JavaFX:在 onEditCommit 函数中使用 ListView.edit(int itemIndex)

Question

我正在尝试在 javaFX 中创建一个易于用户使用的可编辑 ListView 。为此，我使用了编辑提交功能。它通常非常擅长做我想做的事情，但我遇到了一个问题。每次用户编辑最后一个项目时，我希望它创建另一个项目并开始编辑它。这看起来好像是微不足道的，但是我在 setOnEditCommit 函数中运行 dit 函数时遇到了问题。这是我的代码:

 personList.setOnEditCommit(new EventHandler<ListView.EditEvent<String>>() {
        @Override
        public void handle(ListView.EditEvent<String> t) {
            personList.getItems().set(t.getIndex(), t.getNewValue());

            if(personList.getSelectionModel().getSelectedIndices().contains(personList.getItems().size()-1)) {
                int personNumber = personList.getItems().size() + 1;
                personList.getItems().add("person " + personNumber);
                personList.edit(personList.getItems().size()-1); //the line that is not working.
            }
        }

    });

注意:personlist 是一个 ListView

无论如何，是否可以在 setOnEditCommit 上的集合中运行编辑功能。谢谢。

Answer 1

基本问题是 commitHandler 的重新编辑被取消。有许多(且复杂的)路径可以触发取消，其中之一似乎是“修复”JDK-8094887这相当粗鲁地取消了对数据更改的任何编辑。

但这不可能是全部故事，因为在单元配置期间触发重新编辑后收到的取消，大致:

indexedCell.updateIndex(index)
-> listCell.indexChanged(oldIndex, newIndex)
-> listCell.updateFocus()
-> node.setFocused(xx)  //for some reason xx is false
-> cell.focusedListener 
-> cancelEdit()

运行下面的示例，编辑单个项目，按 ENTER 会产生输出:

edit start: 0   // start edit on last row
edit commit: 0  // commit the edit by items.set(...)
edit cancel: -1 // cancel triggered by modification
edit start: 1   // re-edit the added item
edit cancel: -1 // cancel triggered by cell config

我能想到的唯一出路是非常脆弱的:像您一样开始重新编辑，然后启动一个计时器，“等待”直到所有内部配置完成并再次编辑。显然，我们不想在生产代码中做任何事情;)

import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.scene.Scene;
import javafx.scene.control.ListView;
import javafx.scene.control.cell.TextFieldListCell;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;
import javafx.util.Duration;

/**
 * Trying to add item/start edit on new item in commitHandler:
 * https://stackoverflow.com/q/46047134/203657
 * 
 * one last try: use timer to start editing some time later ..
 */
public class ListViewAutoEditInHandler extends Application {

    private ListView<String> simpleList;
    private int expectedEditIndex = -1;
    private Timeline editTimer;

    /**
     * Callback for editTimer. Implemented to scroll to and force
     * edit of cell at expectedEditIndex.
     */
    private void checkEdit() {
        if (expectedEditIndex < 0) return;
        if (expectedEditIndex == simpleList.getEditingIndex()) {
            expectedEditIndex = -1;
            return;
        }
        int index = expectedEditIndex;
        expectedEditIndex = -1;
        simpleList.scrollTo(index);
        simpleList.edit(index);
    }

    @Override
    public void start(Stage primaryStage) {
        editTimer = new Timeline(new KeyFrame(Duration.millis(100), ae -> checkEdit() ));
        simpleList = new ListView<>(FXCollections.observableArrayList("Item1"));
        simpleList.setEditable(true);

        simpleList.setCellFactory(TextFieldListCell.forListView());

        simpleList.setOnEditStart(t -> p("edit start: " + t.getIndex()));
        simpleList.setOnEditCancel(t -> p("edit cancel: " + t.getIndex()));
        simpleList.setOnEditCommit(t -> {
            p("edit commit: " + t.getIndex());
            // any modification of the items will trigger a cancel
            simpleList.getItems().set(t.getIndex(), t.getNewValue());
            //  p("editing? " + simpleList.getEditingIndex());
            if (t.getIndex() == simpleList.getItems().size() - 1) {
                expectedEditIndex = t.getIndex() + 1;
                simpleList.getItems().add("newItem");
                simpleList.getSelectionModel().select(expectedEditIndex);
                simpleList.edit(expectedEditIndex);
                // ... so we start a timer to force
                // uncomment for a brittle solution ;)
                // editTimer.playFromStart();
            } else {
                // reset .. a bit paranoid here ;)
                expectedEditIndex = -1;
                editTimer.stop();
            }

        });


        BorderPane root = new BorderPane(simpleList);
        Scene scene = new Scene(root, 300, 250);

        primaryStage.setTitle("Hello World!");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    private static void p(String t) {
        System.out.println(t);
    }
    public static void main(String[] args) {
        launch(args);
    }
}