我遇到一个问题,我有一个计时器类会改变我的 GUI 程序上的灯光。但我已经使用了 public void 方法行,所以我现在正在努力添加绘制图形 G。
/*public void paint(Graphics back)
{
back.setColor(Color.black);
back.fillRect(30,30,330,900); //make traffic light for car
back.fillRect(440,140,330,720); //make traffic light for peds
back.setColor(Color.red); //creates red circle
back.fillOval(45,45, 300, 280);
back.fillOval(455,155, 300, 280); //creates red ped circle
back.setColor(Color.yellow); //creates yellow circle
back.fillOval(45, 335, 300,280);
back.setColor(Color.green);
back.fillOval(45,625, 300, 280);
back.fillOval(455,555, 300, 280); //creates green ped circle
}*/
class LightChange implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
paint (Graphics back);
seconds++;
if (seconds == 0 & seconds <= 5)
{
back.setColor(Color.red); //creates red circle
back.fillOval(45,45, 300, 280);
}
else
{
back.setColor(Color.yellow); //creates yellow circle
back.fillOval(45, 335, 300,280);
}
repaint();
}
}
我收到错误消息,提示找不到后退符号。任何帮助都会很棒!
编辑:
我做了一些更改并尝试添加油漆(图形背面);进入类(class)。出现一些错误消息(非法的表达式开始)但是我的思路正确吗?
最佳答案
首先,您不应该有一个单独的类来实现 ActionListner
,因为这会使一切变得更加复杂。其次,就像 SLAks 所说的,你需要看看绘画是如何工作的。检查此链接 here .
现在,我会这样做:
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JPanel;
import javax.swing.Timer;
public class Draw extends JPanel implements ActionListener {
private Color topColorTraffic = Color.red;
private Color middleColorTraffic = Color.gray;
private Color bottomColorTraffic = Color.gray;
private Color topColorPeds = Color.gray;
private Color bottomColorPeds = Color.green;
// WE INITIALIZED THE UPPER VARIABLE LIKE THIS BECAUSE WE PRESUMED THAT
// IS RED FOR THE CARS AND GREEN FOR THE PEDS
private long startTime; // This will get the time when we've started the "animation"
private long targetTimeTraffic; // This will be the time we want the have
// between red changes to
// yellow in the traffic
private long targetTimeYellowLight; //This will be the time we want the yellow
//light to be displayed
private Timer t;
public Draw() {
startTime = System.currentTimeMillis();
targetTimeTraffic = 3000; // 3 sec
targetTimeYellowLight = 1200; //1.2 sec
t = new Timer(5, this); // this will call actionPerformed every 5 miliseconds
t.start();
}
public void paintComponent(Graphics back) {
super.paintComponent(back);
back.setColor(Color.black);
back.fillRect(30, 30, 330, 900); // make traffic light for car
back.fillRect(440, 140, 330, 720); // make traffic light for peds
back.setColor(topColorTraffic); // creates the top traffic circle
back.fillOval(45, 45, 300, 280);
back.setColor(topColorPeds); // creates the top peds circle
back.fillOval(455, 155, 300, 280);
back.setColor(middleColorTraffic); // creates the middle traffic circle
back.fillOval(45, 335, 300, 280);
back.setColor(bottomColorTraffic); // creates the bottom traffic circle
back.fillOval(45, 625, 300, 280);
back.setColor(bottomColorPeds); // creates the bottom peds circle
back.fillOval(455, 555, 300, 280);
}
public void actionPerformed(ActionEvent arg0) {
// changing from red to yellow in traffic
long currentTime = System.currentTimeMillis();
if (targetTimeTraffic <= currentTime - startTime) { //1st delay 3 sec
topColorTraffic = Color.gray;
middleColorTraffic = Color.yellow;
topColorPeds = Color.red;
bottomColorPeds = Color.gray;
}
//changing from yellow to green
if (targetTimeTraffic <= currentTime - startTime - targetTimeYellowLight) { //2nd delay 3 sec + another 1.2 sec
//but 3 sec were already for the 1st delay
// so we get only 1.2 sec delay
topColorTraffic = Color.gray;
middleColorTraffic = Color.yellow;
bottomColorTraffic = Color.green;
middleColorTraffic = Color.gray;
//startTime = System.currentTimeMillis();
}
//changing from green to yellow
if (targetTimeTraffic <= currentTime - startTime - targetTimeYellowLight - targetTimeTraffic) {
topColorTraffic = Color.gray;
bottomColorTraffic = Color.gray;
middleColorTraffic = Color.yellow;
}
//changing from yellow to red
if (targetTimeTraffic <= currentTime - startTime - 2* targetTimeYellowLight - targetTimeTraffic) {
topColorTraffic = Color.red;
middleColorTraffic = Color.gray;
topColorPeds = Color.gray;
bottomColorPeds = Color.green;
startTime = System.currentTimeMillis(); //reinitialize the variable
}
repaint();
}
}
如果您在理解代码时遇到问题,请随时询问。
关于java - 如何将油漆(图形g)添加到另一个类中?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/19641021/