[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?
我不能仅在if-then语句或方法中设置按钮的样式。
它可以很好地编译,但是在运行应用程序时会出错。 想法是在参数“ setnrColor”等于7时给按钮着色。该按钮分配有@FXML标签。 当我不使用引用按钮的setStyle / setTextFill方法时,逻辑工作良好。
运行时,出现以下错误:线程“ JavaFX Application Thread” java.lang.NullPointerException中的异常。 当调用“ setstyle方法时,会发生这种情况。
一个简单的解释说这是不可能的,这是有道理的。 到目前为止,我的所有搜索都没有得到这个答案。 任何帮助表示赞赏。
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>
您不应该创建控制器类的对象,需要从加载程序中提取以下内容:
FXMLLoader loader = new FXMLLoader(getClass().getResource("/main.fxml"));
AnchorPane root = loader.load();
FXMLDocumentController controller = loader.getController();
controller.setButtonColor(...);
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