[英]drawString() isn't drawing the String on my game
我正在使用drawString()
在字符串上写文本,但没有任何显示。 我将颜色设置为白色,并将坐标设置为(100,100)。 还有我在做错什么吗?
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.ArrayList;
import java.util.Random;
import javax.swing.JPanel;
public class Screen extends JPanel implements Runnable {
private static final long serialVersionUID = 1L;
public static final int WIDTH = 800, HEIGHT = 800;
private Thread thread;
private boolean running = false;
private BodyPart b;
private ArrayList<BodyPart> snake;
private Apple apple;
private ArrayList<Apple> apples;
private Random r;
private int xCoor = 20, yCoor = 20;
private int size = 10;
private int score = 0;
private boolean right = true, left = false, up = false, down = false;
private int ticks = 0;
private Key key;
public Screen() {
setFocusable(true);
key = new Key();
addKeyListener(key);
setPreferredSize(new Dimension(WIDTH, HEIGHT));
r = new Random();
snake = new ArrayList<BodyPart>();
apples = new ArrayList<Apple>();
start();
}
public void reset() {
snake.clear();
apples.clear();
xCoor = 20;
yCoor = 20;
size = 10;
score = 0;
running = true;
}
public void tick() {
if(snake.size() == 0) {
b = new BodyPart(xCoor, yCoor, 20);
snake.add(b);
}
if(apples.size() == 0) {
int xCoor = r.nextInt(40);
int yCoor = r.nextInt(40);
apple = new Apple(xCoor, yCoor, 20);
apples.add(apple);
}
for(int i = 0; i < apples.size(); i++) {
if(xCoor == apples.get(i).getxCoor() && yCoor == apples.get(i).getyCoor()) {
size++;
apples.remove(i);
score += 10;
i--;
}
}
for(int i = 0; i < snake.size(); i++) {
if(xCoor == snake.get(i).getxCoor() && yCoor == snake.get(i).getyCoor()) {
if(i != snake.size() - 1) {
reset();
}
}
}
if(xCoor < 0) xCoor = 40;
if(xCoor > 40) xCoor = 0;
if(yCoor < 0) yCoor = 40;
if(yCoor > 40) yCoor = 0;
ticks++;
if(ticks > 250000) {
if(right) xCoor++;
if(left) xCoor--;
if(up) yCoor--;
if(down) yCoor++;
ticks = 185000;
b = new BodyPart(xCoor, yCoor, 20);
snake.add(b);
if(snake.size() > size) {
snake.remove(0);
}
}
}
public void paint(Graphics g) {
g.clearRect(0, 0, WIDTH, HEIGHT);
g.drawString("Score: " + score, 100, 100);
g.setColor(Color.WHITE);
g.setColor(new Color(20, 50, 0));
g.fillRect(0, 0, WIDTH, HEIGHT);
g.setColor(Color.BLACK);
for(int i = 0; i < WIDTH / 20; i++) {
g.drawLine(i * 20, 0, i * 20, HEIGHT);
}
for(int i = 0; i < HEIGHT / 20; i++) {
g.drawLine(0, i * 20, WIDTH, i * 20);
}
for(int i = 0; i < snake.size(); i++) {
snake.get(i).draw(g);
}
for(int i = 0; i < apples.size(); i++) {
apples.get(i).draw(g);
}
}
public void start() {
running = true;
thread = new Thread(this, "Game Loop");
thread.start();
}
public void stop() {
running = false;
try {
thread.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public void run() {
while(running) {
tick();
repaint();
}
}
private class Key implements KeyListener {
public void keyPressed(KeyEvent e) {
int key = e.getKeyCode();
if(key == KeyEvent.VK_RIGHT && !left) {
up = false;
down = false;
right = true;
}
if(key == KeyEvent.VK_LEFT && !right) {
up = false;
down = false;
left = true;
}
if(key == KeyEvent.VK_UP && !down) {
left = false;
right = false;
up = true;
}
if(key == KeyEvent.VK_DOWN && !up) {
left = false;
right = false;
down = true;
}
}
}
请记住,您执行操作的顺序非常重要,请记住,在Swing中绘画就像在纸上绘画一样,如果先绘画文本然后在其上绘画,它将不再可见...
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(new Color(20, 50, 0));
g.fillRect(0, 0, WIDTH, HEIGHT);
g.setColor(Color.BLACK);
for (int i = 0; i < WIDTH / 20; i++) {
g.drawLine(i * 20, 0, i * 20, HEIGHT);
}
for (int i = 0; i < HEIGHT / 20; i++) {
g.drawLine(0, i * 20, WIDTH, i * 20);
}
for (int i = 0; i < snake.size(); i++) {
snake.get(i).draw(g);
}
for (int i = 0; i < apples.size(); i++) {
apples.get(i).draw(g);
}
g.setColor(Color.WHITE);
g.drawString("Score: " + score, 100, 100);
}
paintComponent
,您已经绕过了绘画过程,这意味着您可能会遇到各种讨厌的故障 super.paintComponent
看一下AWT中的绘画以及“摇摆和执行自定义绘画” ,以了解有关如何完成绘画的更多详细信息。
Swing也不是线程安全的,并且在更改绘制过程用来更新UI的任何内容时都需要小心,因为绘制可能会在任何时间以任何原因发生。
考虑使用Swing Timer
而不是Thread
。 计时器在事件调度线程的上下文中执行它的滴答事件,这使得从内部更新UI更加安全。 请参阅使用JFC / Swing创建GUI
您有几件事顺序错误。 绘画时,需要以正确的顺序绘画,否则将在其他对象的顶部绘画。
因此,在您的代码中, paint()
方法的前5行应如下所示(注意相同的代码,但顺序不同)
g.clearRect(0, 0, WIDTH, HEIGHT);
g.setColor(new Color(20, 50, 0));
g.fillRect(0, 0, WIDTH, HEIGHT);
g.setColor(Color.WHITE);
g.drawString("Score: " + score, 100, 100);
您需要先绘制背景色。 然后,您可以在其顶部绘制字符串。
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