如何对齐按钮

Question

Buttons are lying horizontally one after the other. I need to know how to make them appear on the screen vertically. I tried adding SwingConstants.xxxx. Then item.SwingConstants.xxx got the horizontal alignment error. Any help is appreciated. (want to stick to this style of program)

import java.awt. * ;
import java.awt.event. * ;
import javax.swing. * ;

@SuppressWarnings("serial")
public class Class_GUI_4 extends JFrame {
  private JTextField tf; // textfield
  private JCheckBox b1; // button 1
  private JCheckBox b2; // button2
  public Class_GUI_4() {
    super("TITLE");
    setLayout(new FlowLayout());

    tf = new JTextField("A testing Sentence", 20);
    tf.setFont(new Font("Serif", Font.PLAIN, 14));
    add(tf);

    b1 = new JCheckBox("Bold");
    b2 = new JCheckBox("Italic");
    add(b1);
    add(b2);

    thehandler handler = new thehandler();
    b1.addItemListener(handler);
    b2.addItemListener(handler);
  }

  private class thehandler implements ItemListener {
    @Override
    public void itemStateChanged(ItemEvent event) {
      Font font = null;
      if (b1.isSelected() && b2.isSelected()) font = new Font("Serif", Font.BOLD + Font.ITALIC, 14);
      else if (b1.isSelected()) font = new Font("Serif", Font.BOLD, 14);
      else if (b2.isSelected()) font = new Font("Serif", Font.ITALIC, 14);
      else font = new Font("Serif", Font.PLAIN, 14);
      tf.setFont(font);
    }
  }

  public static void main(String[] args) {
    Class_GUI_4 gui = new Class_GUI_4();
    gui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    gui.setSize(200, 350);
    gui.setVisible(true);
  }
}

Answer 1

how to make them come on screen vertically?

Try with BoxLayout

setLayout(new BoxLayout(getContentPane(), BoxLayout.PAGE_AXIS));

instead of FlowLayout in this case that arranges components in a directional flow, much like lines of text in a paragraph.

setLayout(new FlowLayout());

It's worth reading about How to Use BoxLayout

---

Don't use GridLayout in this case that adds the components in equal size as shown below:

---

Instead you can try with GridBagLayout . Read more about How to Use GridBagLayout

Sample code: (Change the height as per your requirement in percentage)

setLayout(new GridBagLayout());
GridBagConstraints gc = new GridBagConstraints();
gc.fill = GridBagConstraints.BOTH;

//Set the margin between components top, left, bottom, right
//gc.insets=new Insets(5, 5, 5, 5);

tf = new JTextField("A testing Sentence", 20);
tf.setFont(new Font("Serif", Font.PLAIN, 14));

gc.gridx = 0; // 1st row
gc.gridy = 0; // 1st column
gc.weighty = 0.9; // 90%
add(tf, gc);

b1 = new JCheckBox("Bold");
b2 = new JCheckBox("Italic");
gc.gridy = 1; // 2nd column
gc.weighty = 0.05;// 5%
add(b1, gc);

gc.gridy = 2; // 3rd column
gc.weighty = 0.05;// 5%
add(b2, gc);

Answer 2

您必须使用布局管理器来格式化您的 UI 组件，您可以在有助于您进行垂直对齐的布局之间进行选择，即网格布局或框布局。

Answer 3

This is because the layout manager you are using is FlowLayout().

    setLayout(new FlowLayout());

Use GridLayout manager instead by replacing the code with:

    setLayout(new GridLayout(1,3)