SWT(JFace)体验之拖曳效果

演示代码如下：

package swt_jface.demo11;import org.eclipse.swt.SWT;import org.eclipse.swt.dnd.DND;import org.eclipse.swt.dnd.DragSource;import org.eclipse.swt.dnd.DragSourceEvent;import org.eclipse.swt.dnd.DragSourceListener;import org.eclipse.swt.dnd.DropTarget;import org.eclipse.swt.dnd.DropTargetEvent;import org.eclipse.swt.dnd.DropTargetListener;import org.eclipse.swt.dnd.TextTransfer;import org.eclipse.swt.dnd.Transfer;import org.eclipse.swt.events.DisposeEvent;import org.eclipse.swt.events.DisposeListener;import org.eclipse.swt.graphics.Font;import org.eclipse.swt.widgets.Display;import org.eclipse.swt.widgets.Label;import org.eclipse.swt.widgets.MessageBox;import org.eclipse.swt.widgets.Shell;public class WordJumbles {Display display = new Display();Shell shell = new Shell(display);String word;Label[] labelsRowOne;Label[] labelsRowTwo;Font font = new Font(display, "Arial", 18, SWT.BOLD);public void setDragSource(final Label label) {int operations = DND.DROP_MOVE;final DragSource dragSource = new DragSource(label, operations);Transfer[] formats = new Transfer[] { TextTransfer.getInstance()};dragSource.setTransfer(formats);dragSource.addDragListener(new DragSourceListener() {public void dragStart(DragSourceEvent event) {if (label.getText().length() == 0)event.doit = false;}public void dragSetData(DragSourceEvent event) {if (TextTransfer.getInstance().isSupportedType(event.dataType))event.data = label.getText();}public void dragFinished(DragSourceEvent event) {if (event.doit == true || event.detail == DND.DROP_MOVE) {label.setText("");}}});label.addDisposeListener(new DisposeListener() {public void widgetDisposed(DisposeEvent e) {dragSource.dispose();}});}public void setDropTarget(final Label label) {int operations = DND.DROP_MOVE;final DropTarget dropTarget = new DropTarget(label, operations);Transfer[] formats = new Transfer[] { TextTransfer.getInstance()};dropTarget.setTransfer(formats);dropTarget.addDropListener(new DropTargetListener() {public void dragEnter(DropTargetEvent event) {if(label.getText().length() != 0)event.detail = DND.DROP_NONE;}public void dragLeave(DropTargetEvent event) {}public void dragOperationChanged(DropTargetEvent event) {}public void dragOver(DropTargetEvent event) {}public void drop(DropTargetEvent event) {if (TextTransfer.getInstance().isSupportedType(event.currentDataType)) {String text = (String) event.data;label.setText(text);check();}}public void dropAccept(DropTargetEvent event) {}});label.addDisposeListener(new DisposeListener() {public void widgetDisposed(DisposeEvent e) {dropTarget.dispose();}});}private void check() {for(int i=0; i<word.length(); i++) {if(! labelsRowTwo[i].getText().equals(word.charAt(i) + ""))return;}MessageBox messageBox = new MessageBox(shell);messageBox.setMessage("Success!");messageBox.open();}public WordJumbles(String word) {this.word = word;shell.setText("Word Jumbles");labelsRowOne = new Label[word.length()];labelsRowTwo = new Label[word.length()];int width = 40;int[] randomPermutation = { 5, 2, 6, 3, 1, 4, 0 };for (int i = 0; i < word.length(); i++) {final Label labelRowOne = new Label(shell, SWT.BORDER);labelsRowOne[i] = labelRowOne;labelRowOne.setBounds(10 + width * i, 10, width - 5, width - 5);labelRowOne.setFont(font);labelRowOne.setText(word.charAt(randomPermutation[i]) + "");labelRowOne.setAlignment(SWT.CENTER);setDragSource(labelRowOne);setDropTarget(labelRowOne);final Label labelRowTwo = new Label(shell, SWT.BORDER);labelsRowTwo[i] = labelRowTwo;labelRowTwo.setBounds(10 + width * i,20 + width,width - 5,width - 5);labelRowTwo.setBackground(display.getSystemColor(SWT.COLOR_WHITE));labelRowTwo.setFont(font);labelRowTwo.setAlignment(SWT.CENTER);setDragSource(labelRowTwo);setDropTarget(labelRowTwo);}shell.pack();shell.open();while (!shell.isDisposed()) {if (!display.readAndDispatch()) {display.sleep();}}display.dispose();}public static void main(String[] args) {new WordJumbles("ECLIPSE");}}