Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
at game.updateLocation(game.java:52)
at worldMap.startGame(worldMap.java:72)
at gameRun.lambda$start$0(gameRun.java:63)
at gameRun$$Lambda$1/424873723.handle(Unknown Source)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.event.Event.fireEvent(Event.java:204)
at javafx.scene.Node.fireEvent(Node.java:8175)
at javafx.scene.control.Button.fire(Button.java:185)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:182)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:96)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:89)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:204)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3746)
at javafx.scene.Scene$MouseHandler.access$1800(Scene.java:3471)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1695)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2486)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:314)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:243)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:345)
at com.sun.glass.ui.View.handleMouseEvent(View.java:526)
at com.sun.glass.ui.View.notifyMouse(View.java:898)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$300(WinApplication.java:39)
at com.sun.glass.ui.win.WinApplication$4$1.run(WinApplication.java:112)
at java.lang.Thread.run(Thread.java:745)
以下代码的触发器来自gameRun.java：
worldMap map = new worldMap();
map.startGame(game);
我尝试单击播放按钮时出现的错误。 worldMap.java中的代码片段如下
Location YourHometown, Beach;
Location newLocation;
public void createLocations()
{
YourHometown = new Location("Your Hometown", "Everyone smiles here and talks about sunshines and rainbows. It has a familiar scent of roasted pigs and handknit socks.", "YourHometown.mp3", "Town");
newLocation = YourHometown;
Beach = new Location("Beach", "It's Beachy", "Beach.mp3", "Zone");
}
public void startGame(game Game)
{
createLocations();
Game.updateLocation(newLocation);
}
而Game.updateLocation()是指game.java
public void updateLocation (Location newLocation){
...
}
Location是它自己独立的类，是一个Object。理想情况下，每次按下具有与当前位置不同的位置的按钮时，此代码应该做的是更改newLocation。显示的代码的目标是将默认Location设置为YourHometown Location对象。
但是，一旦我们运行Game.updateLocation(newLocation);并且出现以下错误，代码就会中断，虽然我知道NullPointerException是什么，但我不知道如何在给定的JavaFX上下文中修复它。
我的理由是为了运行代码，使用createLocations();方法将代码强制转换为startGame()，因此不应该成为newLocation的原因为空（因为newLocations设置为YourHometown）。为了测试我的逻辑，我在startGame()下运行了以下代码，它仍然返回了相同的错误：
public void startGame(game Game)
{
createLocations();
if(newLocation != null)
{
Game.updateLocation(newLocation);
}
else
{
System.out.println("Break");
}
}
控制台没有打印＆＃34; Break＆＃34; line，表示newLocation确实不为null，但运行updateLocation()的脚本并返回错误
TL; DR结论
public void updateLocation (Location newLocation){
if(bgm.getStatus().equals(Status.PLAYING))
{
timeline = new Timeline(new KeyFrame(Duration.seconds(2), new KeyValue(bgm.volumeProperty(), 0)));
timeline.play();
bgm.stop();
}
bg = new Media(new File(newLocation.getMusic()).toURI().toString());
bgm = new MediaPlayer(bg);
bgm.play();
timeline = new Timeline(new KeyFrame(Duration.seconds(2), new KeyValue(bgm.volumeProperty(), 1)));
timeline.play();
}
除了上面给出的方法之外，一切都应该有效。我认为这可能是某种文件/媒体播放器问题，但我不知道如何解决它。 updateLocation()的功能应该是从前一个位置的音乐到下一个位置的平滑过渡（之前的音乐淡出 - > nextLocation音乐淡入）。它调用位于脚本所在文件夹中的.mp3文件。
任何帮助表示赞赏，如果缺少任何额外信息，我可以提供。我试着简化它以减少阅读。
答案 0 :(得分：0)
致电时
map.startGame(game);
游戏为空。我无法看到您是否从粘贴的代码中为其指定了任何值。