[英]Numbers not showing up on JFrame
這是顯示數字的線程:
class CoOrdCounter extends Thread{
public void run(){
try{
while(true){
Thread.sleep(500);
printX = cow.x;
printY = cow.y;
}
}catch(Exception e){}
}
}
//Of course I also have CoOrdCounter co = new CoOrdCounter; co.start();
接着...
g.drawString("Co-ords: ("+printX+","+printY+")",50,100);
它總是顯示(0,0)
,可能是因為int printX = 0, printY = 0;
。 所以這意味着變量根本沒有改變...為什么? 我該如何做...?
[請]我知道我不應該使用paint(),但是我是初學者,所以...
[編輯]既然MadProgrammer提到了它,我確實收到了EventDispatchThread錯誤。
[編輯2]我了解使用Timer
但是@MadProgrammer
如何使用您的代碼段獲取cow.x
和cow.y
?
[編輯3]如果您鍵入鍵p
, KeyListener
將啟動Thread
Slider
的實例thread
。
[UPDATE CLASS 2(真品)]
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;
import java.io.*;
import java.net.*;
@SuppressWarnings({"serial","rawtypes","unchecked"})
public class CowbenderI extends JFrame implements MouseListener, KeyListener{
CoOrdCounter co;
Counter cnt;
Icon icon = new ImageIcon("resources/img/cow.png");
int focusX = 0, focusY = 0, counter = 0;
ArrayList lines = new ArrayList();
Point2D.Double start;
final Color BROWN = new Color(156,93,82);
Slider thread;
Rectangle cow = null;
boolean drawGuy = false, useFinal = false, checkedForWin = false, alive = true;
int finalTime = 0;
int printX = 0, printY = 0;
public CowbenderI(){
super("Cowbender I - \"Slope Run\"");
setSize(700,700);
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
addMouseListener(this);
addKeyListener(this);
cnt = new Counter();
cnt.go = false;
cnt.start();
co = new CoOrdCounter();
co.go = false;
co.start();
}
public void paint(Graphics g){
super.paint(g);
try{
g.setColor(Color.WHITE);
g.fillRect(-2000, -2000, 5000, 5000);
URL url = this.getClass().getResource("resources/img/world/slope.png");
Image bckgrnd = Toolkit.getDefaultToolkit().getImage(url);
g.drawImage(bckgrnd,0,0,this);
}catch(Exception e){}
g.setColor(BROWN);
for(int i = 0; i < lines.size(); i++){
Line2D.Double temp = (Line2D.Double) lines.get(i);
int x1 = Integer.parseInt(""+Math.round(temp.getX1()));
int x2 = Integer.parseInt(""+Math.round(temp.getX2()));
int y1 = Integer.parseInt(""+Math.round(temp.getY1()));
int y2 = Integer.parseInt(""+Math.round(temp.getY2()));
g.drawLine(x1-focusX,y1-focusY,x2-focusX,y2-focusY);
}
if(drawGuy){
try{
g.setFont(new Font("Arial",Font.BOLD,16));
if(useFinal == false) g.drawString("Current Time: "+counter,50,50);
else g.drawString("Current Time: "+finalTime,50,50);
g.drawString("Co-ords: ("+printX+","+printY+")",50,100);
if(alive == true){
URL url = this.getClass().getResource("resources/img/world/char.png");
Image image = Toolkit.getDefaultToolkit().getImage(url);
g.drawImage(image, cow.x-focusX, cow.y-focusY, this);
}
else{
URL url = this.getClass().getResource("resources/img/world/deadchar.png");
Image image = Toolkit.getDefaultToolkit().getImage(url);
g.drawImage(image, cow.x-focusX, cow.y-focusY, this);
if(checkedForWin == false){
finalTime = counter;
useFinal = true;
checkWin();
}
}
} catch(Exception exc){}
focusX = cow.x-100;
focusY = cow.y-100;
}
}
public void checkWin(){
if(finalTime >= 45){
JOptionPane.showMessageDialog(null,"You won!\nThe farmer got tired and ran back!","Cowbender I - The Slope",JOptionPane.INFORMATION_MESSAGE,icon);
System.exit(0);
}
}
public void mouseClicked(MouseEvent e){}
public void mouseEntered(MouseEvent e){}
public void mouseExited(MouseEvent e){}
public void mousePressed(MouseEvent e){
start = new Point2D.Double(e.getX()+focusX,e.getY()+focusY);
}
public void mouseReleased(MouseEvent e){
Point2D.Double end = new Point2D.Double(e.getX()+focusX,e.getY()+focusY);
lines.add(new Line2D.Double(start,end));
repaint();
}
public void keyPressed(KeyEvent e){}
public void keyReleased(KeyEvent e){}
public void keyTyped(KeyEvent e){
if(e.getKeyChar()=='w'||e.getKeyChar()=='W'){
focusY-=100;
repaint();
}
if(e.getKeyChar()=='a'||e.getKeyChar()=='A'){
focusX-=100;
repaint();
}
if(e.getKeyChar()=='s'||e.getKeyChar()=='S'){
focusY+=100;
repaint();
}
if(e.getKeyChar()=='d'||e.getKeyChar()=='D'){
focusX+=100;
repaint();
}
if(e.getKeyChar()=='p'||e.getKeyChar()=='P'){
alive = true;
counter = 0;
cnt.go = true;
co.go = true;
useFinal = false;
thread = new Slider();
thread.start();
thread.action(true);
}
if(e.getKeyChar()=='z'||e.getKeyChar()=='Z'){
lines.remove(lines.size()-1);
repaint();
}
if(e.getKeyChar()=='x'||e.getKeyChar()=='X'){
int response = milkSwing.confirmBox(null, "Do you really want to remove all of your summoned earth?", "Cowbender - The Slope", JOptionPane.YES_NO_OPTION);
if(response == JOptionPane.YES_OPTION) lines.clear();
repaint();
}
if(e.getKeyChar()=='q'||e.getKeyChar()=='Q'){
System.exit(0);
}
}
class CoOrdCounter extends Thread{
public boolean go = true;
public void run(){
try{
while(true){
if(go){
Thread.sleep(500);
printX = cow.x;
printY = cow.y;
repaint();
}
}
}catch(Exception e){}
}
}
class Counter extends Thread{
public boolean go = true;
public void run(){
try{
while(true){
if(go){
Thread.sleep(1000);
counter++;
}
}
} catch(Exception e){}
}
}
private class Slider extends Thread{
double velocity, gravity;
boolean go = false;
public void run(){
if(go){
initGuy();
velocity = 0;
gravity = 1;
}
while(go){
try{
Line2D.Double lineTaken = null;
boolean onLine = false;
int firstOnLine = -1;
for(int i = lines.size()-1; i>=0; i--){
Line2D.Double temp = (Line2D.Double) lines.get(i);
if(temp.intersects(cow.x,cow.y,50,50)){
lineTaken = temp;
onLine = true;
if(firstOnLine!=i){
firstOnLine = i;
gravity = 0;
}
break;
}
}
if(onLine){
double grav = (lineTaken.y2-lineTaken.y1)/50;
double vlct = (lineTaken.x2-lineTaken.x1)/100;
if(velocity<5)velocity+=vlct;
if(gravity<2.5)gravity+=grav;
}
else{
gravity+=.2;
}
cow.x+=velocity;
cow.y+=gravity;
if(cow.x > 10000) alive = false;
Thread.sleep(75);
repaint();
}catch(Exception e){break;}
}
}
public void action(boolean b){
go = b;
}
public void initGuy(){
Line2D.Double firstLine = (Line2D.Double) lines.get(0);
int x = Integer.parseInt(""+Math.round(firstLine.x1));
int y = Integer.parseInt(""+Math.round(firstLine.y1));
cow = new Rectangle(x+90,y-60,50,50);
drawGuy = true;
}
}
/**
* @param args
*/
public static void main(String[] args) {
CowbenderI g = new CowbenderI();
}
}<br />
[EDIT 4] @MadProgrammer不起作用:
您需要告訴Swing您想要更新UI。 在這種情況下,由於可能違反與事件調度線程的約定,因此會出現問題(除了事件調度線程之外,您永遠都不應從其他任何線程更新UI)
我在下面完成的示例使用了一個簡單的javax.swing.Timer
,它克服了這個問題。
public class PrintNumbers {
public static void main(String[] args) {
new PrintNumbers();
}
public PrintNumbers() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new PrintPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class PrintPane extends JPanel {
private int printX;
private int printY;
public PrintPane() {
Timer timer = new Timer(500, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
printX = (int) Math.round(Math.random() * 1000);
printY = (int) Math.round(Math.random() * 1000);
repaint();
}
});
timer.setRepeats(true);
timer.setCoalesce(true);
timer.start();
}
@Override
public Dimension getPreferredSize() {
return new Dimension(100, 100);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
int width = getWidth() - 1;
int height = getHeight() - 1;
FontMetrics fm = g.getFontMetrics();
String text = printX + "x" + printY;
int x = (width - fm.stringWidth(text)) / 2;
int y = ((height - fm.getHeight()) / 2) + fm.getAscent();
g.drawString(text, x, y);
}
}
}
更新
從示例代碼。
首先,列出您的示例代碼有問題的地方...
JFrame
擴展或覆蓋paint
方法。 您最好從JPanel
擴展並覆蓋paintComponent
。 首先,這將為您提供自動雙緩沖,其次,它將為您提供靈活的部署選項(將面板添加到JFrame
或JApplet
) go
為假)的線程正在浪費CPU,因為這些線程仍需要安排運行時間。 通讀並發 ,特別是同步和鎖 KeyListener
使用鍵綁定 API。 它具有更好的焦點控制(組件不必具有焦點即可觸發操作),並且可以生成可插拔和可重用的代碼。 catch (Exception e) {}
不會告訴您任何錯誤。 至少您應該記錄該異常。 至於你的問題..
首先使CoOrdCounter#go
, Counter#go
, Slider#go
和Cow
Slider#go
易失 。
我擺脫了CoOrdCounter#go
,能夠正確看到打印到控制台的結果(由於上述原因,圖形在我的計算機上不起作用)
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.