我最近不得不為FlexGanttFX實現(xiàn)自動滾動功能，并認為我的解決方案可能對其他人有用。 您可以在下面的清單中找到它的基本概念。 主要思想是使用后臺線程來調(diào)整列表視圖使用的虛擬流節(jié)點的像素位置。 當檢測到“靠近”頂部或底部邊緣的拖拉時，線程開始。 “接近”由接近變量定義。

通過為接近值使用屬性以及為線程化工作使用類型“任務(wù)”和“服務(wù)”，顯然可以改進此代碼。

package com.dlsc;import javafx.application.Platform; import javafx.scene.Node; import javafx.scene.control.ListView; import javafx.scene.input.ClipboardContent; import javafx.scene.input.DragEvent; import javafx.scene.input.Dragboard; import javafx.scene.input.MouseEvent; import javafx.scene.input.TransferMode; import javafx.scene.layout.Region;/** Yes, unfortunately we need to use private API for this.*/ import com.sun.javafx.scene.control.skin.VirtualFlow;public class AutoscrollListView<T> extends ListView<T> {final double proximity = 20;public AutoscrollListView() {addEventFilter(MouseEvent.DRAG_DETECTED,evt -> startDrag());addEventFilter(DragEvent.DRAG_OVER,evt -> autoscrollIfNeeded(evt));addEventFilter(DragEvent.DRAG_EXITED,evt -> stopAutoScrollIfNeeded(evt));addEventFilter(DragEvent.DRAG_DROPPED,evt -> stopAutoScrollIfNeeded(evt));addEventFilter(DragEvent.DRAG_DONE,evt -> stopAutoScrollIfNeeded(evt));}private void startDrag() {Dragboard db = startDragAndDrop(TransferMode.MOVE);ClipboardContent content = new ClipboardContent();/** We have to add some content, otherwise drag over* will not be called.*/content.putString("dummy");db.setContent(content);}private void autoscrollIfNeeded(DragEvent evt) {evt.acceptTransferModes(TransferMode.ANY);/** Determine the "hot" region that will trigger automatic scrolling.* Ideally we use the clipped container of the list view skin but when* the rows are empty the dimensions of the clipped container will be* 0x0. In this case we try to use the virtual flow.*/Region hotRegion = getClippedContainer();if (hotRegion.getBoundsInLocal().getWidth() < 1) {hotRegion = this;if (hotRegion.getBoundsInLocal().getWidth() < 1) {stopAutoScrollIfNeeded(evt);return;}}double yOffset = 0;// y offsetdouble delta = evt.getSceneY() -hotRegion.localToScene(0, 0).getY();if (delta < proximity) {yOffset = -(proximity - delta);}delta = hotRegion.localToScene(0, 0).getY() +hotRegion.getHeight() -evt.getSceneY();if (delta < proximity) {yOffset = proximity - delta;}if (yOffset != 0) {autoscroll(yOffset);} else {stopAutoScrollIfNeeded(evt);}}private VirtualFlow<?> getVirtualFlow() {return (VirtualFlow<?>) lookup("VirtualFlow");}private Region getClippedContainer() {/** Safest way to find the clipped container. lookup() does not work at* all.*/for (Node child :getVirtualFlow().getChildrenUnmodifiable()) {if (child.getStyleClass().contains("clipped-container")) {return (Region) child;}}return null;}class ScrollThread extends Thread {private boolean running = true;private double yOffset;public ScrollThread() {super("Autoscrolling List View");setDaemon(true);}@Overridepublic void run() {/** Some initial delay, especially useful when* dragging something in from the outside.*/try {Thread.sleep(300);} catch (InterruptedException e1) {e1.printStackTrace();}while (running) {Platform.runLater(() -> {scrollY();});try {sleep(15);} catch (InterruptedException e) {e.printStackTrace();}}}private void scrollY() {VirtualFlow<?> flow = getVirtualFlow();flow.adjustPixels(yOffset);}public void stopRunning() {this.running = false;}public void setDelta(double yOffset) {this.yOffset = yOffset;}}private ScrollThread scrollThread;private void autoscroll(double yOffset) {if (scrollThread == null) {scrollThread = new ScrollThread();scrollThread.start();}scrollThread.setDelta(yOffset);}private void stopAutoScrollIfNeeded(DragEvent evt) {if (scrollThread != null) {scrollThread.stopRunning();scrollThread = null;}} }

翻譯自: https://www.javacodegeeks.com/2014/11/javafx-tip-15-listview-autoscrolling.html

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