Java：如何將JLabel移動到JPanel的中心？

所以在我的GUI中，我有一個JFrame是一個borderlayout。在北部和西部有一個菜單欄和一些圖形用戶界面。在CENTER中，有一個JLabel。我希望它移動到JPanel的中心（水平和垂直）。我如何正確地做到這一點？我試過盒子佈局和網格佈局。一個要求是我不能使用gridbag佈局。Java：如何將JLabel移動到JPanel的中心？

public class NewClass extends JFrame{ 
    public NewClass() { 
     setVisible(true); 
     setSize(500,500); 
     setDefaultCloseOperation (EXIT_ON_CLOSE); 

//menubar 
     JMenuBar bar = new JMenuBar(); 
     JMenu editMenu = new JMenu("Edit"); 
     JMenuItem mItem = new JMenuItem("Cut"); // edit->cut 
     editMenu.add(mItem); 
     mItem = new JMenuItem("Copy"); // edit->copy 
     editMenu.add(mItem); 
     mItem = new JMenuItem("Paste"); // edit->paste 
     editMenu.add(mItem); 
     bar.add(editMenu); 
     this.setJMenuBar(bar); 

//north panel 
     JPanel topPanel = new JPanel(); 
     this.add(topPanel,BorderLayout.NORTH); 
     JLabel myLabel = new JLabel ("Label:") ; 
     topPanel.add(myLabel); 
     JButton mytopButton = new JButton ("Push Me"); 
     topPanel.add(mytopButton); 

//left panel 
     JPanel leftPanel = new JPanel(); 
     leftPanel.setBorder (new TitledBorder("Commands:")); 
     leftPanel.setLayout (new GridLayout (10,1)); 
     this.add(leftPanel,BorderLayout.WEST); 
     JButton myLeftButton1 = new JButton ("Button 1"); 
     leftPanel.add(myLeftButton1); 
     JButton myLeftButton2 = new JButton ("Button 2"); 
     leftPanel.add(myLeftButton2); 
     JButton myLeftButton3 = new JButton ("Button3"); 
     leftPanel.add(myLeftButton3); 

//center panel 
     JPanel centerPanel = new JPanel(); 
     this.add(centerPanel,BorderLayout.CENTER); 
     JLabel mapLabel = new JLabel("Test_String"); //move this to center of JPanel 
     centerPanel.add(mapLabel); 
     centerPanel.setBorder (new EtchedBorder(Color.black,Color.black)); 
     centerPanel.setBackground (Color.white); 
    } 
}

來源

2013-10-30 user2837858

另請參閱[這個答案]（http://stackoverflow.com/a/7181197/418556）右邊的兩個佈局（以一個組件爲中心）。 –

回答。感謝大家。

JPanel centerPanel = new JPanel(); 
    centerPanel.setLayout (new GridLayout()); //added 
    this.add(centerPanel,BorderLayout.CENTER); 
    JLabel mapLabel = new JLabel("Test_String"); 
    mapLabel.setHorizontalAlignment(SwingConstants.CENTER); //added 
    mapLabel.setVerticalAlignment(SwingConstants.CENTER); //added 
    centerPanel.add(mapLabel); 
    centerPanel.setBorder (new EtchedBorder(Color.black,Color.black)); 
    centerPanel.setBackground (Color.white);

來源

2013-10-30 05:35:53 user2837858

然後，您應該接受將您導向setHorizontalAlignment和setVerticalAlignment方法的答案。 – camickr