为什么JPanel没有在我的应用程序中的所有行？

Question

我的JPanel应该包含300行文本，但不管我做什么来扩大它的大小，它不会包含所有300行文本，为什么以及如何修复？这里是我的代码：

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

public class My_Chart_Panel extends JPanel 
{ 
    String Label_Text="      -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10"; 
    Vector<String> String_Vector=new Vector(); 
    Font Times_New_Roman_15_Font=new Font("Times New Roman",0,15); 

    My_Chart_Panel() 
    { 
    for (int i=0;i<300;i++) String_Vector.add("Line : "+(i+1)); 
    JScrollPane Chart_ScrollPane=new JScrollPane(new A_Chart_Panel(String_Vector)); 
    Chart_ScrollPane.setPreferredSize(new Dimension(536,770)); 
    Chart_ScrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER); 
    Chart_ScrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED); 

    JPanel Top_Panel=new JPanel(); 
    JLabel Top_Label=new JLabel(Label_Text); 
    Top_Label.setForeground(new Color(0,50,160)); 
    Top_Label.setFont(Times_New_Roman_15_Font); 
    Top_Panel.add(Top_Label); 
    add("North",Top_Panel); 

    add("Center",Chart_ScrollPane); 
    JPanel Bottom_Panel=new JPanel(); 
    JLabel Bottom_Label=new JLabel(Label_Text); 
    Bottom_Label.setForeground(new Color(0,50,160)); 
    Bottom_Label.setFont(Times_New_Roman_15_Font); 
    Bottom_Panel.add(Bottom_Label); 
    add("South",Bottom_Panel); 

    setPreferredSize(new Dimension(536,900)); 
    } 

    public static void main(String[] args) 
    { 
    JFrame f=new JFrame("My_Chart_Panel"); 
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    f.add(new My_Chart_Panel()); 
    f.setSize(560,910); 
    f.setLocationRelativeTo(null); 
    f.setVisible(true); 
    } 
} 

class A_Chart_Panel extends JPanel 
{ 
    Vector<String> String_Vector; 
    final int PAD=2; 

    A_Chart_Panel(Vector<String> String_Vector) 
    { 
    this.String_Vector=String_Vector; 
    setPreferredSize(new Dimension(530,String_Vector.size()*8)); 
    Draw_Chart(); 
    } 

    void Draw_Chart() 
    { 
    Out("String_Vector.size() = "+String_Vector.size()); 
    } 

    protected void paintComponent(Graphics g) 
    { 
    super.paintComponent(g); 
    Graphics2D g2=(Graphics2D) g; 
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON); 
    int w=getWidth(); 
    int h=getHeight(); 
    g2.drawLine(PAD+w*9/15,PAD,PAD+w*9/15,h-PAD); 
    g2.drawLine(PAD+w*9/15,PAD,PAD+w*9/15-5,PAD+26); 
    g2.drawLine(PAD+w*9/15,PAD,PAD+w*9/15+5,PAD+26); 

    double xScale=(w-2*PAD)/(20); 
    double maxValue=100.0; 
    double yScale =(h-2*PAD)/maxValue; 
    // The origin location. 
    int x0=PAD; 
    int y0=h-PAD; 
    g2.setPaint(Color.BLUE); 
    for (int j=0;j<String_Vector.size();j++) 
    { 
     int x=x0+(int)(xScale*(j+1)); 
     int y=20+(int)(yScale*j); 
     g2.drawString(String_Vector.elementAt(j),5,y); 
    } 
    } 

    private static void out(String message) { System.out.print(message); } 
    private static void Out(String message) { System.out.println(message); } 
} 

Answer 1

我想通了，这里就是答案：

class A_Chart_Panel extends JPanel 
{ 
    Vector<String> String_Vector; 
    final int PAD=2; 

    A_Chart_Panel(Vector<String> String_Vector) 
    { 
    this.String_Vector=String_Vector; 
    setPreferredSize(new Dimension(530,String_Vector.size()*12)); 
    Draw_Chart(); 
    } 

    void Draw_Chart() 
    { 
    Out("String_Vector.size() = "+String_Vector.size()); 
    } 

    protected void paintComponent(Graphics g) 
    { 
    super.paintComponent(g); 
    Graphics2D g2=(Graphics2D) g; 
    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON); 
    int w=getWidth(); 
    int h=getHeight(); 
    g2.drawLine(PAD+w*9/15,PAD,PAD+w*9/15,h-PAD); 
    g2.drawLine(PAD+w*9/15,PAD,PAD+w*9/15-5,PAD+26); 
    g2.drawLine(PAD+w*9/15,PAD,PAD+w*9/15+5,PAD+26); 

    double xScale=(w-2*PAD)/(20); 
    double maxValue=String_Vector.size(); 
    double yScale =(h-2*PAD)/maxValue; 
    // The origin location. 
    int x0=PAD; 
    int y0=h-PAD; 
    g2.setPaint(Color.BLUE); 
    for (int j=0;j<String_Vector.size();j++) 
    { 
     int x=x0+(int)(xScale*(j+1)); 
     int y=10+(int)(yScale*j); 
     g2.drawString(String_Vector.elementAt(j),5,y); 
    } 
    }