【发布时间】：2015-09-17 16:43:52
【问题描述】：
我的JFrame 和null 布局不会显示任何内容......我尝试将组件添加到JPanel，然后将其设置为框架的内容窗格。最近（如下面的代码所示）我尝试直接添加到框架中。我正在使用 Java 8。
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Electog extends JFrame implements MouseListener, MouseMotionListener {
BlankArea blankArea;
JTextArea textArea;
static JFrame frame;
public static void main(String[] args) {
JFrame frame = new Electog();
frame.setTitle("Electog");
frame.setSize(Toolkit.getDefaultToolkit().getScreenSize());
frame.setVisible(true);
}
public Electog() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(null);
JRadioButton selectButton = new JRadioButton("Select");
selectButton.addKeyListener(new KeyListener() {
@Override
public void keyReleased(KeyEvent e) {
handleAction(e);
}
@Override
public void keyTyped(KeyEvent e) {
}
@Override
public void keyPressed(KeyEvent e) {
handleAction(e);
}
});
selectButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
handleAction(e);
}
public void actionEvent(ActionEvent e) {
handleAction(e);
}
});
selectButton.setSelected(true);
JRadioButton removeButton = new JRadioButton("Remove");
removeButton.addKeyListener(new KeyListener() {
@Override
public void keyReleased(KeyEvent e) {
handleAction(e);
}
@Override
public void keyTyped(KeyEvent e) {
}
@Override
public void keyPressed(KeyEvent e) {
handleAction(e);
}
});
removeButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
handleAction(e);
}
public void actionEvent(ActionEvent e) {
handleAction(e);
}
});
JRadioButton openButton = new JRadioButton("Open");
openButton.addKeyListener(new KeyListener() {
@Override
public void keyTyped(KeyEvent e) {
}
@Override
public void keyReleased(KeyEvent e) {
handleAction(e);
}
@Override
public void keyPressed(KeyEvent e) {
handleAction(e);
}
});
openButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
handleAction(e);
}
public void actionEvent(ActionEvent e) {
handleAction(e);
}
});
JRadioButton saveButton = new JRadioButton("Save");
saveButton.addKeyListener(new KeyListener() {
@Override
public void keyReleased(KeyEvent e) {
handleAction(e);
}
@Override
public void keyTyped(KeyEvent e) {
}
@Override
public void keyPressed(KeyEvent e) {
handleAction(e);
}
});
saveButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
handleAction(e);
}
public void actionEvent(ActionEvent e) {
handleAction(e);
}
});
JRadioButton wireButton = new JRadioButton("Wiring");
wireButton.setMnemonic(KeyEvent.VK_W);
wireButton.addKeyListener(new KeyListener() {
@Override
public void keyReleased(KeyEvent e) {
handleAction(e);
}
@Override
public void keyTyped(KeyEvent e) {
}
@Override
public void keyPressed(KeyEvent e) {
handleAction(e);
}
});
wireButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
handleAction(e);
}
public void actionEvent(ActionEvent e) {
handleAction(e);
}
});
JRadioButton subcircuitButton = new JRadioButton("Subcircuit");
subcircuitButton.setMnemonic(KeyEvent.VK_C);
subcircuitButton.addKeyListener(new KeyListener() {
@Override
public void keyReleased(KeyEvent e) {
handleAction(e);
}
@Override
public void keyTyped(KeyEvent e) {
}
@Override
public void keyPressed(KeyEvent e) {
handleAction(e);
}
});
subcircuitButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
handleAction(e);
}
public void actionEvent(ActionEvent e) {
handleAction(e);
}
});
JRadioButton ANDButton = new JRadioButton("AND Gate");
ANDButton.setMnemonic(KeyEvent.VK_A);
ANDButton.addKeyListener(new KeyListener() {
@Override
public void keyReleased(KeyEvent e) {
handleAction(e);
}
@Override
public void keyTyped(KeyEvent e) {
}
@Override
public void keyPressed(KeyEvent e) {
handleAction(e);
}
});
ANDButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
handleAction(e);
}
public void actionEvent(ActionEvent e) {
handleAction(e);
}
});
JRadioButton NANDButton = new JRadioButton("NAND Gate");
NANDButton.setMnemonic(KeyEvent.VK_N);
NANDButton.addKeyListener(new KeyListener() {
@Override
public void keyReleased(KeyEvent e) {
handleAction(e);
}
@Override
public void keyTyped(KeyEvent e) {
}
@Override
public void keyPressed(KeyEvent e) {
handleAction(e);
}
});
NANDButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
handleAction(e);
}
public void actionEvent(ActionEvent e) {
handleAction(e);
}
});
JRadioButton ORButton = new JRadioButton("OR Gate");
ORButton.addKeyListener(new KeyListener() {
@Override
public void keyReleased(KeyEvent e) {
handleAction(e);
}
@Override
public void keyTyped(KeyEvent e) {
}
@Override
public void keyPressed(KeyEvent e) {
handleAction(e);
}
});
ORButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
handleAction(e);
}
public void actionEvent(ActionEvent e) {
handleAction(e);
}
});
JRadioButton groundButton = new JRadioButton("Ground");
groundButton.addKeyListener(new KeyListener() {
@Override
public void keyReleased(KeyEvent e) {
handleAction(e);
}
@Override
public void keyTyped(KeyEvent e) {
}
@Override
public void keyPressed(KeyEvent e) {
handleAction(e);
}
});
groundButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
handleAction(e);
}
public void actionEvent(ActionEvent e) {
handleAction(e);
}
});
JRadioButton powerButton = new JRadioButton("Power");
powerButton.addKeyListener(new KeyListener() {
@Override
public void keyReleased(KeyEvent e) {
handleAction(e);
}
@Override
public void keyTyped(KeyEvent e) {
}
@Override
public void keyPressed(KeyEvent e) {
handleAction(e);
}
});
powerButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
handleAction(e);
}
public void actionEvent(ActionEvent e) {
handleAction(e);
}
});
ButtonGroup group = new ButtonGroup();
group.add(selectButton);
group.add(removeButton);
group.add(openButton);
group.add(saveButton);
group.add(wireButton);
group.add(subcircuitButton);
group.add(ANDButton);
group.add(NANDButton);
group.add(ORButton);
group.add(groundButton);
group.add(powerButton);
//menu buttons, still need more features and zoom/move simulation screen
add(selectButton);
add(removeButton);
add(openButton);
add(saveButton);
add(wireButton);
add(subcircuitButton);
add(ANDButton);
add(NANDButton);
add(ORButton);
add(groundButton);
add(powerButton);
selectButton.setBounds((int)(Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (1.0/11.0)), 50, 0, 0); //11 is number of buttons as far as now
removeButton.setBounds((int)(Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (1.0/11.0)), 50, (int) (Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (1.0/11.0)), 0);
openButton.setBounds((int)(Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (1.0/11.0)), 50, (int) (Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (2.0/11.0)), 0);
saveButton.setBounds((int)(Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (1.0/11.0)), 50, (int) (Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (3.0/11.0)), 0);
wireButton.setBounds((int)(Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (1.0/11.0)), 50, (int) (Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (4.0/11.0)), 0);
subcircuitButton.setBounds((int)(Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (1.0/11.0)), 50, (int) (Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (5.0/11.0)), 0);
ANDButton.setBounds((int)(Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (1/11)), 50, (int) (Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (6.0/11.0)), 0);
NANDButton.setBounds((int)(Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (1.0/11.0)), 50, (int) (Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (7.0/11.0)), 0);
ORButton.setBounds((int)(Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (1.0/11.0)), 50, (int) (Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (8.0/11.0)), 0);
groundButton.setBounds((int)(Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (1.0/11.0)), 50, (int) (Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (9.0/11.0)), 0);
powerButton.setBounds((int)(Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (1.0/11.0)), 50, (int) (Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (10.0/11.0)), 0);
//subcircuit buttons
JScrollPane ScrollPane = new JScrollPane();
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(null);
buttonPanel.setSize(new Dimension((int) (Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (1/5)), (int) (Toolkit.getDefaultToolkit().getScreenSize().getHeight() - 50)));
ScrollPane.setViewportView(buttonPanel);
add(ScrollPane);
ScrollPane.setBounds((int) (Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (1/5)), (int) (Toolkit.getDefaultToolkit().getScreenSize().getHeight() - 50), 0, 50);
ScrollPane.updateUI();
blankArea = new BlankArea(Color.WHITE);
add(blankArea);
blankArea.addMouseListener(this);
blankArea.addMouseMotionListener(this);
blankArea.setBounds((int) (Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (4/5)), (int) (Toolkit.getDefaultToolkit().getScreenSize().getHeight() - 50), (int) (Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (1/5)), 50);
addMouseListener(this);
addMouseMotionListener(this);
setPreferredSize(new Dimension((int) (Toolkit.getDefaultToolkit().getScreenSize().getWidth() * (4/5)),(int) (Toolkit.getDefaultToolkit().getScreenSize().getHeight() - 50)));
}
public void handleAction(KeyEvent e) {
if ((e.getModifiers() & KeyEvent.CTRL_MASK) != 0 && (e.getKeyChar() == 'S' || e.getKeyChar() == 's')) {
try {
//saveCurrentFile();
} catch(Exception ex) {
JOptionPane.showMessageDialog(frame, ex.getStackTrace());
}
} else if ((e.getModifiers() & KeyEvent.CTRL_MASK) != 0 && (e.getKeyChar() == 'O' || e.getKeyChar() == 'o')) {
try {
//openFile();
} catch(Exception ex) {
JOptionPane.showMessageDialog(frame, ex.getStackTrace());
}
} else if ((e.getModifiers() & KeyEvent.CTRL_MASK) == 0 && (e.getKeyChar() == 'A' || e.getKeyChar() == 'a')) {
//selectAll();
} else if ((e.getModifiers() & KeyEvent.CTRL_MASK) == 0 && (e.getKeyChar() == 'A' || e.getKeyChar() == 'a')) {
} else if ((e.getModifiers() & KeyEvent.CTRL_MASK) == 0 && (e.getKeyChar() == 'N' || e.getKeyChar() == 'n')) {
} else if ((e.getModifiers() & KeyEvent.CTRL_MASK) == 0 && (e.getKeyChar() == 'O' || e.getKeyChar() == 'o')) {
}
}
public void handleAction(ActionEvent e) {
if (e.getActionCommand() == "Save") {
try {
//saveCurrentFile();
} catch(Exception ex) {
JOptionPane.showMessageDialog(frame, ex.getStackTrace());
}
} else if (e.getActionCommand() == "Open") {
try {
//openFile();
} catch(Exception ex) {
JOptionPane.showMessageDialog(frame, ex.getStackTrace());
}
} else if (e.getActionCommand() == "AND Gate") {
} else if (e.getActionCommand() == "NAND Gate") {
} else if (e.getActionCommand() == "OR Gate") {
} else if (e.getActionCommand() == "Select") {
} else if (e.getActionCommand() == "Ground") {
} else if (e.getActionCommand() == "Power") {
} else if (e.getActionCommand() == "Remove") {
} else if (e.getActionCommand() == "Subcircuit") {
} else if (e.getActionCommand() == "Wiring") {
}
}
public void mousePressed(MouseEvent e) {
}
public void mouseReleased(MouseEvent e) {
}
public void mouseEntered(MouseEvent e) {
}
public void mouseExited(MouseEvent e) {
}
public void mouseClicked(MouseEvent e) {
}
public void mouseMoved(MouseEvent e) {
}
public void mouseDragged(MouseEvent e) {
}
}
【问题讨论】：
-
第 1 步：不要使用空布局。
-
您将每个按钮的高度设置为 0，将滚动窗格的宽度以及
selectButton设置为 0。 -
我同意@gla3dr 的观点，认为
null布局是创建复杂GUI 的最简单方法，这是在自欺欺人。但是，它们的问题是它们的使用导致了很难增强或调试的刚性 GUI，在大多数平台上看起来很糟糕的 GUI，除了可能是一个。更好的长期解决方案是学习和使用布局管理器，学习嵌套 JPanel，每个 JPanel 都使用自己的布局管理器。 -
"I think its simplest for now"-- 但这会延迟你学习使用布局管理器的时间，这是你不应该做的事情。勇敢——冒险——学习布局。 -
“你们会批评我吗？” 人们不是在批评你，只是在代码方法。不要将自己与您的代码混淆。 “或者你会帮我解决我的空布局吗？”如果你所说的“帮助”是指引导你找到一个不会导致多 3-4 个的解决方案 '现在我该如何解决...？' 风格的问题，是的。但要做到这一点，我们会使用布局，您似乎甚至拒绝向我们提供足够的信息来帮助您。
标签： java swing layout-manager null-layout-manager