的JavaFX嘗試使用顏色拾取

Question

我試圖用這個

/** What happens when you click on the color picker button */ 
@FXML 
private void onColorPickerButton() { 
    Button[] buttons = {firstButton, secondButton, thirdButton}; 
    for(int i = 0; i < buttons.length; i++) { 
     buttons[i].setStyle(colorPicker.getStyle()); 
    } 
} 

改變我的按鈕的顏色改變按鈕colous但是，這只是給了我這樣的：

Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException 
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1762) 
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1645) 
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:198) 
at javafx.scene.Node.fireEvent(Node.java:8216) 
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:198) 
at javafx.scene.Scene$MouseHandler.process(Scene.java:3724) 
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3452) 
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1728) 
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2461) 
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:348) 
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:273) 
at java.security.AccessController.doPrivileged(Native Method) 
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:382) 
at com.sun.glass.ui.View.handleMouseEvent(View.java:553) 
at com.sun.glass.ui.View.notifyMouse(View.java:925) 
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method) 
at com.sun.glass.ui.win.WinApplication.lambda$null$141(WinApplication.java:102) 
at com.sun.glass.ui.win.WinApplication$$Lambda$37/1109371569.run(Unknown Source) 
at java.lang.Thread.run(Thread.java:745) 
Caused by: 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 sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71) 
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source) 
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
at java.lang.reflect.Method.invoke(Method.java:483) 
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275) 
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1759) 
... 47 more 
Caused by: java.lang.NullPointerException 
at com.gambling.client.GamblingClientController.onColorPickerButton(GamblingClientController.java:88) 
... 57 more 
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException 
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1762) 
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1645) 
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:198) 
at javafx.scene.Node.fireEvent(Node.java:8216) 
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:198) 
at javafx.scene.Scene$MouseHandler.process(Scene.java:3724) 
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3452) 
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1728) 
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2461) 
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:348) 
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:273) 
at java.security.AccessController.doPrivileged(Native Method) 
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:382) 
at com.sun.glass.ui.View.handleMouseEvent(View.java:553) 
at com.sun.glass.ui.View.notifyMouse(View.java:925) 
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method) 
at com.sun.glass.ui.win.WinApplication.lambda$null$141(WinApplication.java:102) 
at com.sun.glass.ui.win.WinApplication$$Lambda$37/1109371569.run(Unknown Source) 
at java.lang.Thread.run(Thread.java:745) 
Caused by: java.lang.reflect.InvocationTargetException 
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
at java.lang.reflect.Method.invoke(Method.java:483) 
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71) 
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source) 
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
at java.lang.reflect.Method.invoke(Method.java:483) 
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275) 
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1759) 
... 47 more 
Caused by: java.lang.NullPointerException 
    at    com.gambling.client.GamblingClientController.onColorPickerButton(GamblingClientController.java:88) 
... 57 more 

當我點擊按鈕。

，這是我的取色

/** The ColorPicker */ 
@FXML 
private ColorPicker colorPicker; 

我把FX：在現場製造商ID和已經做的一切，但我實在看不出有什麼不對

的按鈕：

/** The first button */ 
@FXML 
private Button firstButton; 

/** The second button */ 
@FXML 
private Button secondButton; 

與thirdButton相同的東西

Answer 1

異常的原因在控制器的88線NullPointerException：

Caused by: java.lang.NullPointerException at com.gambling.client.GamblingClientController. 
     onColorPickerButton(GamblingClientController.java:88) 

既然你不顯示所有的代碼，我只能猜測，在您的onColorPickerButton方法：

Button[] buttons = {firstButton, secondButton, thirdButton}; 
for(int i = 0; i < buttons.length; i++) { 
    buttons[i].setStyle(colorPicker.getStyle()); 
} 

按鈕不被初始化。如果他們沒有定義FXML文件（那麼他們沒有@FXML註釋），他們需要正確初始化。

編輯

鑑於該按鈕被初始化，以改變它們的顏色（我會承擔起自己的背景顏色）的一種方法是這樣的：

@FXML 
private void onColorPickerButton() { 
    Button[] buttons = {firstButton, secondButton, thirdButton}; 
    Color color = colorPicker.getValue(); 
    if(color!=null){ 
     for (Button button : buttons) { 
      button.setStyle("-fx-background-color: "+color.toString().replace("0x", "#")); 
     } 
    } 
}