java - 如何使用 GridBagLayout 对齐 JPanel 中的组件中心？

Question

当我尝试对齐我的组件时，它会向左或向右对齐。

所以我只想解决这个问题，并告诉我如何将面板的大小设置为 400 x 350 像素。

这是我的代码....titleLabel 和ResultLabel 应该居中对齐

public TimeGui() {

    layout = new GridBagLayout();
    setSize(400, 350);  //**Its not working**
    setBackground(Color.LIGHT_GRAY);
    setBorder(BorderFactory.createLineBorder(Color.BLACK));
    setBorder(new TitledBorder(new EtchedBorder(), "Time Conversion") );

    setLayout(layout);
    layoutConstraints = new GridBagConstraints();       
    textField1 = new JTextField(10);
    textField2 = new JTextField(10);

    String[] names1 = {"Seconds", "Minutes", "Hours", "Days", "Weeks"};


    comboBox1 = new JComboBox<>(names1);
    comboBox2 = new JComboBox<>(names1);

    titleLabel = new JLabel("Time Conversion Unit", JLabel.CENTER);
    resultLabel = new JLabel("Result Label");
    equalLabel = new JLabel("=");

    convertButton = new JButton("Convert");


    layoutConstraints.fill = GridBagConstraints.HORIZONTAL;
    Insets inset = new Insets(10, 10, 10, 10);
    layoutConstraints.anchor = GridBagConstraints.CENTER;

    addComponent(titleLabel, 0, 0, 2, 2, inset ); // I tried (0,1,2,2) 



    addComponent(comboBox1, 3, 0, 2, 3, inset);

    addComponent(comboBox2, 3, 2, 2, 3, inset);

    addComponent(textField1, 6, 0, 1, 2, inset);

    addComponent(equalLabel, 6, 1, 1, 2, inset);

    addComponent(textField2, 6, 2, 1, 2, inset);

    addComponent(resultLabel, 8, 1, 2, 1, inset);

    addComponent(convertButton, 10, 0, 2, 2, inset);

}

private void addComponent(Component component, int row,
        int column, int width, int height, Insets inset1) {
    layoutConstraints.gridx = column;
    layoutConstraints.gridy = row;
    layoutConstraints.gridwidth = width;
    layoutConstraints.gridheight = height;
    layoutConstraints.insets = inset1;
    layout.setConstraints(component, layoutConstraints);
    add(component);
}
}

Answer 1

问题出在您的 gridwidth 和 fill 属性上...

基本上我所做的改变是...

addComponent(titleLabel, 0, 0, GridBagConstraints.REMAINDER, 2, inset); // I tried (0,1,2,2) 
addComponent(comboBox1, 3, 0, 1, 3, inset);
addComponent(comboBox2, 3, 2, 1, 3, inset);
addComponent(textField1, 6, 0, 1, 2, inset);
addComponent(equalLabel, 6, 1, 1, 2, inset);
addComponent(textField2, 6, 2, 1, 2, inset);
layoutConstraints.fill = GridBagConstraints.NONE;
addComponent(resultLabel, 8, 0, GridBagConstraints.REMAINDER, 1, inset);
addComponent(convertButton, 10, 0, GridBagConstraints.REMAINDER, 2, inset);

你可以和其他几个一起玩。

至于定义面板的实际大小，你能做的最好的事情就是覆盖 TimeGui 的 getPreferredSize 方法...

@Override
public Dimension getPreferredSize() {
    return new Dimension(400, 350);
}

这将向父容器“建议”您希望布局的大小。请记住，这是一个可选值，布局管理员完全有权忽略它。