java.lang.NullPointerException未知错误？？
程序代码：package application;
import java.util.LinkedList;
import java.util.Random;
import java.util.Timer;
import java.util.TimerTask;
import javafx.animation.KeyFrame;
import javafx.animation.KeyValue;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.beans.property.DoubleProperty;
import javafx.event.EventHandler;
import javafx.stage.Stage;
import javafx.util.Duration;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.input.KeyEvent;
import javafx.scene.paint.Color;
import javafx.scene.shape.Arc;
import javafx.scene.shape.ArcType;
import javafx.scene.shape.Circle;
public class Main extends Application
{
static String keyCode =null;
@Override
public void start(Stage stage)
{
Group g = new Group();
Scene scene = new Scene(g,1024,700);
LinkedList<Circle> list = new LinkedList<>();
LinkedList<Circle> list1 = new LinkedList<>();
//画食物
Random r = new Random();
for(int i=0;i<10;i++)
{
int x =r.nextInt(1009-15+1)+15;
int y =r.nextInt(685-15+1)+15;
Circle cir = new Circle();
cir.setCenterX(x);
cir.setCenterY(y);
cir.setRadius(15);
cir.setFill(Color.BLACK);
list1.add(cir);
}
//画蛇
Arc arc = new Arc();
arc.setFill(Color.BLACK);
arc.setCenterX(300);
arc.setCenterY(200);
arc.setRadiusX(15);
arc.setRadiusY(15);
arc.setStartAngle(45);
arc.setLength(270);
arc.setType(ArcType.ROUND);
for(int i=0;i<5;i++)
{
Circle cir = new Circle();
cir.setCenterX(270-30*i);
cir.setCenterY(200);
cir.setRadius(15);
cir.setFill(Color.BLACK);
list.add(cir);
}
//定义移动
class Move
{
public void moveObj(DoubleProperty arcValue, double arcMove)
{
Timeline timeline=new Timeline();
//head
KeyValue ARCValue = new KeyValue(arcValue,arcMove);
KeyFrame ARCkeyFrame = new KeyFrame(Duration.millis(500),ARCValue);
timeline.getKeyFrames().add(ARCkeyFrame);
//body
double preX=arc.getCenterX();
double preY=arc.getCenterY();
boolean isFirst=true;
for(int i=0;i<list.size();i++)
{
if(!isFirst)
{
preX=list.get(i-1).getCenterX();
preY=list.get(i-1).getCenterY();
}
KeyValue xValue= new KeyValue(list.get(i).centerXProperty(),preX);
KeyValue yValue= new KeyValue(list.get(i).centerYProperty(),preY);
KeyFrame keyFrame = new KeyFrame(Duration.millis(500),xValue,yValue);
timeline.getKeyFrames().add(keyFrame);
isFirst=false;
}
timeline.play();
}
}
//监听键盘事件
scene.setOnKeyReleased(new EventHandler<KeyEvent>()
{
public void handle(KeyEvent event)
{
keyCode=event.getText();
DoubleProperty arcValue=null;
double arcMove = 0;
switch(keyCode)
{
case "W":
case "w":
arcValue=arc.centerYProperty();
arcMove=arc.getCenterY()-30;
break;
case "A":
case "a":
arcValue=arc.centerXProperty();
arcMove=arc.getCenterX()-30;
break;
case "S":
case "s":
arcValue=arc.centerYProperty();
arcMove=arc.getCenterY()+30;
break;
case "D":
case "d":
arcValue=arc.centerXProperty();
arcMove=arc.getCenterX()+30;
break;
}
Move move = new Move();
move.moveObj(arcValue,arcMove);
Timer timer = new Timer();
timer.schedule(new TimerTask()
{
public void run()
{
DoubleProperty arcValue=null;
double arcMove = 0;
switch(keyCode)
{
case "W":
case "w":
arcValue=arc.centerYProperty();
arcMove=arc.getCenterY()-30;
break;
case "A":
case "a":
arcValue=arc.centerXProperty();
arcMove=arc.getCenterX()-30;
break;
case "S":
case "s":
arcValue=arc.centerYProperty();
arcMove=arc.getCenterY()+30;
break;
case "D":
case "d":
arcValue=arc.centerXProperty();
arcMove=arc.getCenterX()+30;
break;
}
if(event.getText()!=null)
{
move.moveObj(arcValue,arcMove);
}
}
}
,10,100);
//吃食物
Timer timer1 = new Timer();
timer1.schedule(new TimerTask()
{
double arcX=arc.getCenterX();
double arcY=arc.getCenterY();
public void run()
{
for(int i=0;i<list1.size();i++)
{
double cirX=list1.get(i).getCenterX();
double cirY=list1.get(i).getCenterX();
double distance=Math.sqrt((arcX-cirX)*(arcX-cirX)+(arcY-cirY)*(arcY-cirY));
if(distance<30)
{
list.add(list1.get(i));
list1.remove(i);
}
}
}
}
,10,100);
}//hanndle
}//listen
);
g.getChildren().addAll(list);
g.getChildren().addAll(list1);
g.getChildren().add(arc);
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch(args);
}
}
蛇不能吃食物？？？
求大神解！！！！
月月姐在吗？？@林月儿
