我正在嘗試使單擊按鈕後執行某些任務的stoplight。這個指示燈應該做的是在50秒後從綠色變爲黃色,10秒後從黃色變爲紅色,60秒後從紅色變爲綠色(這部分我工作正常),並且如果按下按鈕時是綠色的,它應該變成黃色,這應該只有10秒後至少通過綠色。我有什麼問題是我該如何檢查10秒是否通過?Java線程處理
public class Stoplight extends Applet
{
Button cross;
public void init(){
cross = new Button("Cross");
add(cross);
StoplightCanvas stoplightCanvas = new StoplightCanvas(cross);
add(stoplightCanvas);
new StoplightThread(stoplightCanvas).start();
}
}
class StoplightCanvas extends Canvas implements ActionListener
{
int Xpos;
int Ypos;
int diameter;
Button cross;
int x = 1;
StoplightCanvas(Button cross)
{
this.cross = cross;
cross.addActionListener(this);
setSize(300, 600);
}
public void paint(Graphics g)
{
diameter = 70;
Xpos = 70;
Ypos = 50;
g.setColor(Color.BLUE);
g.fillRect(70, 50, 74, 220);
g.setColor(Color.WHITE);
if (x == 1)
g.setColor(Color.RED);
drawCircles(g, Xpos, Ypos);
g.setColor(Color.WHITE);
if (x == 2)
g.setColor(Color.YELLOW);
drawCircles(g, Xpos, Ypos + diameter);
g.setColor(Color.WHITE);
if (x == 3)
g.setColor(Color.GREEN);
drawCircles(g, Xpos, Ypos + diameter * 2);
}
public void actionPerformed(ActionEvent e)
{
if (e.getSource() == cross) {
}
repaint();
}
void drawCircles(Graphics g, int x, int y)
{
g.fillOval(x, y, diameter, diameter);
}
public void toggleColor() {
if (x == 1)
x = 3;
else if (x == 2)
x = 1;
else if (x == 3)
x = 2;
}
}
class StoplightThread extends Thread
{
StoplightCanvas stoplightCanvas;
StoplightThread(StoplightCanvas stoplightCanvas) {
this.stoplightCanvas = stoplightCanvas;
}
public void run()
{
while (true) {
try {
if (stoplightCanvas.x == 3){
Thread.sleep(50000);
} else if (stoplightCanvas.x == 2) {
Thread.sleep(10000);
} else if (stoplightCanvas.x == 1) {
Thread.sleep(60000);
}
} catch (InterruptedException e){}
stoplightCanvas.toggleColor();
stoplightCanvas.repaint();
}
}
}
1)爲什麼要編寫一個小程序?如果由於規格而到期。由老師,請參考[爲什麼CS老師應該停止教Java applets](http://programmers.blogoverflow.com/2013/05/why-cs-teachers-should-stop-teaching-java-applets/)。 2)爲什麼選擇AWT而不是Swing?在[Swing extras over AWT]上看到這個答案(http://stackoverflow.com/a/6255978/418556)有很多很好的理由放棄使用AWT組件。如果您需要支持較老的基於AWT的API,請參閱[混合重量級和輕量級組件](http://www.oracle.com/technetwork/articles/java/mixing-components-433992.html)。 – 2013-05-06 15:13:44