JavaFX：在onEditCommit函數中使用ListView.edit（int itemIndex）

Question

我正嘗試在javaFX中創建易於用戶使用的可編輯列表視圖。爲此，我使用了on編輯提交功能。我一般很擅長做我想做的事情，但是我遇到了一個問題。每次用戶編輯最後一個項目時，我都希望它創建另一個項目並開始編輯該項目。看起來好像這是微不足道的，但是我遇到了在setOnEditCommit函數中運行dit函數的問題。這裏是我的代碼：

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：personlist是一個ListView

有反正從與中集上setOnEditCommit運行編輯功能。謝謝。

Answer 1

基本問題是由commitHandler重新編輯被取消。有許多（錯綜複雜的）路徑可以觸發取消，其中一個似乎是對「JDK-8094887」的「修復」，它會粗暴地取消對數據更改的任何編輯。

但由於取消了重新編輯的單元配置過程中觸發後，大約收到了不能原委：

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

運行下面的例子中，編輯單個項目，按ENTER鍵產生輸出：

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 

唯一的出路，我可以拿出很脆：開始重新編輯爲你做什麼，然後又開始說，「等待」，直到所有的內部配置做了計時器，然後再次編輯。沒有什麼，我們希望在生產代碼做，很明顯;）

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); 
    } 
}