Adding Multiple ImageView

[M.Aamir khan]

just trying to add multiple images view to the Box but still no success... where i am going Wrong?

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.util.List;
import javafx.application.Application;
import javafx.beans.property.BooleanProperty;
import javafx.beans.property.SimpleBooleanProperty;
import javafx.event.ActionEvent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.input.DragEvent;
import javafx.scene.input.Dragboard;
import javafx.scene.input.TransferMode;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;


public class DragAndDropImages extends Application {

    ImageView[] imageView;
    Button clearBtn = new Button("Clear");
    Scene scene;
    VBox box;
    static int i = 0;

    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage window) {
        VBox root = BuildUI();
        scene = new Scene(root);
        scene.setOnDragOver(this::dragOver);
        scene.setOnDragDropped(this::dragDropped);

        window.setScene(scene);
        root.setStyle("-fx-padding: 10;"
                + "-fx-border-style: solid inside;"
                + "-fx-border-width: 2;"
                + "-fx-border-insets: 5;"
                + "-fx-border-radius: 5;"
                + "-fx-border-color: blue;");
        window.setTitle("Drag-and-Drop");
        window.show();
    }

    private VBox BuildUI() {
        Label msgLbl = new Label(
                "Drag and drop an image below.");
// Set the size for the image view
//        imageView.setFitWidth(50);
//        imageView.setFitHeight(50);
//        imageView.setSmooth(true);
//        imageView.setPreserveRatio(true);
//        

        clearBtn.setOnAction((ActionEvent e) -> {
            for (ImageView image : imageView) {
                image.setImage(null);
            }
        });
        //Set the Size for the Images View

        box = new VBox(10, msgLbl,clearBtn);
        return box;
    }

    private void dragOver(DragEvent de) {
        Dragboard db = de.getDragboard();
        if (db.hasFiles() || db.hasImage()) {
            de.acceptTransferModes(TransferMode.ANY);
        }
        de.consume();

    }

    private void dragDropped(DragEvent de) {
        boolean isDone = false;
        //transfer the Data
        Dragboard db = de.getDragboard();
        if (db.hasImage()) {
            this.transerImg(db.getImage());
            isDone = true;
        } else if (db.hasFiles()) {
            isDone = this.transferimgFromFile(db.getFiles());
        }
        //if data Transfer not Done
        de.setDropCompleted(isDone);
        de.consume();
    }

    private void transerImg(Image image) {
        
        imageView[i] = new ImageView();
        imageView[i].setCache(true);
        imageView[i].setImage(image);
        imageView[i].setFitHeight(50);
        imageView[i].setFitWidth(50);
        imageView[i].setPreserveRatio(true);
        imageView[i].setSmooth(true);
        box.getChildren().add(imageView[i]);
        System.out.println(imageView[i].getImage().getHeight());
        i++;
    }

    private boolean transferimgFromFile(List<File> files) {

        BooleanProperty isImage = new SimpleBooleanProperty();
        isImage.set(false);

        //Look for the First File MIME
        files.iterator().forEachRemaining(x -> {
            String mime;
            try {
                mime = Files.probeContentType(x.toPath());
                System.out.printf("File name = %s and File type = %s\n", x.getName(), mime);
                if (mime != null && mime.startsWith("image/")) {
                    this.transerImg(new Image(x.toURI().toURL().toExternalForm()));
                    isImage.set(true);
                }
            } catch (IOException e) {
                e.getMessage();
            }
        });

        return isImage.get();
    }

}

[Darryl Burke]

M.Aamir khan wrote:... still no success...

You need to TellTheDetails <- that's a link

Are any Exceptions thrown? I see a catch block with only e.getMessage() which returns a String that you don't do anything with. I would suggest replacing that with e.printStackTrace().

You do know that arrays need to be innitialized before they are used, don't you?

[M.Aamir khan]

oh my Bad ,,, i didn't init the array,,, thanks for the Hint...

but we can not predict the size of the input to init the array ..

[M.Aamir khan]

Are any Exceptions thrown?

No, There is no Exception thrown program is running fine but not adding any image to ImageView

and yes i initialize the array with

ImageView[] imageView = new ImageView[10];

but we know the size of input is unpredictable and once i initialize the array, lets say 10 in this case so it will fill with not more than 10 images and then here is the pro with this Code

clearBtn.setOnAction((ActionEvent e) -> {
            for (ImageView image : imageView) {
                image.setImage(null);
            }
        });

once you clear the ImageView it will not take data again because its still having some garbage i thought

[Darryl Burke]

M.Aamir khan wrote:but we can not predict the size of the input to init the array ..

Good use case for a List or other Collection. Have you dicovered the Oracle tutorials? Trail: Collections.

[M.Aamir khan]

Good use case for a List or other Collection.

Yup , Working Fine Now..

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.file.Files;
import java.util.LinkedList;
import java.util.List;
import javafx.application.Application;
import javafx.beans.property.BooleanProperty;
import javafx.beans.property.SimpleBooleanProperty;
import javafx.event.ActionEvent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.ScrollPane;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.input.DragEvent;
import javafx.scene.input.Dragboard;
import javafx.scene.input.TransferMode;
import javafx.scene.layout.TilePane;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;


public class DragAndDropImages extends Application {

    ImageView[] imageView;
    List<Image> AllImages = new LinkedList();
    Button clearBtn = new Button("Clear");
    Scene scene;
    TilePane imgBox;
    Label msgLbl = new Label(
            "Drag and drop images below.");

    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage window) {

        VBox root = BuildUI();
        scene = new Scene(root, 500, 500);
        scene.setOnDragDropped(this::dragDropped);
        scene.setOnDragOver(this::dragOver);

        window.setScene(scene);
        root.setStyle("-fx-padding: 10;"
                + "-fx-border-style: solid inside;"
                + "-fx-border-width: 2;"
                + "-fx-border-insets: 5;"
                + "-fx-border-radius: 5;"
                + "-fx-border-color: blue;");
        window.setTitle("Drag-and-Drop");
        window.show();
    }

    private VBox BuildUI() {
        imgBox = new TilePane();
        imgBox.setHgap(5.0);
        imgBox.setVgap(2.0);
        ScrollPane root = new ScrollPane(imgBox);
        root.setHbarPolicy(ScrollPane.ScrollBarPolicy.NEVER);
        root.setVbarPolicy(ScrollPane.ScrollBarPolicy.AS_NEEDED);
        root.setFitToWidth(true);

        clearBtn.setOnAction((ActionEvent e) -> {
            AllImages.clear();
            imgBox.getChildren().clear();
        });
        //Set the Size for the Images View

        VBox box = new VBox(10, msgLbl, root, clearBtn);
        return box;
    }

    private void dragOver(DragEvent de) {
        Dragboard db = de.getDragboard();
        if (db.hasFiles() || db.hasImage()) {
            de.acceptTransferModes(TransferMode.ANY);
        }
        de.consume();

    }

    private void dragDropped(DragEvent de) {
        
        boolean isDone = false;
        //transfer the Data
        Dragboard db = de.getDragboard();
        if (db.hasImage()) {
            addImg(db.getImage());
            updateView();
            isDone = true;
        } else if (db.hasFiles()) {
            isDone = transferimgFromFile(db.getFiles());
            updateView();

        }

        //if data Transfer not Done
        de.setDropCompleted(isDone);
        de.consume();

    }
    
    private void addImg(Image image) {
            AllImages.add(image);
            System.out.println("image added");
        }

        private boolean transferimgFromFile(List<File> files) {

            BooleanProperty isImage = new SimpleBooleanProperty();
            isImage.set(false);

            //Look for the First File MIME
            files.iterator().forEachRemaining(x -> {
                String mime;
                try {
                    mime = Files.probeContentType(x.toPath());
                    if (mime != null && mime.startsWith("image/")) {
                        this.addImg(new Image(new FileInputStream(x.getAbsoluteFile()), 50, 50, true, true));
                        isImage.set(true);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            });

            return isImage.get();
        }

        private void updateView() {
            System.out.println("updated");
            imageView = new ImageView[AllImages.size()];
            for (int j = 0; j < imageView.length; j++) {
                imageView[j] = new ImageView(AllImages.get(j));
                imageView[j].setFitHeight(50);
                imageView[j].setFitWidth(50);
                imageView[j].setSmooth(true);
                imageView[j].setPreserveRatio(true);
            }
            imgBox.getChildren().addAll(imageView);
            AllImages.clear();
        }


}

[hoji afzal]

Hi,

New to this forum!

The final solution worked for me, thank you! And I have this follow up question, if someone would like to tackle:

Looking at the code below, why do I need to initialize each ImageView array element twice? I initialized the whole array on line 16, which means I created 10 instances of ImageView. But if I don't initialize each one once again on line 20, I get a run time exception. Why do I need to do the exact same thing twice?

It seems I don't understand something fundamental about how Java initializes arrays of objects. Could someone explain this to me?

This is the error message:


Exception in Application start method
Exception in thread "main" java.lang.reflect.InvocationTargetException
       at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
       at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
       at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
       at java.lang.reflect.Method.invoke(Unknown Source)
       at sun.launcher.LauncherHelper$FXHelper.main(Unknown Source)
Caused by: java.lang.RuntimeException: Exception in Application start method
       at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
       at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$155(LauncherImpl.java:182)
       at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException
       at myJavaFx.start(myJavaFx.java:21)
       at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863)
       at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326)
       at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
       at java.security.AccessController.doPrivileged(Native Method)
       at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
       at com.sun.glass.ui.InvokeLaterDispatcher$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)
       ... 1 more

Thanks very much.

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.stage.Stage;
import javafx.scene.layout.FlowPane;
import javafx.scene.image.ImageView;
import javafx.scene.image.Image;

public class myJavaFx extends Application
{
    @Override
    public void start(Stage stage)
    {
        FlowPane pane = new FlowPane();

        Image image = new Image("2.jpg");
        ImageView[] imageView = new ImageView[10];

        for (int i = 0; i < 10; i++)
        {
            imageView[i] = new ImageView();
            imageView[i].setImage(image);
            imageView[i].setFitHeight(50);
            imageView[i].setFitWidth(50);
        }

        for (int i = 0; i < 10; i++)
        {
            pane.getChildren().add(imageView[i]);
        }

        Scene scene = new Scene(pane, 800, 100);

        stage.setScene(scene);
        stage.show();
    }
}

[Tim Cooke]

This line

ImageView[] imageView = new ImageView[10];

Creates as array of 10 empty ImageView sized buckets.

Then

imageView[i] = new ImageView();

puts a new instance of an ImageView in the bucket at index i.

Make sense?

[Campbell Ritchie]

Welcome to the Ranch

I suggest you consider an array initialiser intead of new Foo[123].
ImageView[] images = {new ImageView(), new ImageView(), ...};
That might be too longwinded for you to write here, but it will ensure you have no nulls in your array. You do however appear to be initiaising the array elements in the loop, so it is surprising that you are getting that Exception in your line 21. Try a line 20½:-
System.out.printf("ImageView != null %b%nImage != null %b%n", imageView[i], image);
That shou‍ld pick up any nulls. The %b tag can test a non‑Boolean object for nullity.
Don't use number literals in the for loop if at all possible. Not ...i < 10;... but ...i < myArray.length;...

[hoji afzal]

Hey,

Yes, it does make sense now!

I guess the clue is ImageView[10] versus ImageView().

Only ImageView() calls the constructor.

And I used a hard coded integer as a loop counter to make is easier for you to follow my code. Otherwise I avoid raw numbers there. Thanks for the suggestion.

Thank you very much!

Cheers

[hoji afzal]

And Campbell, I got the exception when I DIDN'T call the constructor. Once I used line 16 20 the code worked fine!

[Campbell Ritchie]

hoji afzal wrote:And Campbell, I got the exception when I DIDN'T call the constructor. Once I used line 1620 the code worked fine!

Aaaaaaaaaah! That makes it clear.
I shall edit the post for you.