除非调整大小，否则JFrame窗口不会显示任何内容

Question

I have an Interface class that extends JFrame. I am creating 3 JPanels and adding them to a Container (Border Layout) in different areas of the layout.

When I run the application, nothing shows but a blank window and a title. If I resize the application it will then show all the content and work as intended.

I'm not sure what I did differently this time, I've used this method before and it works in previous programs.

Any help is appreciated.

Here is my Interface Class Constructor code: http://pastebin.com/4UyEXsBr

Code:

public class Interface extends JFrame implements ActionListener {

private Container contentPane;

private JPanel buttonPanel, userPanel;

private JButton loginButton, createUserButton, logoutButton, withdrawButton, depositButton, switchToRegisterButton, switchToLoginButton;

private JLabel headerLabel, inputTopJTFLabel, inputPW1JPFLabel, toastLabel, inputPW2JPFLabel;

public JTextField inputTopJTF;
public JPasswordField inputPW1JPF, inputPW2JPF;

JRootPane rootPane;

public Interface(int width, int height, String title) {

    //Setting up Interface
    setTitle(title);
    setSize(width, height);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setLocation(100,100);
    setVisible(true);

    Font header = new Font("TimesRoman", Font.PLAIN, 50);

    ///////////////////////BUTTON PANEL///////////////////////

    //Button Panel
    buttonPanel = new JPanel();

    //Buttons
    //loginButton
    loginButton = new JButton("Login");
    loginButton.addActionListener(this);
    loginButton.setAlignmentX(Component.CENTER_ALIGNMENT);

    //switchToRegisterButton
    switchToRegisterButton = new JButton("New User?");
    switchToRegisterButton.addActionListener(this);
    switchToRegisterButton.setAlignmentX(Component.CENTER_ALIGNMENT);

    //switchToLoginButton
    switchToLoginButton = new JButton("Switch to Login");
    switchToLoginButton.addActionListener(this);
    switchToLoginButton.setAlignmentX(Component.CENTER_ALIGNMENT);
    switchToLoginButton.setVisible(false);

    //createUserButton
    createUserButton = new JButton("Register");
    createUserButton.addActionListener(this);
    createUserButton.setAlignmentX(Component.CENTER_ALIGNMENT);
    createUserButton.setVisible(false);

    //logoutButton
    logoutButton = new JButton("Logout");
    logoutButton.addActionListener(this);
    logoutButton.setAlignmentX(Component.CENTER_ALIGNMENT);
    logoutButton.setVisible(false);

    //withdrawButton
    withdrawButton = new JButton("Withdraw");
    withdrawButton.addActionListener(this);
    withdrawButton.setAlignmentX(Component.CENTER_ALIGNMENT);
    withdrawButton.setVisible(false);

    //depositButton
    depositButton = new JButton("Deposit");
    depositButton.addActionListener(this);
    depositButton.setAlignmentX(Component.CENTER_ALIGNMENT);
    depositButton.setVisible(false);

    //Adding items to buttonPanel
    buttonPanel.add(loginButton);
    buttonPanel.add(switchToRegisterButton);
    buttonPanel.add(switchToLoginButton);
    buttonPanel.add(createUserButton);
    buttonPanel.add(logoutButton);
    buttonPanel.add(withdrawButton);
    buttonPanel.add(depositButton);

    ///////////////BODY PANEL//////////////////////

    //Body Panel
    userPanel = new JPanel();
    userPanel.setLayout(new BoxLayout(userPanel, BoxLayout.PAGE_AXIS));

    //JTextFields
    //inputTopJTF
    Dimension inputTopJTFDimension = new Dimension(100, 20);
    inputTopJTF = new JTextField();
    inputTopJTF.setMaximumSize(inputTopJTFDimension);

    //inputPW1JPF
    Dimension inputPW1JPFDimension = new Dimension(100, 20);
    inputPW1JPF = new JPasswordField();
    inputPW1JPF.setMaximumSize(inputPW1JPFDimension);

    //inputPW2JPF
    Dimension inputPW2JPFDimension = new Dimension(100, 20);
    inputPW2JPF = new JPasswordField();
    inputPW2JPF.setMaximumSize(inputPW2JPFDimension);
    inputPW2JPF.setVisible(false);

    //JLabels
    //toastLabel
    toastLabel = new JLabel("Please sign in or create new account.");
    toastLabel.setAlignmentX(Component.CENTER_ALIGNMENT);

    //inputTopJTFLabel
    inputTopJTFLabel = new JLabel("Username:");
    inputTopJTFLabel.setAlignmentX(Component.CENTER_ALIGNMENT);

    //inputPW1JPFLabel
    inputPW1JPFLabel = new JLabel("Password:");
    inputPW1JPFLabel.setAlignmentX(Component.CENTER_ALIGNMENT);

    //inputPW2JPFLabel
    inputPW2JPFLabel = new JLabel("Confirm Password:");
    inputPW2JPFLabel.setAlignmentX(Component.CENTER_ALIGNMENT);
    inputPW2JPFLabel.setVisible(false);

    //Adding items to userPanel
    userPanel.add(toastLabel);
    userPanel.add(inputTopJTFLabel);
    userPanel.add(inputTopJTF);
    userPanel.add(inputPW1JPFLabel);
    userPanel.add(inputPW1JPF);
    userPanel.add(inputPW2JPFLabel);
    userPanel.add(inputPW2JPF);

///////////////CONTENT PANE/////////////////////

//Content Pane
contentPane = getContentPane();

//JLabels
//headerLabel
headerLabel = new JLabel("Bank", SwingConstants.CENTER);
headerLabel.setFont(header);

//PAGE_START
contentPane.add(headerLabel, BorderLayout.PAGE_START);

//LINE_START

//CENTER
contentPane.add(userPanel, BorderLayout.CENTER);

//LINE_END

//PAGE_END
contentPane.add(buttonPanel, BorderLayout.PAGE_END);

userPanel.setFocusable(true);
userPanel.requestFocus();

//Default Button
rootPane = getRootPane();
rootPane.setDefaultButton(loginButton);

}

Answer 1

call

setVisible(true);

in last line .because component added after line setvisible will not be shown until you call repaint(),revalidate() .when you resize ,repaint() method get called and frame will visible correctly .so call setvisible after add all component

after line rootPane.setDefaultButton(loginButton); call setvisible

rootPane.setDefaultButton(loginButton);
setVisible(true);//after add all component to frame call setvisible method

this is full working code