【发布时间】:2014-11-05 17:03:45
【问题描述】:
我已经为图形绘制创建了一个 JPanel 子类,并将其添加到 Palette,但是当我尝试将它添加到主面板时没有任何反应。此外,如果我尝试将其添加为非调色板组件,对话框将关闭并再次重新打开,要求选择要添加的类。 这是课程:
import javax.swing.*;
import java.awt.*;
/**
* Created by gray on 05.11.14.
*/
public class PPanel extends JPanel {
// Object for the class realizing graph function
public Plotter G;
// Internal class for realization of graph function
class Plotter{
// rane of the coordinats
private double Xmin=0, Xmax=10.0, Ymin=0, Ymах= 120.0;
// graph line color:
private Color clr;
// grid line color:
private Color gclr;
// class constructor
Plotter(){
// read the text field and convert it into the number:
/* try{
Xmax=Double.valueOf(xmaxTF.getText());}
catch(NumberFormatException е){
xmaxTF.setText("10");
Xmax=10;}*/
// initializing grid line color:
gclr=Color.GRAY;
// initializing graph line color:
clr=Color.BLACK;
}
// the function that is being displayed:
private double f(double x){
return (3*Math.exp(0.4*x)); }
// methode for the grid display
public void plot(Graphics Fig){
// parameters for the range in which graph is being displayed
int H,W,h,w,s=20;
H=getHeight();
W=getWidth();
h=H-2*s;
w=W-2*s;
// clearing the graph
Fig.clearRect(0,0,W,H);
// index and quantity of grid lines
int k, nums=10;
Fig.setColor(Color.BLACK);
// coordinate axis:
Fig.drawLine(s,s,s,h+s);
Fig.drawLine(s,s+h,s+w,s+h);
for(k=0;k<=nums;k++){
Fig.drawLine(s+k*w/nums, s+h, s+k*w/nums, s+h+5);
Fig.drawLine(s-5,s+k*h/nums,s,s+k*h/nums);
Fig.drawString(Double.toString(Xmin+k*(Xmax-Xmin)/nums),
s+k*w/nums-5,s+h+15);
Fig.drawString(Double.toString(Ymin+k*(Ymах-Ymin)/nums),s-17,
s+h-1-k*h/nums);
}
Fig.setColor(gclr);
// grid lines:
for(k=1;k<=nums;k++){
Fig.drawLine(s+k*w/nums,s,s+k*w/nums,h+s);
Fig.drawLine(s,s+(k-1)*h/nums,s+w,s+(k-1)*h/nums);
}
// grаph display:
Fig.setColor(clr); // setting graph line color
// scaling coefficient:
double dx=(Xmax-Xmin)/w,dу=(Ymах-Ymin)/h;
// cartesian coordinates:
double x1,x2,y1,y2;
// window coordinates:
int h1,h2,w1,w2;
// initial values
x1=Xmin;
y1=0;
w1=s;
h1=h+s-(int)Math.round(y1/dу);
int step=5;
// displaying the dots and connecting them with lines:
for(int i=step;i<=w;i+=step){
x2=i*dx;
y2=y1+(x2-x1)*f(x2) ;
w2=s+(int)Math.round(x2/dx);
h2=h+s-(int)Math.round(y2/dу);
Fig.drawLine(w1,h1,w2,h2);
Fig.drawRect(w1-2,h1-2,4,4);
// new values:
x1=x2;
y1=y2;
w1=w2;
h1=h2;
}
}
}
// panel constructor
PPanel(){
// creating the object for the plot function:
G=new Plotter();
// setting the background color of the panel:
setBackground(Color.WHITE);
}
// redefinition of the paint method:
public void paint(Graphics g){
// when redrawing the panel redraw graph as well
G.plot(g);
}
}
this 是它在调色板上的外观。但是当我将它拖放到表单中时,什么也没有发生。默认元素工作得很好。怎么了?
【问题讨论】:
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当然,对不起,我的错。 cmets 现已翻译
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我通过使 Plotter 类独立并通过 ActionListener 在常规 JPanel 上使用它解决了这个问题(我按下按钮,Plotter 在 JPanel 上绘制)但我仍然需要覆盖 paint 方法不知何故,所以每次我调整窗口大小时 - 图表都会重绘。
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发现类似问题:stackoverflow.com/questions/14425476/… 我将字节码版本设置为 1.6,编译器也设置为 1.6,现在它可以正确添加(嗯,仍然无法正常工作,根本拒绝绘制任何东西,但它添加了至少)如果我在明天之前修复它,我将关闭问题
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最后一个问题 - 它不会调整大小。我设置了可以缩小,可以增长,想要增长,但它仍然非常小,除非我将首选大小强制为某些常数。当它是 -1,-1 - 它保持在小(我猜是零)大小
标签: java swing user-interface intellij-idea