如何在Java Swing拖放過程中啓用工具提示顯示

Question

如何在執行拖放操作時顯示工具提示。 似乎在拖放操作期間工具提示顯示被禁用或未被觸發。 我想使用工具提示向用戶指出爲什麼拒絕被拒絕。

Answer 1

我工作的解決方案是在TransferHandler中手動創建工具提示。這裏是我添加的代碼：

public class TableTransferHandler extends TransferHandler { 
    private Popup tipWindow; 
    private int tipCol; 
    private int tipRow; 

    public boolean canImport(TransferHandler.TransferSupport support) { 
     .... 
     updateDropDeniedTooltip(support, deniedReason) 
    } 

    private void hideDropDeniedTooltip() { 
     if (tipWindow != null) { 
      tipWindow.hide(); 
      tipWindow = null; 
     } 
    } 

    private void updateDropDeniedTooltip(TransferHandler.TransferSupport support, String deniedReason) { 
     if (deniedReason != null) { 
      JTable.DropLocation dropLocation = (JTable.DropLocation)support.getDropLocation(); 
      JTable jtable = (JTable)support.getComponent(); 
      if (tipWindow != null) { 
       if (tipRow != dropLocation.getRow() || tipCol != dropLocation.getColumn()) { 
        hideDropDeniedTooltip(); 
       } 
      } 
      if (tipWindow == null) { 
       tipRow = dropLocation.getRow(); 
       tipCol = dropLocation.getColumn(); 
       JToolTip tip = jtable.createToolTip(); 
       tip.setTipText(result.getReason()); 
       PopupFactory popupFactory = PopupFactory.getSharedInstance(); 
       Rectangle cellRect = jtable.getCellRect(tipRow, tipCol, true); 
       Point location = jtable.getLocationOnScreen(); 
       location.x += cellRect.x; 
       location.y += cellRect.y; 
       tipWindow = popupFactory.getPopup(jtable, tip, location.x, location.y); 
       tipWindow.show(); 
      } 
     } 
     else { 
      hideDropDeniedTooltip(); 
     } 
    } 
} 

Answer 2

您可以利用Drop Location Rendering來達到類似的效果。