【Java AWT 图形界面编程】Frame 窗口标题栏大小问题 ( Container 容器的空白边框 Insets | 通过调用 frame.getInsets().top 获取窗口标题栏高度 )

        // 绘制左上角布局
        Panel panel1 = new Panel();
        panel1.setBackground(Color.BLUE);
        panel1.setBounds(0, 0, 100, 100);
        frame.add(panel1);

        // 绘制右上角布局
        Panel panel2 = new Panel();
        panel2.setBackground(Color.RED);
        panel2.setBounds(200, 0, 100, 100);
        frame.add(panel2);

    /**
     * Determines the insets of this container, which indicate the size
     * of the container's border.
     * <p>
     * A <code>Frame</code> object, for example, has a top inset that
     * corresponds to the height of the frame's title bar.
     * @return    the insets of this container.
     * @see       Insets
     * @see       LayoutManager
     * @since     JDK1.1
     */
    public Insets getInsets() {
        return insets();
    }

package java.awt;

/**
 * An <code>Insets</code> object is a representation of the borders
 * of a container. It specifies the space that a container must leave
 * at each of its edges. The space can be a border, a blank space, or
 * a title.
 * <code>Insets</code>对象表示容器的边框。它指定了容器在每条边上必须保留的空间。
 * 空格可以是边框、空格或标题。
 *
 * @author      Arthur van Hoff
 * @author      Sami Shaio
 * @see         java.awt.LayoutManager
 * @see         java.awt.Container
 * @since       JDK1.0
 */
public class Insets implements Cloneable, java.io.Serializable {

    /**
     * The inset from the top.
     * This value is added to the Top of the rectangle
     * to yield a new location for the Top.
     * 从上到下的插图。
     * 该值被添加到矩形的Top以生成Top的新位置。
     *
     * @serial
     * @see #clone()
     */
    public int top;

    /**
     * The inset from the left.
     * This value is added to the Left of the rectangle
     * to yield a new location for the Left edge.
     *
     * @serial
     * @see #clone()
     */
    public int left;

    /**
     * The inset from the bottom.
     * This value is subtracted from the Bottom of the rectangle
     * to yield a new location for the Bottom.
     *
     * @serial
     * @see #clone()
     */
    public int bottom;

    /**
     * The inset from the right.
     * This value is subtracted from the Right of the rectangle
     * to yield a new location for the Right edge.
     *
     * @serial
     * @see #clone()
     */
    public int right;
}

import java.awt.*;

public class HelloAWT {
    public static void main(String[] args) {
        Frame frame = new Frame("AWT 界面编程");
        frame.setVisible(true);

        Insets insets = frame.getInsets();
        System.out.println(insets);
        System.out.println("Frame 窗口标题栏高度 : " + insets.top);
    }
}

java.awt.Insets[top=31,left=8,bottom=8,right=8]
Frame 窗口标题栏高度 : 31

import java.awt.*;

public class HelloAWT {
    public static void main(String[] args) {
        // Frame 默认的布局管理器就是 BorderLayout
        Frame frame = new Frame("AWT 界面编程");
        // 如果想要自己控制布局, 则取消 Frame 窗口的布局管理器
        frame.setLayout(null);

        // 自动设置 Frame 窗口合适的大小
        frame.setBounds(0, 0, 300, 331);

        // 设置 5 个布局, 分别在 4 个角和 中心位置显示

        // 绘制左上角布局
        Panel panel1 = new Panel();
        panel1.setBackground(Color.BLUE);
        panel1.setBounds(0, 31, 100, 100);
        frame.add(panel1);

        // 绘制右上角布局
        Panel panel2 = new Panel();
        panel2.setBackground(Color.RED);
        panel2.setBounds(200, 31, 100, 100);
        frame.add(panel2);

        // 绘制左下角布局
        Panel panel3 = new Panel();
        panel3.setBackground(Color.BLACK);
        panel3.setBounds(0, 231, 100, 100);
        frame.add(panel3);

        // 绘制右下角布局
        Panel panel4 = new Panel();
        panel4.setBackground(Color.GREEN);
        panel4.setBounds(200, 231, 100, 100);
        frame.add(panel4);

        // 绘制中间布局
        Panel panel5 = new Panel();
        panel5.setBackground(Color.MAGENTA);
        panel5.setBounds(100, 131, 100, 100);
        frame.add(panel5);

        frame.setVisible(true);

        Insets insets = frame.getInsets();
        System.out.println(insets);
    }
}

java.awt.Insets[top=31,left=8,bottom=8,right=8]