java - 弹出菜单不显示

Question

这个想法是创建一个 JPopupMenu当我 LEFT CLICK 时，它会显示在感叹号正下方就可以了。
我没有使用 isPopupTrigger()方法，因为我创建了一个单独的 MouseInputHandler实现我的具体条件。
然而JPopupMenu不显示。
这是代码:

protected class LabelHandler extends MouseInputAdapter{


    @Override
    public void mouseClicked(MouseEvent e){
        JLabel cause = (JLabel) e.getSource();
        if(cause == saveLabel){
            try{
                desktop.open(f);
            }catch(IOException ex){
                ex.printStackTrace();
            }
        }else if(cause == downLabel){

            popup.show(ScreenRecorder.this, e.getX(),e.getY());
        }
    }

    @Override
    public void mouseEntered(MouseEvent e){
        JLabel cause = (JLabel) e.getSource();
        if(cause == saveLabel){
            saveLabel.setCursor(new Cursor(Cursor.HAND_CURSOR));
        }else if(cause == downLabel){
            downLabel.setCursor(new Cursor(Cursor.HAND_CURSOR));
        }
    }

    @Override
    public void mouseExited(MouseEvent e){
        JLabel cause = (JLabel) e.getSource();
        if(cause == saveLabel || cause == saveLabel){
            saveLabel.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
        }else if(cause == downLabel){
            downLabel.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
        }
    }
}

标签名为 downLabel因为它应该是一个向下的箭头，但无论如何，我在那里放了一个感叹号。请告诉我为什么 JPopupMenu 没有出现。是的，我用另一种方法设置了菜单。

编辑:

创建 JPopup 的代码:

public void setupJPopup(){
        encodingGroup.add(avi);
        encodingGroup.add(quicktime);

        popup.add(avi);
        popup.add(quicktime);
        popup.addSeparator();

        recordingAreaGroup.add(entireScreen);
        recordingAreaGroup.add(custom);

        popup.add(entireScreen);
        popup.add(custom);
        popup.addSeparator();

        cursorGroup.add(selectBlackCursor);
        cursorGroup.add(selectWhiteCursor);
        cursorGroup.add(selectNoCursor);

        selectCursor.add(selectBlackCursor);
        selectCursor.add(selectWhiteCursor);
        selectCursor.add(selectNoCursor);

        popup.add(selectCursor);
        popup.pack();
    }  

上述代码涉及的变量有:

/* Creating the JPopupMenu containing the various menu items */
    JPopupMenu popup = new JPopupMenu();

    ButtonGroup encodingGroup = new ButtonGroup();
    ButtonGroup recordingAreaGroup = new ButtonGroup();
    ButtonGroup cursorGroup = new ButtonGroup();

    /* Handler for labels*/
    LabelHandler labelHandler = new LabelHandler();

    JRadioButtonMenuItem avi = new JRadioButtonMenuItem("AVI",true);
    JRadioButtonMenuItem quicktime = new JRadioButtonMenuItem("QuickTime",false);
    JRadioButtonMenuItem entireScreen = new JRadioButtonMenuItem("Entire Screen",true);
    JRadioButtonMenuItem custom = new JRadioButtonMenuItem("Custom...",false);
    JMenu selectCursor = new JMenu("Select a cursor");
    JRadioButtonMenuItem selectWhiteCursor = new JRadioButtonMenuItem("White Cursor",true);
    JRadioButtonMenuItem selectBlackCursor = new JRadioButtonMenuItem("Black Cursor",false);
    JRadioButtonMenuItem selectNoCursor = new JRadioButtonMenuItem("No Cursor",false);
/* Icons for the cursors */
    Icon blackCursor = (Icon) new ImageIcon("src/images/blackCursor.png");
    Icon whiteCursor = (Icon) new ImageIcon("src/images/whiteCursor.png");

Answer 1

可以发一下popup的相关代码吗？ .

或者更好的 SSCCE .

我无法重现您的问题。

你应该使用

saveLabel.equals(cause)

读入

cause == saveLabel