我有一个 JApplet，它必须显示 3 个组件.(2 JPanels 和 1 Paint Method) [英] I have a JApplet which has to display 3 Components. (2 JPanels and 1 Paint Method)
本文介绍了我有一个 JApplet，它必须显示 3 个组件.(2 JPanels 和 1 Paint Method)的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有一项作业，我必须允许用户使用二次方程绘制图形.
I have an assignment in which I have to allow a user to plot a graph using a quadratic equation.
我设法绘制了图形的骨架，现在我正在尝试显示控制面板"供用户输入值.
I managed to draw the skeleton of the graph, and now I am trying to display the "control panel" for the user to input the values.
我有 4 个文件:
graph.javapanel.javapanelB.javapanelC.java
我的问题是当我运行代码时它只显示 panel.java 即使在它应该显示其他两个面板的容器中也是如此.
My problem is when I run the code it is displaying only the panel.java even in the container where it should display the other two panels.
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.*;
import java.awt.geom.*;
import javax.swing.JPanel;
public class panel extends JPanel {
public panel(){
this.setBackground(Color.yellow);
}
}
谁能建议我应该做哪些更改来解决这个问题?
Can anyone please advise what changes I should do to fix this problem?
我对 graph.java 文件做了一些更改:
I have done some changes to the graph.java file:
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Dimension;
import javax.swing.*;
public class GraphApplet extends JApplet{
public GraphApplet(){
raph p = new Graph();//graph
p.setPreferredSize(new Dimension(760,500));
conn.add(p,BorderLayout.CENTER);
}
现在显示的只是图表.
关于其他代码，我也对类名进行了一些更改:
Regarding the other code, I also made some changes to the class names:
gnjk;.java
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.*;
import java.awt.geom.*;
import javax.swing.JPanel;
public class Graph extends JPanel {
public Graph(){
this.setBackground(Color.yellow);
}
public void paintComponent(Graphics p) {
super.paintComponent(p);
Graphics2D graph = (Graphics2D)p;
this.setBackground(Color.yellow);//set background color.
int x,y,y1,x1,a,b,p1x,p1y,p2x,p2y;
int xstart = 7;
int ystart = 1;
int xfinish = 3;
.......
bhfvhn.java
import javax.swing.*;
import java.awt.*;
import javax.swing.JPanel;
public class ControlsA extends JPanel{
public void init (Box g) {
a = Box.createVerticalBox();
a.add(new JLabel("Please enter the values below:"));
a.add(new JLabel("h"));
}
}
jknmk.java
import javax.swing.*;
import java.awt.Component;
import java.awt.Dimension;
public class ControlsB extends JPanel{
public void init (Box b) {
b = Box.createHorizontalBox();
b.add(new JLabel("a"));
JTextField f1 = new JTextField("0.0");
f1.setMaximumSize(new Dimension(100,30));
b.add(f1);
}
}
这是我的项目的更新:
Here is an updated to my project:
jkl.java
import java.awt.BorderLayout;
import java.awt.Container;
public class GraphApplet extends JApplet{
public GraphApplet() {
public void init(){
SwingUtilities.invokeLater(new Runnable() {
public void run(){
Container conn = getContentPane();
conn.setLayout(new BorderLayout());
Graph z = new Graph();
conn.add(p,BorderLayout.CENTER);
fasfae a = new ControlsA(box1);
conn.add(a,BorderLayout.LINE_START);
adsfawef b = new ControlsB(box2);
conn.add(b,BorderLayout.PAGE_END);
}
});
}
}
/*Container conn = getContentPane();
conn.setLayout(new BorderLayout());
Graph p = new Graph();//graph
p.setPreferredSize(new Dimension(460,560));
conn.add(p,BorderLayout.CENTER);
Box a = new Box(BoxLayout.Y_AXIS);
a.setPreferredSize(new Dimension(50,50));
conn.add(a,BorderLayout.EAST);
Box b = new Box(BoxLayout.X_AXIS);
b.setPreferredSize(new Dimension(201,50));
conn.add(b,BorderLayout.SOUTH);*/
//this code is commented not to loose it
vtk.java
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.*;
import java.awt.geom.*;
import javax.swing.JPanel;
class Graph extends JPanel {
public Graph(){
this.setBackground(Color.yellow);
}
@Override
public Dimension getPreferredSize(){return (new Dimension(460,560)); }
public void paint(Graphics z) {
Graphics graph = (Graphics2D)z;
this.setBackground(Color.yellow).
int x,y,y1,x1,a,b,p1x,p1y,p2x,p2y;
//line co-ordinates
//the numbers represent the number of boxes on the graph
int xstart = 7;
int ystart = 1;
int x = 3;
int y = 9;
//other variables
int i = 0;
int i2 = 0;
int m = 0;
int n = 0;
int m2 = 0;
int n2 = 0;
int f2 = 0;
int g2 = 1;
//ranges
int f = 5;
int g = -5;
//change -ve num to +ve
int g3 = Math.abs(g);
int a1 = g3 + f;
int b1 = a1;
a = (Height);
f = (Width);
}
}
}
// 6 variables the user has to input
}
@Override
public Dimension getPreferredSize() {return (new Dimension(200,100));}
}
nllkl.java
@Override
public Dimension getPreferredSize(){return (new Dimension(201,50));}
}
仍然没有改善.我不明白发生了什么.
Still no improvement. I cannot understand what is going on.
推荐答案
请现在尝试运行此代码，告诉我这是否更接近您想要的?如果是这样，请告诉我，以便我可以删除我的答案.请注意我所做的更改:
Please try to run this code now, tell me is this closer to what you wanted ? if so do let me know, so that I can delete my answer. Do watch the changes I had done :
- 在您的
PanelC类中，我没有使用init()方法，而是制作了构造函数. - 在你的 Graph 类中
- 我已经删除了所有
setPreferredSizes(...)调用，而是我为每个覆盖了getPreferredSize()扩展JPanel的类.为此，请访问每个班级小组、小组 B 和小组C. - 最后，我更改了提供给
JPanel的 Dimension 值，这是去LEFT/LINE_START一侧，到一些可以被看见 - 最好的改变是使用 EDT - 事件调度线程，看起来像你真的不知道Swing 中的并发
- in your
PanelCclass, where instead of usinginit()method, I made the constructor. - Inside your Graph class< i had removed all
setPreferredSizes(...)calls, and instead I had overriddengetPreferredSize()for each Class extendingJPanel. For this visit each Class Panel, PanelB and PanelC. - Lastly I had changed the Dimension values supplied to the
JPanel, which is to go to theLEFT/LINE_STARTside, to something that can be seen - BEST CHANGE is the use of EDT - Event Dispatch Thread, seems like you really not aware of Concurrency in Swing
import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;
public class Graph extends JApplet{
public void init(){
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
Container conn = getContentPane();
conn.setLayout(new BorderLayout());
Panel p = new Panel();//graph
conn.add(p,BorderLayout.CENTER);
Box box1 = new Box(BoxLayout.Y_AXIS);
PanelB a = new PanelB(box1);//vertical
conn.add(a,BorderLayout.LINE_START);
Box box2 = new Box(BoxLayout.X_AXIS);
PanelC b = new PanelC(box2);//horizontal
conn.add(b,BorderLayout.PAGE_END);
}
});
}
}
class Panel extends JPanel {
public Panel(){
this.setBackground(Color.yellow);
}
@Override
public Dimension getPreferredSize()
{
return (new Dimension(460,560));
}
public void paintComponent(Graphics p) {
super.paintComponent(p);
Graphics2D graph = (Graphics2D)p;
Dimension appletSize = this.getSize();
int appletHeight = (int)(appletSize.height);
int appletWidth = appletSize.width;
this.setBackground(Color.yellow);//set background color.
int x,y,y1,x1,a,b,p1x,p1y,p2x,p2y;
//line co-ordinates
//the numbers represent the number of boxes on the graph
int xstart = 7;
int ystart = 1;
int xfinish = 3;
int yfinish = 9;
//other variables
int i = 0;
int i2 = 0;
int m = 0;
int n = 0;
int m2 = 0;
int n2 = 0;
int f2 = 0;
int g2 = 1;
//ranges
int f = 5;
int g = -5;
//change -ve num to +ve
int g3 = Math.abs(g);
int a1 = g3 + f;
int b1 = a1;
y1 = (appletHeight);
x1 = (appletWidth);
y = (appletHeight / 2);
x = (appletWidth / 2);
a = (appletWidth / a1);
b = (appletHeight / b1);
int d = (appletWidth / a1);
int e = (appletHeight / b1);
/**
to determine the
ammount of pixles there
is in each box of the
graph, both y-axis and
x-axis
*/
int xbox = x1 / 10;
int ybox = y1 / 10;
//line variables
//the xstart, ystart, etc represent the number of boxes
//top point of the line on the graph
p1x = xbox * xstart;//start x
p1y = ybox * ystart;//start y
//lowwer point of the line on the graph
p2x = xbox * xfinish;//finish x
p2y = ybox * yfinish;//finish y
//draw y-axis numbers
//(+ve)
while(f != 0){
String s = String.valueOf(f);
p.drawString(s,(x + 5),m + 13);
m = m + b;
f = f - 1;
}
//(-ve)
m2 = y;
while(f2 != g-1){
String u = String.valueOf(f2);
p.drawString(u,(x + 5),m2 - 3);
m2 = m2 + b;
f2 = f2 - 1;
}
//draw x-axis numbers.
//(-ve)
while(g != 0){
String t = String.valueOf(g);
p.drawString(t,n,y - 5);
n = n + a;
g = g + 1;
}
//(+ve)
n2 = x + a;
while(g2 != g3+1){
String vw = String.valueOf(g2);
p.drawString(vw,n2 -10,y - 5);
n2 = n2 + a;
g2 = g2 + 1;
}
BasicStroke aLine2 = new BasicStroke(1.0F,
BasicStroke.CAP_ROUND,BasicStroke.JOIN_ROUND);
graph.setStroke(aLine2);
//notch on numbers and grid lines
//left to right, top to bottom notches
int v2 = -5;
int v5 = 0;
while(i <= a1-1){
p.setColor(Color.lightGray);//lightgray line
p.drawLine(a,0,a,y1);//vertical lightgray
p.drawLine(0,b,x1,b);//horizontal lightgray
a = a + d;
b = b + e;
i = i + 1;
}
//notches
while(i2 <= a1){
p.setColor(Color.blue);//notch color
p.drawString("x",v2+2,y+3);//xaxis
p.drawString("x",x-4,v5+4);//yaxis
v5 = v5 + e;
v2 = v2 + d;
i2 = i2 + 1;
}
//draws the border of the graph
p.setColor(Color.black);
Rectangle2D.Float rect = new Rectangle2D.Float(0,0,x1,y1);
BasicStroke aLine = new BasicStroke(2.5F,
BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND);
graph.setStroke(aLine);
graph.draw(rect);
//draw cross
BasicStroke aLine3 = new BasicStroke(2.5F,
BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND);
graph.setStroke(aLine3);
p.drawLine(x,0,x,y1); //vertical line
p.drawLine(0,y,x1,y); //horizontal line
//display the value of graph width and graph height
String aw = String.valueOf(x1);
p.drawString("Graph Width = ", 50,90);
p.drawString(aw,150,90);
p.drawString("Graph Height = ", 50,110);
String ah = String.valueOf(y1);
p.drawString(ah,156,110);
//draw line on graph
BasicStroke aLine4 = new BasicStroke(1.5F,
BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND);
graph.setStroke(aLine4);
p.setColor(Color.red);
if(p1x <= x1 && p2x <= x1 && p1y <= y1 && p2y <= y1){
p.drawLine(p1x,p1y,p2x,p2y);
Color c = new Color(0,0,0);
p.setColor(c);
p.drawString("X", p1x-4,p1y+4);
p.drawString("X", p2x-4,p2y+4);
}
else{
p.setColor(Color.black);
p.drawRect(48,34,223,35);
p.setColor(Color.white);
p.fillRect(49,35,222,34);
p.setColor(Color.red);
p.drawString("Wrong co-ordinates!!!", 50,50);
p.drawString("Values exceede applet dimensions.", 50,65);
}
}
}
class PanelB extends JPanel{
public PanelB (Box a) {
a = Box.createVerticalBox();
a.add(new JLabel("Please enter the values below:"));
a.add(new JLabel("a"));
JTextField g1 = new JTextField("0.0");
g1.setMaximumSize(new Dimension(100,30));
a.add(g1);
a.add(new JLabel("b"));
JTextField g2 = new JTextField("0.0");
g2.setMaximumSize(new Dimension(100,30));
a.add(g2);
a.add(new JLabel("c"));
JTextField g3 = new JTextField("0.0");
g3.setMaximumSize(new Dimension(100,30));
a.add(g3);
a.add(new JLabel("d"));
JTextField g4 = new JTextField("0.0");
g4.setMaximumSize(new Dimension(100,30));
a.add(g4);
a.add(new JButton("Plot"));
a.add(new JButton("Refine"));
add(a);
}
@Override
public Dimension getPreferredSize()
{
return (new Dimension(200,100));
}
}
class PanelC extends JPanel{
public PanelC (Box b) {
b = Box.createHorizontalBox();
b.add(new JLabel("a"));
JTextField f1 = new JTextField("0.0");
f1.setMaximumSize(new Dimension(100,30));
b.add(f1);
b.add(new JLabel("b"));
JTextField f2 = new JTextField("0.0");
f2.setMaximumSize(new Dimension(100,30));
b.add(f2);
b.add(new JLabel("c"));
JTextField f3 = new JTextField("0.0");
f3.setMaximumSize(new Dimension(100,30));
b.add(f3);
b.add(new JLabel("d"));
JTextField f4 = new JTextField("0.0");
f4.setMaximumSize(new Dimension(100,30));
b.add(f4);
b.add(new JButton("Plot"));
b.add(new JButton("Refine"));
add(b);
}
@Override
public Dimension getPreferredSize()
{
return (new Dimension(201,50));
}
}
这是我使用的 HTML 文件:
Here is the HTML file I used :
<html>
<p> This file launches the 'Graph' applet: Graph.class! </p>
<applet code= "Graph.class" height = 550 width = 1000>
No Java?!
</applet>
</html>
这是我得到的输出:
这篇关于我有一个 JApplet，它必须显示 3 个组件.(2 JPanels 和 1 Paint Method)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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