Java摇摆 | ScrollPaneLayout 类

JScrollPane 使用的布局管理器。 JScrollPaneLayout基于九个组件：一个视口、两个滚动条、一个行标题、一个列标题和四个“角”组件。

类的构造函数：

• ScrollPaneLayout()：用于构造一个新的ScrollPanelLayout。

常用方法：

1. removeLayoutComponent(Component comp)：从布局中移除指定的组件。
2. getColumnHeader()：它返回作为列标题的 JViewport 对象。
3. getVerticalScrollBar()：返回处理垂直滚动的 JScrollBar 对象。
4. getHorizontalScrollBar()：返回处理水平滚动的 JScrollBar 对象。
5. addLayoutComponent(String st, Component c)：将指定组件添加到布局中。
6. getViewport()：返回显示可滚动内容的 JViewport 对象。
7. getCorner(String key)：用于返回指定角的Component。

下面的程序说明了 ScrollPanelLayout 类的使用：

1. 下面的程序通过在一个实例类为“ Geeks ”的JFrame中排列几个JLabel组件来说明 ScrollPaneLayout 的使用。我们创建一个名为“ scrollpane ”的JScrollPane组件和一个名为“ list ”的JList组件。我们使用setSize()和setVisible()方法设置框架的大小和可见性。使用setLayout()方法设置布局。

Java

// Java Program to illustrate the
// ScrollPaneLayout class
import java.awt.BorderLayout;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JScrollPane;
 
// create a class Geeks extending JFrame
public class Geeks extends JFrame
 
{
     
    // Declaration of objects of the
    // JScrollPane class.
    JScrollPane scrollpane;
 
    // Constructor of Geeks class
    public Geeks()
    {
         
        // used to call super class
        // variables and methods
        super("JScrollPane Demonstration");
 
        // Function to set size of JFrame.
        setSize(300, 200);
 
        // Function to set Default close
        // operation of JFrame.
        setDefaultCloseOperation(EXIT_ON_CLOSE);
 
        // to contain a string value
        String categories[] = {"Geeks", "Language", "Java",
                               "Sudo Placement", "Python",
                               "CS Subject", "Operating System",
                               "Data Structure", "Algorithm",
                               "PHP language", "JAVASCRIPT",
                               "C Sharp" };
 
        // Creating Object of "JList" class
        JList list = new JList(categories);
 
        // Creating Object of
        // "scrollpane" class
        scrollpane = new JScrollPane(list);
 
        // to get content pane
        getContentPane().add(scrollpane, BorderLayout.CENTER);
    }
 
    // Main Method
    public static void main(String args[])
    {
         
        // Creating Object of Geeks class.
        Geeks sl = new Geeks();
 
        // Function to set visibility of JFrame.
        sl.setVisible(true);
    }
}

输出：

2. 下面的程序通过在一个JFrame中排列几个JLabel组件来说明ScrollPaneLayout的使用，它的实例类被命名为“ ScrollPanel ”。我们创建了一个名为“ scrollpane ”的JScrollPane组件。此外，还创建了JRadioButton和ButtonGroup 。我们使用setSize()和setVisible()方法设置框架的大小和可见性。使用setLayout()方法设置布局。

Java

// Java Program to illustrate the
// ScrollPaneLayout class
import java.awt.BorderLayout;
import java.awt.GridLayout;
import javax.swing.ButtonGroup;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JScrollPane;
 
// create a class ScrollPanel
// extending JFrame
public class ScrollPanel extends JFrame {
 
    // Declaration of objects of the
    // JScrollPane class
    JScrollPane scrollpane;
 
    // Constructor of ScrollPanel class
    public ScrollPanel()
    {
         
        // used to call super class
        // variables and methods
        super("JScrollPane Demonstration");
 
        // Function to set size of JFrame.
        setSize(300, 200);
 
        // Function to set Default
        // close operation of JFrame.
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        init();
 
        // Function to set
        // visible of JFrame.
        setVisible(true);
    }
     
    // class init
    public void init()
    {
         
        // Declaration of objects
        // of JRadioButton class.
        JRadioButton form[][] = new JRadioButton[12][5];
 
        // to contain a string count
        String counts[] = {"", "1 star", "2 star",
                    "3 star", "4 star", "5 star"};
 
        // to contain a string value
        String categories[] = {"Geeks", "Language", "Java",
                               "Sudo Placement", "Python",
                               "CS Subject", "Operating System",
                               "Data Structure", "Algorithm",
                               "PHP language", "JAVASCRIPT",
                               "C Sharp" };
 
        // Declaration of objects
        // of the JPanel class.
        JPanel p = new JPanel();
 
        // Function to set size of JFrame.
        p.setSize(600, 400);
 
        // Function to set Layout of JFrame.
        p.setLayout(new GridLayout(13, 6, 10, 0));
 
        // for loop
        for (int row = 0; row < 13; row++) {
             
            // Declaration of objects
            // of ButtonGroup class
            ButtonGroup bg = new ButtonGroup();
 
            for (int col = 0; col < 6; col++)
            {
                 
                // If condition
                if (row == 0) {
 
                    // add new Jlabel
                    p.add(new JLabel(counts[col]));
                }
                else {
                    // If condition
                    if (col == 0)
                    {
 
                        // add new Jlabel
                        p.add(new JLabel(categories[row - 1]));
                    }
                     
                    else
                    {
                        form[row - 1][col - 1] = new JRadioButton();
 
                        // add form in ButtonGroup
                        bg.add(form[row - 1][col - 1]);
 
                        // add form in JFrame
                        p.add(form[row - 1][col - 1]);
                    }
                }
            }
        }
 
        // Declaration of objects
        // of scrollpane class.
        scrollpane = new JScrollPane(p);
 
        // to get content pane
        getContentPane().add(scrollpane, BorderLayout.CENTER);
    }
 
    // Main Method
    public static void main(String args[])
    {
        new ScrollPanel();
    }
}

输出：

注意：上述程序可能无法在在线 IDE 中运行。请使用离线编译器。

参考： https://docs.oracle.com/javase/7/docs/api/javax/swing/ScrollPaneLayout.html