[英]Can't execute button style methods (FXML button) from controller class. How can I setstyles of a FXML button and not using CSS for this?
我不能僅在if-then語句或方法中設置按鈕的樣式。
它可以很好地編譯,但是在運行應用程序時會出錯。 想法是在參數“ setnrColor”等於7時給按鈕着色。該按鈕分配有@FXML標簽。 當我不使用引用按鈕的setStyle / setTextFill方法時,邏輯工作良好。
運行時,出現以下錯誤:線程“ JavaFX Application Thread” java.lang.NullPointerException中的異常。 當調用“ setstyle方法時,會發生這種情況。
一個簡單的解釋說這是不可能的,這是有道理的。 到目前為止,我的所有搜索都沒有得到這個答案。 任何幫助表示贊賞。
public class FXMLDocumentController implements Initializable {
@FXML private Label label;
@FXML private Button btn;
@FXML private TextField text;
private int NrColor;
public void setButtonColor (int setnrColor){
boolean bln1;
NrColor = setnrColor;
if(NrColor==7){ //Expression is of type boolean
System.out.println("SAME NUMBER: SET COLOR BUTTON TO BLACK");
//btn.setStyle("-fx-base:black;"); //THIS LINE DOESNT WORK
bln1 = true;
//btn.getStyleClass().remove("armed");
}
else {
System.out.println("DIFFERENT NUMBER: SET COLOR BUTTON TO RED");
//btn.setStyle("-fx-base:red;"); //DOESNT WORK
bln1 = false;
trigger();
}
System.out.println("OUTPUT =" + bln1);
}
java.lang.NullPointerException:
at test_issue.FXMLDocumentController.trigger(FXMLDocumentController.java:64)
at test_issue.FXMLDocumentController.setButtonColor(FXMLDocumentController.java:53)
at test_issue.FlashingLight.lambda$start$1(FlashingLight.java:25)
at com.sun.scenario.animation.shared.TimelineClipCore.visitKeyFrame(TimelineClipCore.java:239)
at com.sun.scenario.animation.shared.TimelineClipCore.playTo(TimelineClipCore.java:180)
at javafx.animation.Timeline.impl_playTo(Timeline.java:176)
at javafx.animation.AnimationAccessorImpl.playTo(AnimationAccessorImpl.java:39)
at com.sun.scenario.animation.shared.FiniteClipEnvelope.timePulse(FiniteClipEnvelope.java:124)
at javafx.animation.Animation.impl_timePulse(Animation.java:1102)
at javafx.animation.Animation$1.lambda$timePulse$25(Animation.java:186)
at java.security.AccessController.doPrivileged(Native Method)
at javafx.animation.Animation$1.timePulse(Animation.java:185)
at com.sun.scenario.animation.AbstractMasterTimer.timePulseImpl(AbstractMasterTimer.java:344)
at com.sun.scenario.animation.AbstractMasterTimer$MainLoop.run(AbstractMasterTimer.java:267)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:506)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:490)
at com.sun.javafx.tk.quantum.QuantumToolkit.lambda$runToolkit$404(QuantumToolkit.java:319)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
at java.lang.Thread.run(Thread.java:745)
/////////////////////////////////////////////
<?xml version="1.0" encoding="UTF-8"?>
<?import java.lang.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<AnchorPane id="AnchorPane" prefHeight="200" prefWidth="320" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="test_issue.FXMLDocumentController">
<children>
<Label fx:id="label" layoutX="126" layoutY="120" minHeight="16" minWidth="69" />
<Button fx:id="btn" layoutX="104.0" layoutY="72.0" mnemonicParsing="false" prefHeight="56.0" prefWidth="136.0" text="Button" />
<TextField fx:id="text" layoutX="41.0" layoutY="14.0" promptText="HALLO" />
</children>
</AnchorPane>
您不應該創建控制器類的對象,需要從加載程序中提取以下內容:
FXMLLoader loader = new FXMLLoader(getClass().getResource("/main.fxml"));
AnchorPane root = loader.load();
FXMLDocumentController controller = loader.getController();
controller.setButtonColor(...);
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