File childFile : files) {
children.add(new SimpleFileTreeItem(childFile.toPath(), false));
}
return children;
}
}
return FXCollections.emptyObservableList();
}
}
我想选择与按下按钮时路径对应的文件。
我的eclipse项目路径是c：\ java \ samplecode。
我试图通过使用Absolutepath来解决，结果是c：\ java \ samplecode \ samplefile.txt
我想要这条路径。（c：\ Users \ jake \ samplefile.txt）
感谢您的建议和提示。
答案 0 :(得分：0)
使用您拥有的设置，您应该可以
b.setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent event) {
SimpleFileTreeItem<String> selectedItem = (SimpleFileTreeItem)treeView.getSelectionModel().getSelectedItem();
if (selectedItem != null) {
String pathString = selectedItem.getFullPath();
}
}
});
（如果你也这样做
b.disableProperty().bind(
Bindings.isNull(treeView.getSelectionModel().selectedItemProperty()));
然后你可以安全地跳过对处理程序中null的检查。）
我认为更好的方法是让SimpleFileTreeItem成为TreeItem<Path>。然后你只需保留Path作为树项的值，你就可以使用单元工厂来显示文件名。
以下是使用此方法的示例。我拿出了图像（因此可以不依赖外部资源执行）以及许多其他不必要的代码。
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.stream.Collectors;
import javafx.application.Application;
import javafx.beans.binding.Bindings;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TreeCell;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeView;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
public class CopyOfTreeViewSample extends Application {
private TreeView<Path> treeView;
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage stage) {
stage.setTitle("Sample");
stage.setWidth(300);
stage.setHeight(500);
VBox vbox = new VBox();
vbox.setPadding(new Insets(20));
TreeItem<Path> root = new SimpleFileTreeItem(
Paths.get(System.getProperty("user.home")));
root.setExpanded(true);
treeView = new TreeView<Path>(root);
treeView.setCellFactory(treeView -> new TreeCell<Path>() {
@Override
public void updateItem(Path path, boolean empty) {
super.updateItem(path, empty);
if (empty) {
setText(null);
} else {
setText(path.getFileName().toString());
}
}
});
Button b = new Button("Change");
b.disableProperty().bind(Bindings.isNull(treeView.getSelectionModel().selectedItemProperty()));
b.setOnAction(event -> {
Path selectedPath = treeView.getSelectionModel().getSelectedItem().getValue() ;
// do something with selectedPath...
System.out.println(selectedPath);
});
vbox.getChildren().addAll(treeView, b);
vbox.setSpacing(10);
Scene scene = new Scene(vbox);
stage.setScene(scene);
stage.show();
}
public class SimpleFileTreeItem extends TreeItem<Path> {
private boolean isFirstTimeChildren = true;
private boolean isFirstTimeLeaf = true;
private boolean isLeaf;
public boolean isDirectory() {
return Files.isDirectory(getValue());
}
public SimpleFileTreeItem(Path f) {
super(f);
}
@Override
public ObservableList<TreeItem<Path>> getChildren() {
if (isFirstTimeChildren) {
isFirstTimeChildren = false;
/*
* First getChildren() call, so we actually go off and determine
* the children of the File contained in this TreeItem.
*/
super.getChildren().setAll(buildChildren());
}
return super.getChildren();
}
@Override
public boolean isLeaf() {
if (isFirstTimeLeaf) {
isFirstTimeLeaf = false;
isLeaf = Files.exists(getValue()) && ! Files.isDirectory(getValue());
}
return isLeaf;
}
/**
* Returning a collection of type ObservableList containing TreeItems,
* which represent all children of this TreeITem.
*
*
* @return an ObservableList<TreeItem<File>> containing TreeItems, which
* represent all children available in this TreeItem. If the
* handed TreeItem is a leaf, an empty list is returned.
*/
private ObservableList<TreeItem<Path>> buildChildren() {
if (Files.isDirectory(getValue())) {
try {
return Files.list(getValue())
.map(SimpleFileTreeItem::new)
.collect(Collectors.toCollection(() -> FXCollections.observableArrayList()));
} catch (IOException e) {
e.printStackTrace();
return FXCollections.emptyObservableList();
}
}
return FXCollections.emptyObservableList();
}
}
}