From 4406bd4aedd97c78833370c7d7b9934c95aefd27 Mon Sep 17 00:00:00 2001
From: Carlos Galindo <carlos.s.galindo@gmail.com>
Date: Fri, 13 Sep 2019 10:31:46 +0200
Subject: [PATCH] Table: added moving via drag and drop

---
 .../controller/DraggableRowFactory.java       | 92 +++++++++++++++++++
 .../jstudy/controller/TableController.java    |  1 +
 2 files changed, 93 insertions(+)
 create mode 100644 src/main/java/es/kauron/jstudy/controller/DraggableRowFactory.java

diff --git a/src/main/java/es/kauron/jstudy/controller/DraggableRowFactory.java b/src/main/java/es/kauron/jstudy/controller/DraggableRowFactory.java
new file mode 100644
index 0000000..c53bc70
--- /dev/null
+++ b/src/main/java/es/kauron/jstudy/controller/DraggableRowFactory.java
@@ -0,0 +1,92 @@
+package es.kauron.jstudy.controller;
+
+import javafx.collections.ObservableList;
+import javafx.scene.control.TableRow;
+import javafx.scene.control.TableView;
+import javafx.scene.input.ClipboardContent;
+import javafx.scene.input.DataFormat;
+import javafx.scene.input.Dragboard;
+import javafx.scene.input.TransferMode;
+
+import java.util.ArrayList;
+import java.util.List;
+
+class DraggableRowFactory<S> {
+    private static final DataFormat SERIALIZED_MIME_TYPE = new DataFormat("application/x-java-serialized-object");
+
+    private final ObservableList<S> data;
+    private final List<S> dragging = new ArrayList<>();
+
+    DraggableRowFactory(ObservableList<S> data) {
+        this.data = data;
+    }
+
+    TableRow<S> generator(TableView<S> table) {
+        TableRow<S> row = new TableRow<>();
+        row.setOnDragDetected((event) -> {
+            if (!row.isEmpty() && table.getItems().size() == data.size()) {
+                Integer index = row.getIndex();
+                dragging.clear();
+                dragging.addAll(table.getSelectionModel().getSelectedItems());
+                Dragboard db = row.startDragAndDrop(TransferMode.MOVE);
+                ClipboardContent cc = new ClipboardContent();
+                cc.put(SERIALIZED_MIME_TYPE, index);
+                db.setContent(cc);
+                event.consume();
+            }
+        });
+        row.setOnDragOver((event) -> {
+            Dragboard db = event.getDragboard();
+            if (db.hasContent(SERIALIZED_MIME_TYPE)) {
+                if (row.getIndex() != (Integer) db.getContent(SERIALIZED_MIME_TYPE)) {
+                    event.acceptTransferModes(TransferMode.COPY_OR_MOVE);
+                    event.consume();
+                }
+            }
+        });
+        row.setOnDragDropped((event) -> {
+            Dragboard db = event.getDragboard();
+            if (!db.hasContent(SERIALIZED_MIME_TYPE))
+                return;
+            int dropIndex;
+            S item = null;
+            if (row.isEmpty()) {
+                dropIndex = table.getItems().size();
+            } else {
+                dropIndex = row.getIndex();
+                item = table.getItems().get(dropIndex);
+            }
+            int delta = 0;
+            if (item != null) {
+                while (dragging.contains(item)) {
+                    delta = 1;
+                    --dropIndex;
+                    if (dropIndex < 0) {
+                        item = null;
+                        dropIndex = 0;
+                        break;
+                    }
+                    item = table.getItems().get(dropIndex);
+                }
+            }
+            data.removeAll(dragging);
+            if (item != null)
+                dropIndex = table.getItems().indexOf(item) + delta;
+            else if (dropIndex != 0)
+                dropIndex = table.getItems().size();
+
+            table.getSelectionModel().clearSelection();
+
+            for (S s : dragging) {
+                data.add(dropIndex, s);
+                table.getSelectionModel().select(dropIndex);
+                dropIndex++;
+            }
+
+            event.setDropCompleted(true);
+            dragging.clear();
+            event.consume();
+        });
+        return row;
+    }
+}
diff --git a/src/main/java/es/kauron/jstudy/controller/TableController.java b/src/main/java/es/kauron/jstudy/controller/TableController.java
index 99786d0..f2c8468 100644
--- a/src/main/java/es/kauron/jstudy/controller/TableController.java
+++ b/src/main/java/es/kauron/jstudy/controller/TableController.java
@@ -86,6 +86,7 @@ public class TableController implements Initializable {
         this.data = FXCollections.observableArrayList(list);
         this.filtered = data.filtered((item) -> true);
         this.parent = controller;
+        table.setRowFactory(new DraggableRowFactory<>(data)::generator);
         table.setItems(filtered);
         this.file = file;
         saved.set(file != null);