Drag & Drop-Dateien in Matlab GUI

Question

Ich versuche, eine Möglichkeit zu finden, Drag & Drop in meiner Matlab GUI zu verwenden. Der nächste, den ich gefunden habe, ist this.

Allerdings möchte ich das Ergebnis wie folgt aussehen:

Wenn eine Datei gelöscht wurde, alles was ich brauche ist der Pfad der Datei und ein Aufruf an meine Ladefunktion.

Alle Vorschläge werden sehr geschätzt!

Answer 1

This submission von Maarten van der Seijs auf dem Dateiaustausch scheint es zu lösen.

Es erstellt eine Callback-Funktion, die mit Java-Swing-GUI-Komponenten gekoppelt werden kann, wie in der beigefügten Demo gezeigt.

Es eine Java-Klasse verwendet, die um java.awt.dnd.DropTarget eine dünne Hülle ist:

import java.awt.dnd.*; 
import java.awt.datatransfer.*; 
import java.util.*; 
import java.io.File; 
import java.io.IOException; 

public class MLDropTarget extends DropTarget 
{ 
    /** 
    * Modified DropTarget to be used for drag & drop in MATLAB UI control. 
    */ 
    private static final long serialVersionUID = 1L; 
    private int droptype; 
    private Transferable t; 
    private String[] transferData; 

    public static final int DROPERROR = 0; 
    public static final int DROPTEXTTYPE = 1; 
    public static final int DROPFILETYPE = 2; 

    @SuppressWarnings("unchecked") 
    @Override 
    public synchronized void drop(DropTargetDropEvent evt) { 

     // Make sure drop is accepted 
     evt.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE); 

     // Set droptype to zero 
     droptype = DROPERROR;   

     // Get transferable and analyze 
     t = evt.getTransferable(); 

     try { 
      if (t.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) { 
       // Interpret as list of files 
       List<File> fileList = (ArrayList<File>) t.getTransferData(DataFlavor.javaFileListFlavor); 
       transferData = new String[fileList.size()]; 
       for (int i = 0; i < fileList.size(); i++) 
        transferData[i] = fileList.get(i).getAbsolutePath(); 
       droptype = DROPFILETYPE; 
      } 
      else if (t.isDataFlavorSupported(DataFlavor.stringFlavor)) { 
       // Interpret as string    
       transferData[0] = (String) t.getTransferData(DataFlavor.stringFlavor); 
       droptype = DROPTEXTTYPE; 
      } 

     } catch (UnsupportedFlavorException e) { 
      droptype = DROPERROR; 
      super.drop(evt);    
      return; 
     } catch (IOException e) { 
      droptype = DROPERROR; 
      super.drop(evt); 
      return; 
     } 

     // Call built-in drop method (fire MATLAB Callback)  
     super.drop(evt); 
    } 

    public int getDropType() { 
     return droptype; 
    } 
    public Transferable getTransferable() { 
     return t; 
    } 
    public String[] getTransferData() { 
     return transferData; 
    } 
} 

, die dann und durch eine MATLAB-Klasse aufgerufen wird initialisiert:

classdef (CaseInsensitiveProperties) dndcontrol < handle 
%DNDCONTROL Class for Drag & Drop functionality. 
% obj = DNDCONTROL(javaobj) creates a dndcontrol object for the specified 
% Java object, such as 'javax.swing.JTextArea' or 'javax.swing.JList'. Two 
% callback functions are available: obj.DropFileFcn and obj.DropStringFcn, 
% that listen to drop actions of respectively system files or plain text. 
% 
% The Drag & Drop control class relies on a Java class that need to be 
% visible on the Java classpath. To initialize, call the static method 
% dndcontrol.initJava(). The Java class can be adjusted and recompiled if 
% desired. 
% 
% DNDCONTROL Properties: 
%  Parent   - The associated Java object. 
%  DropFileFcn  - Callback function for system files. 
%  DropStringFcn  - Callback function for plain text. 
% 
% DNDCONTROL Methods: 
%  dndcontrol  - Constructs the DNDCONTROL object. 
% 
% DNDCONTROL Static Methods: 
%  defaultDropFcn - Default callback function for drop events. 
%  demo    - Runs the demonstration script. 
%  initJava   - Initializes the Java class. 
%  isInitialized  - Checks if the Java class is visible. 
% 
% A demonstration is available from the static method dndcontrol.demo(). 
% 
% Example: 
%  dndcontrol.initJava(); 
%  dndcontrol.demo(); 
% 
% See also: 
%  uicontrol, javaObjectEDT.  
% 
% Written by: Maarten van der Seijs, 2015. 
% Version: 1.0, 13 October 2015. 


    properties (Hidden) 
     dropTarget;     
    end 

    properties (Dependent) 
     %PARENT The associated Java object. 
     Parent; 
    end 

    properties 
     %DROPFILEFCN Callback function executed upon dropping of system files. 
     DropFileFcn;   
     %DROPSTRINGFCN Callback function executed upon dropping of plain text. 
     DropStringFcn;   
    end 

    methods (Static) 
     function initJava() 
     %INITJAVA Initializes the required Java class. 

      %Add java folder to javaclasspath if necessary 
      if ~dndcontrol.isInitialized(); 
       classpath = fileparts(mfilename('fullpath'));     
       javaclasspath(classpath);     
      end 
     end 

     function TF = isInitialized()    
     %ISINITIALIZED Returns true if the Java class is initialized. 

      TF = (exist('MLDropTarget','class') == 8); 
     end       
    end 

    methods 
     function obj = dndcontrol(Parent,DropFileFcn,DropStringFcn) 
     %DNDCONTROL Drag & Drop control constructor. 
     % obj = DNDCONTROL(javaobj) contstructs a DNDCONTROL object for 
     % the given parent control javaobj. The parent control should be a 
     % subclass of java.awt.Component, such as most Java Swing widgets. 
     % 
     % obj = DNDCONTROL(javaobj,DropFileFcn,DropStringFcn) sets the 
     % callback functions for dropping of files and text. 

      % Check for Java class 
      assert(dndcontrol.isInitialized(),'Javaclass MLDropTarget not found. Call dndcontrol.initJava() for initialization.') 

      % Construct DropTarget    
      obj.dropTarget = handle(javaObjectEDT('MLDropTarget'),'CallbackProperties'); 
      set(obj.dropTarget,'DropCallback',{@dndcontrol.DndCallback,obj}); 
      set(obj.dropTarget,'DragEnterCallback',{@dndcontrol.DndCallback,obj}); 

      % Set DropTarget to Parent 
      if nargin >=1, Parent.setDropTarget(obj.dropTarget); end 

      % Set callback functions 
      if nargin >=2, obj.DropFileFcn = DropFileFcn; end 
      if nargin >=3, obj.DropStringFcn = DropStringFcn; end 
     end 

     function set.Parent(obj, Parent) 
      if isempty(Parent) 
       obj.dropTarget.setComponent([]); 
       return 
      end 
      if isa(Parent,'handle') && ismethod(Parent,'java') 
       Parent = Parent.java; 
      end 
      assert(isa(Parent,'java.awt.Component'),'Parent is not a subclass of java.awt.Component.') 
      assert(ismethod(Parent,'setDropTarget'),'DropTarget cannot be set on this object.') 

      obj.dropTarget.setComponent(Parent); 
     end 

     function Parent = get.Parent(obj) 
      Parent = obj.dropTarget.getComponent(); 
     end 
    end 

    methods (Static, Hidden = true) 
     %% Callback functions 
     function DndCallback(jSource,jEvent,obj) 

      if jEvent.isa('java.awt.dnd.DropTargetDropEvent') 
       % Drop event  
       try 
        switch jSource.getDropType() 
         case 0 
          % No success. 
         case 1 
          % String dropped. 
          string = char(jSource.getTransferData()); 
          if ~isempty(obj.DropStringFcn) 
           evt = struct(); 
           evt.DropType = 'string'; 
           evt.Data = string;         
           feval(obj.DropStringFcn,obj,evt); 
          end 
         case 2 
          % File dropped. 
          files = cell(jSource.getTransferData());        
          if ~isempty(obj.DropFileFcn) 
           evt = struct(); 
           evt.DropType = 'file'; 
           evt.Data = files;         
           feval(obj.DropFileFcn,obj,evt); 
          end 
        end 

        % Set dropComplete 
        jEvent.dropComplete(true); 
       catch ME 
        % Set dropComplete 
        jEvent.dropComplete(true); 
        rethrow(ME) 
       end        

      elseif jEvent.isa('java.awt.dnd.DropTargetDragEvent') 
       % Drag event        
       action = java.awt.dnd.DnDConstants.ACTION_COPY; 
       jEvent.acceptDrag(action); 
      end    
     end 
    end 

    methods (Static) 
     function defaultDropFcn(src,evt) 
     %DEFAULTDROPFCN Default drop callback. 
     % DEFAULTDROPFCN(src,evt) accepts the following arguments: 
     %  src - The dndcontrol object. 
     %  evt - A structure with fields 'DropType' and 'Data'. 

      fprintf('Drop event from %s component:\n',char(src.Parent.class())); 
      switch evt.DropType 
       case 'file' 
        fprintf('Dropped files:\n'); 
        for n = 1:numel(evt.Data) 
         fprintf('%d %s\n',n,evt.Data{n}); 
        end 
       case 'string' 
        fprintf('Dropped text:\n%s\n',evt.Data); 
      end 
     end    

     function [dndobj,hFig] = demo() 
     %DEMO Demonstration of the dndcontrol class functionality. 
     % dndcontrol.demo() runs the demonstration. Make sure that the 
     % Java class is visible in the Java classpath. 

      % Initialize Java class 
      dndcontrol.initJava(); 

      % Create figure 
      hFig = figure(); 

      % Create Java Swing JTextArea 
      jTextArea = javaObjectEDT('javax.swing.JTextArea', ... 
       sprintf('Drop some files or text content here.\n\n')); 

      % Create Java Swing JScrollPane 
      jScrollPane = javaObjectEDT('javax.swing.JScrollPane', jTextArea); 
      jScrollPane.setVerticalScrollBarPolicy(jScrollPane.VERTICAL_SCROLLBAR_ALWAYS); 

      % Add Scrollpane to figure 
      [~,hContainer] = javacomponent(jScrollPane,[],hFig); 
      set(hContainer,'Units','normalized','Position',[0 0 1 1]); 

      % Create dndcontrol for the JTextArea object 
      dndobj = dndcontrol(jTextArea); 

      % Set Drop callback functions 
      dndobj.DropFileFcn = @demoDropFcn; 
      dndobj.DropStringFcn = @demoDropFcn; 

      % Callback function 
      function demoDropFcn(~,evt) 
       switch evt.DropType 
        case 'file' 
         jTextArea.append(sprintf('Dropped files:\n')); 
         for n = 1:numel(evt.Data) 
          jTextArea.append(sprintf('%d %s\n',n,evt.Data{n})); 
         end 
        case 'string' 
         jTextArea.append(sprintf('Dropped text:\n%s\n',evt.Data)); 
       end 
       jTextArea.append(sprintf('\n')); 
      end 
     end 
    end  
end