JScrollPane

Question

के अंदर एक जेटीरी नोड खींचते समय स्क्रॉलिंग गति को कैसे गति दें JScrollPane में मेरे पास JTree है। JTree इतना लंबा है इसलिए पेड़ के शीर्ष से नीचे तक नोड खींचने में कुछ समय लगता है। JScrollPane स्क्रॉल नोड खींचते समय, लेकिन माउस व्हील का उपयोग करके स्क्रॉल करते समय लगभग उतना तेज़ नहीं होता है। चयनित उत्तर here में सुझाए गए अनुसार setUnitIncrement लागू करने से माउस व्हील स्क्रॉल गति तेज हो जाती है, लेकिन नोड खींचने की गति में कोई बदलाव नहीं आता है। setBlockIncrement लागू करते समय भी यही सच है। नोड खींचते समय स्क्रॉल की गति उसी तरह होती है जैसे कि मुझे ऊपर या नीचे तीर पकड़ना था और JTree को इस तरह से पार करना था।

मैं नोड को खींचने की गति को कैसे बढ़ा सकता हूं?

अद्यतन 1:

यहाँ एक SSCCE के रूप में अनुरोध है। इस कोड का अधिकांश मैं here से फिसल गया क्योंकि मेरी समस्या का वर्णन करने में यह अच्छा है। बस उस नोड को पेड़ के उस हिस्से में खींचें जो स्क्रॉल फलक में दिखाई नहीं दे रहा है और आप देखेंगे कि धीमी स्क्रॉलिंग कितनी धीमी है। मैं यही तेज़ करना चाहता हूं।

package example; 

import java.awt.datatransfer.*; 
import java.util.*; 
import javax.swing.*; 
import javax.swing.tree.*; 

public class Example { 

    private JScrollPane getContent() { 
     ArrayList<String> arrayList = new ArrayList<String>(); 
     for(int i = 0; i < 3000; i++) { 
      arrayList.add(String.format("Node %d", i)); 
     } 
     DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root"); 
     for(String s : arrayList) { 
      root.add(new DefaultMutableTreeNode(s)); 
     } 
     JTree tree = new JTree(root); 
     tree.setDragEnabled(true); 
     tree.setDropMode(DropMode.ON_OR_INSERT); 
     tree.setTransferHandler(new TreeTransferHandler()); 
     tree.getSelectionModel().setSelectionMode(TreeSelectionModel.CONTIGUOUS_TREE_SELECTION); 
     expandTree(tree); 
     return new JScrollPane(tree); 
    } 

    private void expandTree(JTree tree) { 
     DefaultMutableTreeNode root = (DefaultMutableTreeNode)tree.getModel().getRoot(); 
     Enumeration e = root.breadthFirstEnumeration(); 
     while(e.hasMoreElements()) { 
      DefaultMutableTreeNode node = (DefaultMutableTreeNode)e.nextElement(); 
      if(node.isLeaf()) { 
       continue; 
      } 
      int row = tree.getRowForPath(new TreePath(node.getPath())); 
      tree.expandRow(row); 
     } 
    } 

    public static void main(String[] args) { 
     JFrame f = new JFrame(); 
     f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     f.add(new Example().getContent()); 
     f.setSize(400, 400); 
     f.setLocation(200, 200); 
     f.setVisible(true); 
    } 
} 

class TreeTransferHandler extends TransferHandler { 

    DataFlavor nodesFlavor; 
    DataFlavor[] flavors = new DataFlavor[1]; 
    DefaultMutableTreeNode[] nodesToRemove; 

    public TreeTransferHandler() { 
     try { 
      String mimeType = DataFlavor.javaJVMLocalObjectMimeType 
        + ";class=\"" 
        + javax.swing.tree.DefaultMutableTreeNode[].class.getName() 
        + "\""; 
      nodesFlavor = new DataFlavor(mimeType); 
      flavors[0] = nodesFlavor; 
     } catch(ClassNotFoundException e) { 
      System.out.println("ClassNotFound: " + e.getMessage()); 
     } 
    } 

    public boolean canImport(TransferHandler.TransferSupport support) { 
     if(!support.isDrop()) { 
      return false; 
     } 
     support.setShowDropLocation(true); 
     if(!support.isDataFlavorSupported(nodesFlavor)) { 
      return false; 
     } 
     // Do not allow a drop on the drag source selections. 
     JTree.DropLocation dl = (JTree.DropLocation)support.getDropLocation(); 
     JTree tree = (JTree)support.getComponent(); 
     int dropRow = tree.getRowForPath(dl.getPath()); 
     int[] selRows = tree.getSelectionRows(); 
     for(int i = 0; i < selRows.length; i++) { 
      if(selRows[i] == dropRow) { 
       return false; 
      } 
     } 
     // Do not allow MOVE-action drops if a non-leaf node is 
     // selected unless all of its children are also selected. 
     int action = support.getDropAction(); 
     if(action == MOVE) { 
      return haveCompleteNode(tree); 
     } 
     // Do not allow a non-leaf node to be copied to a level 
     // which is less than its source level. 
     TreePath dest = dl.getPath(); 
     DefaultMutableTreeNode target = (DefaultMutableTreeNode)dest.getLastPathComponent(); 
     TreePath path = tree.getPathForRow(selRows[0]); 
     DefaultMutableTreeNode firstNode = (DefaultMutableTreeNode)path.getLastPathComponent(); 
     if(firstNode.getChildCount() > 0 && target.getLevel() < firstNode.getLevel()) { 
      return false; 
     } 
     return true; 
    } 

    private boolean haveCompleteNode(JTree tree) { 
     int[] selRows = tree.getSelectionRows(); 
     TreePath path = tree.getPathForRow(selRows[0]); 
     DefaultMutableTreeNode first = (DefaultMutableTreeNode)path.getLastPathComponent(); 
     int childCount = first.getChildCount(); 
     // first has children and no children are selected. 
     if(childCount > 0 && selRows.length == 1) { 
      return false; 
     } 
     // first may have children. 
     for(int i = 1; i < selRows.length; i++) { 
      path = tree.getPathForRow(selRows[i]); 
      DefaultMutableTreeNode next = (DefaultMutableTreeNode)path.getLastPathComponent(); 
      if(first.isNodeChild(next)) { 
       // Found a child of first. 
       if(childCount > selRows.length - 1) { 
        // Not all children of first are selected. 
        return false; 
       } 
      } 
     } 
     return true; 
    } 

    protected Transferable createTransferable(JComponent c) { 
     JTree tree = (JTree)c; 
     TreePath[] paths = tree.getSelectionPaths(); 
     if(paths != null) { 
      // Make up a node array of copies for transfer and 
      // another for/of the nodes that will be removed in 
      // exportDone after a successful drop. 
      List<DefaultMutableTreeNode> copies = new ArrayList<DefaultMutableTreeNode>(); 
      List<DefaultMutableTreeNode> toRemove = new ArrayList<DefaultMutableTreeNode>(); 
      DefaultMutableTreeNode node = (DefaultMutableTreeNode)paths[0].getLastPathComponent(); 
      DefaultMutableTreeNode copy = copy(node); 
      copies.add(copy); 
      toRemove.add(node); 
      for(int i = 1; i < paths.length; i++) { 
       DefaultMutableTreeNode next = (DefaultMutableTreeNode)paths[i].getLastPathComponent(); 
       // Do not allow higher level nodes to be added to list. 
       if(next.getLevel() < node.getLevel()) { 
        break; 
       } else if(next.getLevel() > node.getLevel()) { // child node 
        copy.add(copy(next)); 
        // node already contains child 
       } else {          // sibling 
        copies.add(copy(next)); 
        toRemove.add(next); 
       } 
      } 
      DefaultMutableTreeNode[] nodes = copies.toArray(new DefaultMutableTreeNode[copies.size()]); 
      nodesToRemove = toRemove.toArray(new DefaultMutableTreeNode[toRemove.size()]); 
      return new NodesTransferable(nodes); 
     } 
     return null; 
    } 

    /** 
    * Defensive copy used in createTransferable. 
    */ 
    private DefaultMutableTreeNode copy(TreeNode node) { 
     return new DefaultMutableTreeNode(node); 
    } 

    protected void exportDone(JComponent source, Transferable data, int action) { 
     if((action & MOVE) == MOVE) { 
      JTree tree = (JTree)source; 
      DefaultTreeModel model = (DefaultTreeModel)tree.getModel(); 
      // Remove nodes saved in nodesToRemove in createTransferable. 
      for(int i = 0; i < nodesToRemove.length; i++) { 
       model.removeNodeFromParent(nodesToRemove[i]); 
      } 
     } 
    } 

    public int getSourceActions(JComponent c) { 
     return COPY_OR_MOVE; 
    } 

    public boolean importData(TransferHandler.TransferSupport support) { 
     if(!canImport(support)) { 
      return false; 
     } 
     // Extract transfer data. 
     DefaultMutableTreeNode[] nodes = null; 
     try { 
      Transferable t = support.getTransferable(); 
      nodes = (DefaultMutableTreeNode[])t.getTransferData(nodesFlavor); 
     } catch(UnsupportedFlavorException ufe) { 
      System.out.println("UnsupportedFlavor: " + ufe.getMessage()); 
     } catch(java.io.IOException ioe) { 
      System.out.println("I/O error: " + ioe.getMessage()); 
     } 
     // Get drop location info. 
     JTree.DropLocation dl = (JTree.DropLocation)support.getDropLocation(); 
     int childIndex = dl.getChildIndex(); 
     TreePath dest = dl.getPath(); 
     DefaultMutableTreeNode parent = (DefaultMutableTreeNode)dest.getLastPathComponent(); 
     JTree tree = (JTree)support.getComponent(); 
     DefaultTreeModel model = (DefaultTreeModel)tree.getModel(); 
     // Configure for drop mode. 
     int index = childIndex; // DropMode.INSERT 
     if(childIndex == -1) {  // DropMode.ON 
      index = parent.getChildCount(); 
     } 
     // Add data to model. 
     for(int i = 0; i < nodes.length; i++) { 
      model.insertNodeInto(nodes[i], parent, index++); 
     } 
     return true; 
    } 

    public String toString() { 
     return getClass().getName(); 
    } 

    public class NodesTransferable implements Transferable { 

     DefaultMutableTreeNode[] nodes; 

     public NodesTransferable(DefaultMutableTreeNode[] nodes) { 
      this.nodes = nodes; 
     } 

     public Object getTransferData(DataFlavor flavor) 
       throws UnsupportedFlavorException { 
      if(!isDataFlavorSupported(flavor)) { 
       throw new UnsupportedFlavorException(flavor); 
      } 
      return nodes; 
     } 

     public DataFlavor[] getTransferDataFlavors() { 
      return flavors; 
     } 

     public boolean isDataFlavorSupported(DataFlavor flavor) { 
      return nodesFlavor.equals(flavor); 
     } 
    } 
} 

सफलता!

मैं ड्रैग करते समय स्क्रॉलिंग को तेज़ करने में सक्षम था। असल में मैं स्क्रॉल स्पीड वैरिएबल बनाने में भी सक्षम था कि कर्सर पेड़ के ऊपर या नीचे कितना करीब है। मैं इसे बनाने से बहुत आसान हो गया था। श्रोता की भी आवश्यकता नहीं थी। मैंने जो जोड़ा है उसे देखने के लिए बस इन दो कोड उदाहरणों को अलग करें।

package example; 

import java.awt.Point; 
import java.awt.Rectangle; 
import java.awt.datatransfer.*; 
import java.util.*; 
import javax.swing.*; 
import javax.swing.tree.*; 

public class Example { 

    private JScrollPane getContent() { 
     ArrayList<String> arrayList = new ArrayList<String>(); 
     for(int i = 0; i < 3000; i++) { 
      arrayList.add(String.format("Node %d", i)); 
     } 
     DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root"); 
     for(String s : arrayList) { 
      root.add(new DefaultMutableTreeNode(s)); 
     } 
     JTree tree = new JTree(root); 
     tree.setDragEnabled(true); 
     tree.setDropMode(DropMode.ON_OR_INSERT); 
     tree.setTransferHandler(new TreeTransferHandler()); 
     tree.getSelectionModel().setSelectionMode(TreeSelectionModel.CONTIGUOUS_TREE_SELECTION); 
     expandTree(tree); 
     return new JScrollPane(tree); 
    } 

    private void expandTree(JTree tree) { 
     DefaultMutableTreeNode root = (DefaultMutableTreeNode)tree.getModel().getRoot(); 
     Enumeration e = root.breadthFirstEnumeration(); 
     while(e.hasMoreElements()) { 
      DefaultMutableTreeNode node = (DefaultMutableTreeNode)e.nextElement(); 
      if(node.isLeaf()) { 
       continue; 
      } 
      int row = tree.getRowForPath(new TreePath(node.getPath())); 
      tree.expandRow(row); 
     } 
    } 

    public static void main(String[] args) { 
     JFrame f = new JFrame(); 
     f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     f.add(new Example().getContent()); 
     f.setSize(400, 400); 
     f.setLocation(200, 200); 
     f.setVisible(true); 
    } 
} 

class TreeTransferHandler extends TransferHandler { 

    DataFlavor nodesFlavor; 
    DataFlavor[] flavors = new DataFlavor[1]; 
    DefaultMutableTreeNode[] nodesToRemove; 

    public TreeTransferHandler() { 
     try { 
      String mimeType = DataFlavor.javaJVMLocalObjectMimeType 
        + ";class=\"" 
        + javax.swing.tree.DefaultMutableTreeNode[].class.getName() 
        + "\""; 
      nodesFlavor = new DataFlavor(mimeType); 
      flavors[0] = nodesFlavor; 
     } catch(ClassNotFoundException e) { 
      System.out.println("ClassNotFound: " + e.getMessage()); 
     } 
    } 

    public boolean canImport(TransferHandler.TransferSupport support) { 
     if(!support.isDrop()) { 
      return false; 
     } 

     boolean isScrolling = false; 
     JTree tree = (JTree)support.getComponent(); 
     JViewport vp = (JViewport)tree.getParent(); 
     Point vpMousePosition = vp.getMousePosition(); 
     Rectangle treeVisibleRectangle = tree.getVisibleRect(); 

     // Don't attempt scroll if mouse isn't over tree 
     if(vpMousePosition != null) { 
      Integer newY = null; 

      // Make sure we aren't already scrolled all the way down 
      if(tree.getHeight() - treeVisibleRectangle.y != vp.getHeight()) { 
       /* 
       * Get Y coordinate for scrolling down 
       */ 
       if(vp.getHeight() - vpMousePosition.y < 10) { 
        newY = treeVisibleRectangle.y + 500; 
       } else if(vp.getHeight() - vpMousePosition.y < 20) { 
        newY = treeVisibleRectangle.y + 400; 
       } else if(vp.getHeight() - vpMousePosition.y < 30) { 
        newY = treeVisibleRectangle.y + 300; 
       } else if(vp.getHeight() - vpMousePosition.y < 40) { 
        newY = treeVisibleRectangle.y + 200; 
       } else if(vp.getHeight() - vpMousePosition.y < 50) { 
        newY = treeVisibleRectangle.y + 100; 
       } else if(vp.getHeight() - vpMousePosition.y < 60) { 
        newY = treeVisibleRectangle.y + 50; 
       } else if(vp.getHeight() - vpMousePosition.y < 70) { 
        newY = treeVisibleRectangle.y + 25; 
       } else if(vp.getHeight() - vpMousePosition.y < 80) { 
        newY = treeVisibleRectangle.y + 10; 
       } 
      } 

      // Make sure we aren't already scrolled all the way up 
      if(newY == null && treeVisibleRectangle.y != 0) { 
       /* 
       * Get Y coordinate for scrolling up 
       */ 
       if(10 > vpMousePosition.y) { 
        newY = treeVisibleRectangle.y - 500; 
       } else if(20 > vpMousePosition.y) { 
        newY = treeVisibleRectangle.y - 400; 
       } else if(30 > vpMousePosition.y) { 
        newY = treeVisibleRectangle.y - 300; 
       } else if(40 > vpMousePosition.y) { 
        newY = treeVisibleRectangle.y - 200; 
       } else if(50 > vpMousePosition.y) { 
        newY = treeVisibleRectangle.y - 100; 
       } else if(60 > vpMousePosition.y) { 
        newY = treeVisibleRectangle.y - 50; 
       } else if(70 > vpMousePosition.y) { 
        newY = treeVisibleRectangle.y - 25; 
       } else if(80 > vpMousePosition.y) { 
        newY = treeVisibleRectangle.y - 10; 
       } 
      } 

      // Do the scroll 
      if(newY != null ) { 
       Rectangle treeNewVisibleRectangle = new Rectangle(treeVisibleRectangle.x, newY, treeVisibleRectangle.width, treeVisibleRectangle.height); 
       tree.scrollRectToVisible(treeNewVisibleRectangle); 
       isScrolling = true; 
      } 
     } 

     if(isScrolling) { 
      return false; 
     } 

     support.setShowDropLocation(true); 
     if(!support.isDataFlavorSupported(nodesFlavor)) { 
      return false; 
     } 
     // Do not allow a drop on the drag source selections. 
     JTree.DropLocation dl = (JTree.DropLocation)support.getDropLocation(); 
     int dropRow = tree.getRowForPath(dl.getPath()); 
     int[] selRows = tree.getSelectionRows(); 
     for(int i = 0; i < selRows.length; i++) { 
      if(selRows[i] == dropRow) { 
       return false; 
      } 
     } 
     // Do not allow MOVE-action drops if a non-leaf node is 
     // selected unless all of its children are also selected. 
     int action = support.getDropAction(); 
     if(action == MOVE) { 
      return haveCompleteNode(tree); 
     } 
     // Do not allow a non-leaf node to be copied to a level 
     // which is less than its source level. 
     TreePath dest = dl.getPath(); 
     DefaultMutableTreeNode target = (DefaultMutableTreeNode)dest.getLastPathComponent(); 
     TreePath path = tree.getPathForRow(selRows[0]); 
     DefaultMutableTreeNode firstNode = (DefaultMutableTreeNode)path.getLastPathComponent(); 
     if(firstNode.getChildCount() > 0 && target.getLevel() < firstNode.getLevel()) { 
      return false; 
     } 
     return true; 
    } 

    private boolean haveCompleteNode(JTree tree) { 
     int[] selRows = tree.getSelectionRows(); 
     TreePath path = tree.getPathForRow(selRows[0]); 
     DefaultMutableTreeNode first = (DefaultMutableTreeNode)path.getLastPathComponent(); 
     int childCount = first.getChildCount(); 
     // first has children and no children are selected. 
     if(childCount > 0 && selRows.length == 1) { 
      return false; 
     } 
     // first may have children. 
     for(int i = 1; i < selRows.length; i++) { 
      path = tree.getPathForRow(selRows[i]); 
      DefaultMutableTreeNode next = (DefaultMutableTreeNode)path.getLastPathComponent(); 
      if(first.isNodeChild(next)) { 
       // Found a child of first. 
       if(childCount > selRows.length - 1) { 
        // Not all children of first are selected. 
        return false; 
       } 
      } 
     } 
     return true; 
    } 

    protected Transferable createTransferable(JComponent c) { 
     JTree tree = (JTree)c; 
     TreePath[] paths = tree.getSelectionPaths(); 
     if(paths != null) { 
      // Make up a node array of copies for transfer and 
      // another for/of the nodes that will be removed in 
      // exportDone after a successful drop. 
      List<DefaultMutableTreeNode> copies = new ArrayList<DefaultMutableTreeNode>(); 
      List<DefaultMutableTreeNode> toRemove = new ArrayList<DefaultMutableTreeNode>(); 
      DefaultMutableTreeNode node = (DefaultMutableTreeNode)paths[0].getLastPathComponent(); 
      DefaultMutableTreeNode copy = copy(node); 
      copies.add(copy); 
      toRemove.add(node); 
      for(int i = 1; i < paths.length; i++) { 
       DefaultMutableTreeNode next = (DefaultMutableTreeNode)paths[i].getLastPathComponent(); 
       // Do not allow higher level nodes to be added to list. 
       if(next.getLevel() < node.getLevel()) { 
        break; 
       } else if(next.getLevel() > node.getLevel()) { // child node 
        copy.add(copy(next)); 
        // node already contains child 
       } else {          // sibling 
        copies.add(copy(next)); 
        toRemove.add(next); 
       } 
      } 
      DefaultMutableTreeNode[] nodes = copies.toArray(new DefaultMutableTreeNode[copies.size()]); 
      nodesToRemove = toRemove.toArray(new DefaultMutableTreeNode[toRemove.size()]); 
      return new NodesTransferable(nodes); 
     } 
     return null; 
    } 

    /** 
    * Defensive copy used in createTransferable. 
    */ 
    private DefaultMutableTreeNode copy(TreeNode node) { 
     return new DefaultMutableTreeNode(node); 
    } 

    protected void exportDone(JComponent source, Transferable data, int action) { 
     if((action & MOVE) == MOVE) { 
      JTree tree = (JTree)source; 
      DefaultTreeModel model = (DefaultTreeModel)tree.getModel(); 
      // Remove nodes saved in nodesToRemove in createTransferable. 
      for(int i = 0; i < nodesToRemove.length; i++) { 
       model.removeNodeFromParent(nodesToRemove[i]); 
      } 
     } 
    } 

    public int getSourceActions(JComponent c) { 
     return COPY_OR_MOVE; 
    } 

    public boolean importData(TransferHandler.TransferSupport support) { 
     if(!canImport(support)) { 
      return false; 
     } 
     // Extract transfer data. 
     DefaultMutableTreeNode[] nodes = null; 
     try { 
      Transferable t = support.getTransferable(); 
      nodes = (DefaultMutableTreeNode[])t.getTransferData(nodesFlavor); 
     } catch(UnsupportedFlavorException ufe) { 
      System.out.println("UnsupportedFlavor: " + ufe.getMessage()); 
     } catch(java.io.IOException ioe) { 
      System.out.println("I/O error: " + ioe.getMessage()); 
     } 
     // Get drop location info. 
     JTree.DropLocation dl = (JTree.DropLocation)support.getDropLocation(); 
     int childIndex = dl.getChildIndex(); 
     TreePath dest = dl.getPath(); 
     DefaultMutableTreeNode parent = (DefaultMutableTreeNode)dest.getLastPathComponent(); 
     JTree tree = (JTree)support.getComponent(); 
     DefaultTreeModel model = (DefaultTreeModel)tree.getModel(); 
     // Configure for drop mode. 
     int index = childIndex; // DropMode.INSERT 
     if(childIndex == -1) {  // DropMode.ON 
      index = parent.getChildCount(); 
     } 
     // Add data to model. 
     for(int i = 0; i < nodes.length; i++) { 
      model.insertNodeInto(nodes[i], parent, index++); 
     } 
     return true; 
    } 

    public String toString() { 
     return getClass().getName(); 
    } 

    public class NodesTransferable implements Transferable { 

     DefaultMutableTreeNode[] nodes; 

     public NodesTransferable(DefaultMutableTreeNode[] nodes) { 
      this.nodes = nodes; 
     } 

     public Object getTransferData(DataFlavor flavor) 
       throws UnsupportedFlavorException { 
      if(!isDataFlavorSupported(flavor)) { 
       throw new UnsupportedFlavorException(flavor); 
      } 
      return nodes; 
     } 

     public DataFlavor[] getTransferDataFlavors() { 
      return flavors; 
     } 

     public boolean isDataFlavorSupported(DataFlavor flavor) { 
      return nodesFlavor.equals(flavor); 
     } 
    } 
} 

Answer 1

जब यह SDK के साथ अच्छी तरह से काम नहीं कर रहा, की तुलना में मैं अपने hackish तरीकों शुरू कर रहा हूँ, इस मामले में यह इस बात का एक प्रकार है: माउस सुनने। जब माउस एक पिक्सेल नीचे चला गया, तो एक घटना बनाने के बजाय माउस ने उसी दिशा में 100 पिक्सेल स्थानांतरित कर दिया। विंडोज़ में, एक्सेल में यदि आप टास्क बार के नीचे खींचते हैं तो माउस स्क्रॉलिंग को बढ़ा देगा। यहां कुछ ऐसा होना चाहिए, यह एक कोशिश के लायक है।