我有一个名为“AdjustmentBar”的类，其中包括一个 imageView、一个菜单栏和一些图片编辑功能(一个 FXML 文件和一个 Controller )。 AdjustmentBar 被加载到另一个名为“ExaminationDisplayer”的类(也是一个 FXML 文件和一个 Controller )。 ExaminationDisplayer 从在线 MySQL 数据库加载一些图像，我希望每个图像都显示在单独的 imageView 中。
我已经能够将AdjustmentBar加载到ExaminationDisplayer中，但我不知道如何setImage()包含在AdjustmentBar中的imageView。我可以在我专门在 ExaminationDisplayer 中制作的 ImageView 中显示数据库中的图像，并且如果我单独运行该 View ，则可以在调整栏 View 中显示图片。我只是无法让加载的调整栏在 ExaminationDisplayer 中显示图像。
当我运行它时，这行代码出现 nullpointerException 错误:imgView.setImage(image)，位于 ExaminationDisplayerController 中:
public class ExaminationDisplayerController extends AdjustmentBarController {
@FXML
private void handlebtnFraminghamAction(ActionEvent event) throws IOException {showCardiacConditionEstimator(); }
@FXML
private AnchorPane anchorPane;
@FXML
private LineChart<Number, Number> lcChart;
@FXML
private NumberAxis xAxis; // x-Axis is defined
@FXML
private NumberAxis yAxis; //y-Axis is defined
public void initialize() throws ClassNotFoundException, SQLException, IOException { // Loading methods in ExaminationDisplayerController
SPECTLoad();
}
public void showCardiacConditionEstimator() throws IOException { // Method for displaying CardiacConditionEstimator
Parent parent = FXMLLoader.load(getClass().getResource("/fxml/CardiacConditionEstimator.fxml")); //Reference to the fxml file
Stage stage = new Stage(); // creating a new stage
Scene scene = new Scene(parent); // creating a new scene for the file to be shown onto
stage.setScene(scene); // sets the scene on the stage
stage.show(); // Displaying the stage
stage.setMaximized(false); // maximizing the stage
}
public void SPECTLoad() throws SQLException, ClassNotFoundException {
DBConnection dbConn = new DBConnection();
Connection conn = dbConn.connect();
PreparedStatement pstmt = null;
try {
for (int numberOfExaminations = 0; numberOfExaminations < 3; numberOfExaminations++) {
String[] ID = {"1111", "1112", "1113"};
List<String> chosenExaminations = Arrays.asList(ID);
String SQL = "SELECT `IMAGE` FROM `SPECT` WHERE `ID` = ?;";
pstmt = conn.prepareStatement(SQL);
pstmt.setString(1, chosenExaminations.get(numberOfExaminations));
ResultSet rs = pstmt.executeQuery();
while (rs.next()) {
InputStream is = rs.getBinaryStream("IMAGE");
OutputStream os = new FileOutputStream(new File("SPECT_IMAGE.jpg"));
byte[] content = new byte[1024];
int size = 0;
while ((size = is.read(content)) != -1) { // Når inputstream er real passer den et -1 værdi og så stoppes loopet
os.write(content, 0, size);
}
os.close();
is.close();
Image image = new Image(new File("SPECT_IMAGE.jpg").toURI().toString(), 200, 200, true, true);
anchorPane.getChildren().add(FXMLLoader.load(getClass().getResource("/fxml/AdjustmentBar.fxml")));
imgView.setImage(image);
}
}
//}
} catch (Exception e) {
e.printStackTrace();
}
}
这是AdjustmentBarController的代码:
public class AdjustmentBarController {
@FXML
private AnchorPane AnchorPane;
@FXML
private ScrollPane ScrollPane;
@FXML
public ImageView imgView;
@FXML
private Slider contrastAdjuster;
@FXML
private ToggleButton btnMeasure;
@FXML
private Pane imgContainer;
@FXML
private Label txtLabel;
@FXML
private void btnZoomInAction(ActionEvent event) {...}
@FXML
private void btnZoomOutAction(ActionEvent event) {...}
@FXML
private void btnRotateRightAction(ActionEvent event) {...}
@FXML
private void btnRotateLeftAction(ActionEvent event) {...}
/**
* Initializes the controller class.
*
* @param url
* @param rb
*/
public void initialize(URL url, ResourceBundle rb
) {
contrastAdjuster.valueProperty().addListener((observable, oldValue, newValue) -> {
double value = contrastAdjuster.getValue();
ColorAdjust colorAdjust = new ColorAdjust();
colorAdjust.setContrast(value);
imgView.setEffect(colorAdjust);
});
}
}
我不确定调整栏的 FXML 文件是否相关，但这里是:
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.geometry.Insets?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.ScrollPane?>
<?import javafx.scene.control.Slider?>
<?import javafx.scene.control.ToggleButton?>
<?import javafx.scene.image.Image?>
<?import javafx.scene.image.ImageView?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.BorderPane?>
<?import javafx.scene.layout.HBox?>
<?import javafx.scene.layout.Pane?>
<AnchorPane id="AnchorPane" prefHeight="435.0" prefWidth="435.0" xmlns="http://javafx.com/javafx/8.0.111" xmlns:fx="http://javafx.com/fxml/1" fx:controller="Multimodality.controller.AdjustmentBarController">
<children>
<BorderPane prefHeight="435.0" prefWidth="435.0" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
<center>
<ScrollPane fx:id="ScrollPane" pannable="true" prefHeight="435.0" prefWidth="435.0" BorderPane.alignment="CENTER">
<content>
<Pane fx:id="imgContainer">
<children>
<ImageView fx:id="imgView" fitHeight="400.0" fitWidth="400.0" nodeOrientation="INHERIT" pickOnBounds="true" preserveRatio="true" />
<Label fx:id="txtLabel" alignment="TOP_LEFT" layoutX="336.0" layoutY="-1.0" prefHeight="134.0" prefWidth="75.0" wrapText="true" />
</children>
</Pane>
</content>
</ScrollPane>
</center>
<bottom>
<HBox alignment="CENTER" prefHeight="35.0" prefWidth="435.0" spacing="8.0" BorderPane.alignment="CENTER">
<children>
<Button fx:id="btnZoomOut" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" mnemonicParsing="false" onAction="#btnZoomOutAction" prefHeight="25.0" prefWidth="25.0">
<graphic>
<ImageView fitHeight="20.0" fitWidth="20.0" preserveRatio="true">
<image>
<Image url="/img/icon_zoomout.png" />
</image>
</ImageView>
</graphic>
</Button>
<Button fx:id="btnZoom100" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" mnemonicParsing="false" onAction="#btnZoom100Action" prefHeight="25.0" prefWidth="25.0">
<graphic>
<ImageView fitHeight="20.0" fitWidth="20.0" preserveRatio="true">
<image>
<Image url="/img/icon_fit.png" />
</image>
</ImageView>
</graphic>
</Button>
<Button fx:id="btnZoomIn" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" mnemonicParsing="false" onAction="#btnZoomInAction" prefHeight="25.0" prefWidth="25.0">
<graphic>
<ImageView fitHeight="20.0" fitWidth="20.0" preserveRatio="true">
<image>
<Image url="/img/icon_zoomin.png" />
</image>
</ImageView>
</graphic>
</Button>
<Button fx:id="btnRotateRight" contentDisplay="CENTER" graphicTextGap="0.0" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" mnemonicParsing="false" onAction="#btnRotateRightAction" prefHeight="25.0" prefWidth="25.0">
<graphic>
<ImageView fitHeight="20.0" fitWidth="20.0" preserveRatio="true">
<image>
<Image url="/img/shape_rotate_clockwise.png" />
</image>
</ImageView>
</graphic>
</Button>
<Button fx:id="btnRotateLeft" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" mnemonicParsing="false" onAction="#btnRotateLeftAction" prefHeight="25.0" prefWidth="25.0">
<graphic>
<ImageView fitHeight="20.0" fitWidth="20.0" preserveRatio="true">
<image>
<Image url="/img/shape_rotate_anticlockwise.png" />
</image>
</ImageView>
</graphic>
</Button>
<ToggleButton fx:id="btnMeasure" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" mnemonicParsing="false" onAction="#btnMeasureAction" prefHeight="25.0" prefWidth="25.0">
<graphic>
<ImageView fitHeight="20.0" fitWidth="20.0" preserveRatio="true">
<image>
<Image url="/img/ruler.png" />
</image>
</ImageView>
</graphic>
</ToggleButton>
<ImageView fitHeight="20.0" fitWidth="20.0" preserveRatio="true">
<image>
<Image url="/img/contrast.png" />
</image>
<HBox.margin>
<Insets left="8.0" right="-2.0" />
</HBox.margin>
</ImageView>
<Slider fx:id="contrastAdjuster" blockIncrement="0.1" majorTickUnit="0.5" max="1.0" min="-1.0" minorTickCount="4" prefHeight="24.0" prefWidth="128.0" showTickMarks="true" />
</children>
<BorderPane.margin>
<Insets />
</BorderPane.margin>
</HBox>
</bottom>
</BorderPane>
</children>
</AnchorPane>
最后但同样重要的是，这是运行代码时得到的 nullPointerException:
java.lang.NullPointerException
at Multimodality.controller.ExaminationDisplayerController.SPECTLoad(ExaminationDisplayerController.java:224)
at Multimodality.controller.ExaminationDisplayerController.initialize(ExaminationDisplayerController.java:86)
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:498)
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:498)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2566)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3214)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
at Multimodality.controller.ExaminationOverviewController.showExaminationDisplayer(ExaminationOverviewController.java:352)
at Multimodality.controller.ExaminationOverviewController.btnChooseExaminationsAction(ExaminationOverviewController.java:341)
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:498)
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:498)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1769)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1657)
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.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:8413)
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.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$MouseHandler.process(Scene.java:3757)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:381)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:417)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:416)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
at java.lang.Thread.run(Thread.java:745)
BUILD SUCCESSFUL
Total time: 52.909 secs
希望大家能够帮助我!预先感谢您:-)
最佳答案
每当您有需求并且需要将控件公开时，这就是代码味道。切勿暴露您的 UI 节点。
最好的方法是在 AdjustmentBarController 中添加一个方法来接受图像。然后，此方法将在 Controller 中定义的 ImageView 中设置此图像。
public class AdjustmentBarController {
...
@FXML
private ImageView imgView;
...
public void setImage(Image image) {
imgView.setImage(image);
}
}
现在，一旦完成了。不要从 AdjustmentBarController 扩展 ExaminationDisplayerController。
对于在 ExaminationDisplayerController 中加载的每个图像，加载 AdjustmentBar 的 FXML 文件，从 FXMLLoader 获取 Controller 并在 Controller 中设置图像。
// Do not extend from AdjustmentBarController
public class ExaminationDisplayerController {
...
public void SPECTLoad() throws SQLException, ClassNotFoundException {
DBConnection dbConn = new DBConnection();
...
Image image = new Image(new File("SPECT_IMAGE.jpg").toURI().toString(), 200, 200, true, true);
FXMLLoader loader = new FXMLLoader(getClass().getResource("/fxml/AdjustmentBar.fxml"));
AnchorPane anchorPaneFromAdjustmentBar = loader.load();
anchorPane.getChildren().add(anchorPaneFromAdjustmentBar);
// Get the controller from the FXMLLoader
AdjustmentBarController controller = (AdjustmentBarController) loader.getController();
// Set the image
controller.setImage(image);
...
}
}
欲了解更多信息，请访问:
关于Javafx setImage for ImageView 来自另一个 FXML Controller ，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/43916083/