[英]JavaFX: How to highlight certain Items in a TreeView
我正在嘗試為JavaFX中的TreeView
實現搜索功能。 我想在用戶按下Enter鍵時突出顯示所有匹配項。 因此,我在我的TreeItem
添加了一個boolean isHighlighted
,在TreeCell
的updateItem
,我檢查了該項目是否為isHighlighted
,如果是的話,我會應用某種CSS。 在搜索時不可見的項目/單元格中一切正常,當我滾動到它們時,它們會正確突出顯示。 問題是:如何“重繪”在搜索時可見的TreeCell,以便它們反映其項目是否為isHighlighted
? 我的控制器當前沒有對TreeView
創建的TreeCells
的任何引用。
此答案是基於這一個 ,但適合於TreeView
的代替TableView
,並更新為使用JavaFX的8功能(大大減少的代碼所需的量)。
一種策略是維護一個與搜索匹配的TreeItems
的ObservableSet
(有時這對於您可能想要的其他功能很有用)。 使用CSS PseudoClass
和外部CSS文件突出顯示所需的單元格。 你可以創建一個BooleanBinding
在電池工廠結合細胞的treeItemProperty
和ObservableSet
,計算到true
,如果集合包含電池的電流樹項目。 然后只需向綁定注冊一個偵聽器,並在其更改時更新單元的偽類狀態。
這是SSCCE。 它包含一棵樹,其項目是Integer
數值。 當您在搜索框中鍵入內容時,它將匹配值是輸入值倍數的內容,從而更新搜索。
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Random;
import java.util.Set;
import javafx.application.Application;
import javafx.beans.binding.Bindings;
import javafx.beans.binding.BooleanBinding;
import javafx.collections.FXCollections;
import javafx.collections.ObservableSet;
import javafx.css.PseudoClass;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.TextField;
import javafx.scene.control.TextFormatter;
import javafx.scene.control.TreeCell;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeView;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;
public class TreeWithSearchAndHighlight extends Application {
@Override
public void start(Stage primaryStage) {
TreeView<Integer> tree = new TreeView<>(createRandomTree(100));
// keep track of items that match our search:
ObservableSet<TreeItem<Integer>> searchMatches = FXCollections.observableSet(new HashSet<>());
// cell factory returns an instance of TreeCell implementation defined below.
// pass the cell implementation a reference to the set of search matches
tree.setCellFactory(tv -> new SearchHighlightingTreeCell(searchMatches));
// search text field:
TextField textField = new TextField();
// allow only numeric input:
textField.setTextFormatter(new TextFormatter<Integer>(change ->
change.getControlNewText().matches("\\d*")
? change
: null));
// when the text changes, update the search matches:
textField.textProperty().addListener((obs, oldText, newText) -> {
// clear search:
searchMatches.clear();
// if no text, or 0, just exit:
if (newText.isEmpty()) {
return ;
}
int searchValue = Integer.parseInt(newText);
if (searchValue == 0) {
return ;
}
// search for matching nodes and put them in searchMatches:
Set<TreeItem<Integer>> matches = new HashSet<>();
searchMatchingItems(tree.getRoot(), matches, searchValue);
searchMatches.addAll(matches);
});
BorderPane root = new BorderPane(tree, textField, null, null, null);
BorderPane.setMargin(textField, new Insets(5));
BorderPane.setMargin(tree, new Insets(5));
Scene scene = new Scene(root, 600, 600);
// stylesheet sets style for cells matching search by using the selector
// .tree-cell:search-match
// (specified in the initalization of the Pseudoclass at the top of the code)
scene.getStylesheets().add("tree-highlight-search.css");
primaryStage.setScene(scene);
primaryStage.show();
}
// find all tree items whose value is a multiple of the search value:
private void searchMatchingItems(TreeItem<Integer> searchNode, Set<TreeItem<Integer>> matches, int searchValue) {
if (searchNode.getValue() % searchValue == 0) {
matches.add(searchNode);
}
for (TreeItem<Integer> child : searchNode.getChildren()) {
searchMatchingItems(child, matches, searchValue);
}
}
// build a random tree with numNodes nodes (all nodes expanded):
private TreeItem<Integer> createRandomTree(int numNodes) {
List<TreeItem<Integer>> items = new ArrayList<>();
TreeItem<Integer> root = new TreeItem<>(1);
root.setExpanded(true);
items.add(root);
Random rng = new Random();
for (int i = 2 ; i <= numNodes ; i++) {
TreeItem<Integer> item = new TreeItem<>(i);
item.setExpanded(true);
TreeItem<Integer> parent = items.get(rng.nextInt(items.size()));
parent.getChildren().add(item);
items.add(item);
}
return root ;
}
public static class SearchHighlightingTreeCell extends TreeCell<Integer> {
// must keep reference to binding to prevent premature garbage collection:
private BooleanBinding matchesSearch ;
public SearchHighlightingTreeCell(ObservableSet<TreeItem<Integer>> searchMatches) {
// pseudoclass for highlighting state
// css can set style with selector
// .tree-cell:search-match { ... }
PseudoClass searchMatch = PseudoClass.getPseudoClass("search-match");
// initialize binding. Evaluates to true if searchMatches
// contains the current treeItem
// note the binding observes both the treeItemProperty and searchMatches,
// so it updates if either one changes:
matchesSearch = Bindings.createBooleanBinding(() ->
searchMatches.contains(getTreeItem()),
treeItemProperty(), searchMatches);
// update the pseudoclass state if the binding value changes:
matchesSearch.addListener((obs, didMatchSearch, nowMatchesSearch) ->
pseudoClassStateChanged(searchMatch, nowMatchesSearch));
}
// update the text when the item displayed changes:
@Override
protected void updateItem(Integer item, boolean empty) {
super.updateItem(item, empty);
setText(empty ? null : "Item "+item);
}
}
public static void main(String[] args) {
launch(args);
}
}
CSS文件tree-highlight-search.css只需包含突出顯示的單元格的樣式即可:
.tree-cell:search-match {
-fx-background: yellow ;
}
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.