Java拖放不起作用

Question

我正在嘗試Java拖放操作。動作通過動員我想要描繪的圖像的路徑隨後標記，但未被繪製，有人可以請幫忙嗎？

class MyDragDropListener implements DropTargetListener { 

    public void drop(DropTargetDropEvent event) { 

     // Accept copy drops 
     event.acceptDrop(DnDConstants.ACTION_COPY); 

     // Get the transfer which can provide the dropped item data 
     Transferable transferable = event.getTransferable(); 

     // Get the data formats of the dropped item 
     DataFlavor[] flavors = transferable.getTransferDataFlavors(); 

     // Loop through the flavors 
     for (DataFlavor flavor : flavors) { 

      try { 

       // If the drop items are files 
       if (flavor.isFlavorJavaFileListType()) { 


        //  List files = (List) transferable.getTransferData(flavor); 

        Object f = transferable.getTransferData(flavor); 
        // Loop them through 
        // for (File file : files) { 

        // Print out the file path 
//      System.out.println("File path is '" + f.getPath() + "'."); 

        String cesta = f.toString(); 
        String typ = ""; 
        String cesta2 = ""; 
        for (int i = 1; i < cesta.length() - 1; i++) { 
         if (cesta.charAt(i) == '\\') { 
          cesta2 = cesta2 + '/'; 
         } else { 
          cesta2 = cesta2 + cesta.charAt(i); 
         } 
        } 
        for (int i = cesta2.length() - 1; i > 0; i--) { 
         if (cesta2.charAt(i) == '.') { 
          break; 
         } 
         typ = typ + cesta2.charAt(i); 

        } 
        typ = new StringBuilder(typ).reverse().toString().toLowerCase(); 


        MojeOkno mo = new MojeOkno(); 
        // Inform that the drop is complete 
        mo.VlozObrazekDoLabelu(cesta2); 
        System.out.println("METODA PROBEHLA"); 

       } 

      } catch (Exception e) { 

       // Print out the error stack 
       e.printStackTrace(); 

      } 
     } 

     event.dropComplete(true); 

    } 

    public void dragEnter(DropTargetDragEvent event) { 
    } 

    public void dragExit(DropTargetEvent event) { 
    } 

    public void dragOver(DropTargetDragEvent event) { 
    } 

    public void dropActionChanged(DropTargetDragEvent event) { 
    } 
} 



public void VlozObrazekDoLabelu(String Mojecesta) { 

     System.out.println("Cesta k obrazku: " + Mojecesta); 

     try { 

      img = ImageIO.read(new File(Mojecesta)); 


      Graphics2D g = (Graphics2D) PanelProObrazek_jPanel1.getGraphics(); 
      g.drawImage(img, 3, 3, PanelProObrazek_jPanel1.getWidth() - 6, PanelProObrazek_jPanel1.getHeight() - 6, this); 
      System.out.println("Dostal jsem se do try"); 

     } catch (Exception e) { 
      System.out.println("CHYBA"); 

     } 

    } 

來自捷克共和國的問候。

Answer 1

的問題是在MyDragDropListener.drop(DropTargetDropEvent event)

// CESTA2 == PATH TO IMG 
MojeOkno mo = new MojeOkno(); 
mo.InserImgToPanel(cesta2); 

您創建了一個新的 MojeOkno，這就是爲什麼它不會工作。做出幾點修改：

// 1. method Callmeafterstart 
MyDragDropListener myDragDropListener = new MyDragDropListener(this); 

// 2. class MyDragDropListener 
private MojeOkno mojeOkno; 
public MyDragDropListener(MojeOkno mojeOkno) { 
    this.mojeOkno = mojeOkno; 
} 

// 3. method drop 
// CESTA2 == PATH TO IMG 
mojeOkno.InserImgToPanel(cesta2);