我有我在这里创建的游戏的代码。编译很好，但是当我运行它时，我得到一个数字格式异常。我认为它与我的int express = Integer.parseInt（str）有关;但是我不确定。有人可以帮助我指出正确的方向吗？
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.image.Image;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Pane;
import javafx.stage.Stage;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedList;
import java.util.concurrent.atomic.AtomicReference;
public class Main extends Application {
@Override
public void start(Stage primaryStage) {
ArrayList<Integer> deck;
deck = new ArrayList<>();
int i = 1;
while(i < 52){
deck.add(i);
i++;
}
final AtomicReference<String> result = new AtomicReference<>("go.");
Collections.shuffle(deck);
BorderPane pane = new BorderPane();
HBox top = new HBox(10);
Label display = new Label(result.toString());
Button btShuffle = new Button("Shuffle");
btShuffle.setOnAction(
e -> {
Collections.shuffle(deck);
});
top.getChildren().add(display);
top.getChildren().add(btShuffle);
HBox center = new HBox(10);
Card card1 = new Card(deck.get(0));
center.getChildren().add(card1);
Card card2 = new Card(deck.get(1));
center.getChildren().add(card2);
Card card3 = new Card(deck.get(2));
center.getChildren().add(card3);
Card card4 = new Card(deck.get(3));
center.getChildren().add(card4);
HBox bottom = new HBox(10);
Label expression = new Label("Please Enter the expression: ");
bottom.getChildren().addAll(expression);
TextField tfExpress = new TextField();
LinkedList<Object> expInput = new LinkedList<>();
ArrayList<Character> signs = new ArrayList<>();
signs.add('/');
signs.add('+');
signs.add('(');
signs.add(')');
signs.add('-');
signs.add('^');
signs.add('*');
signs.add('%');
String str = tfExpress.getText();
char tempStor[] = str.toCharArray();
for(char c: tempStor)
{
expInput.add(c);
}
int express = Integer.parseInt(str);
expInput.removeIf(p-> p.equals(signs));
Button btVerify = new Button("Verify");
btVerify.setOnAction(
(ActionEvent e) -> {
if(card1.CardValue() == (int)expInput.get(0)
&& card2.CardValue() == (int)expInput.get(1)
&& card3.CardValue() == (int)expInput.get(2)
&& card4.CardValue() == (int)expInput.get(3)){
if(express == 24){
result.set("Correct");
}
else
result.set("Incorrect");
}
else
result.set("The numbers in the expression don't "
+ "match the numbers in the set.");
});
pane.setTop(top);
pane.setCenter(center);
pane.setBottom(bottom);
Scene scene = new Scene(pane);
primaryStage.setTitle("24 card game");
primaryStage.setScene(scene);
primaryStage.show();
}
public class Card extends Pane
{
public int cardVal;
Card(int card)
{
Image cardImage;
cardImage = new Image("card/"+ card +".png");
cardVal = card;
}
public int CardValue()
{
int card = 0;
if(cardVal <= 13)
{
card = cardVal;
}
else if(cardVal > 13 && cardVal <= 26)
{
card = cardVal - 13;
}
else if(cardVal > 26 && cardVal <= 39){
card = cardVal - 26;
}
else if(cardVal > 39 && cardVal <= 52){
card = cardVal - 39;
}
return card;
}
}
public static void main(String[] args) {
Application.launch(args);
}
}
以下是例外：
Exception in Application start method
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:367)
at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:305)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:767)
Caused by: java.lang.RuntimeException: Exception in Application start method
at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:894)
at com.sun.javafx.application.LauncherImpl.access$000(LauncherImpl.java:56)
at com.sun.javafx.application.LauncherImpl$1.run(LauncherImpl.java:158)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NumberFormatException: For input string: ""
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:592)
at java.lang.Integer.parseInt(Integer.java:615)
at Main.start(Main.java:81)
at com.sun.javafx.application.LauncherImpl$8.run(LauncherImpl.java:837)
at com.sun.javafx.application.PlatformImpl$7.run(PlatformImpl.java:335)
at com.sun.javafx.application.PlatformImpl$6$1.run(PlatformImpl.java:301)
at com.sun.javafx.application.PlatformImpl$6$1.run(PlatformImpl.java:298)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl$6.run(PlatformImpl.java:298)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$300(WinApplication.java:39)
答案 0 :(得分：1)
在获取文本并解析文本之前，只需几行就可以实例化TextField“tfExpress”。在尝试解析之前，您应该检查它是否为空或空。
答案 1 :(得分：0)
int express = Integer.parseInt(str);
在解析之前检查str是否为null。每当接收到数字的null /字符转换为Integer时，JVM将抛出NumberFormatException。使用Try，Catch块进行环绕以避免异常终止。