Implementation of manual move-function via the java-server-api

imageviewer-addon/src/main/java/org/tepi/imageviewer/ImageViewer.java

@@ -6,6 +6,7 @@
 import java.util.LinkedList;
 import java.util.List;
 
+import org.tepi.imageviewer.client.Directions;
 import org.tepi.imageviewer.client.ImageViewerServerRpc;
 import org.tepi.imageviewer.client.ImageViewerState;
 
@@ -62,8 +63,17 @@ public void centerImageSelected(int newCenterImageIndex) {
 				}
 			}
 		}
+		/**
+		 * rpc call to reset the move direction
+		 */
+		@Override
+		public void moveFinished() {
+			ImageViewer.this.getState().direction = Directions.NODIRECTION;
+		}
 	};
 
+
+
 	/**
 	 * Default constructor of ImageViewer.
 	 * 
@@ -90,6 +100,15 @@ protected ImageViewerState getState() {
 		return (ImageViewerState) super.getState();
 	}
 
+	/**
+	 * Trigger a movement of the current image to the left/right. Will trigger the animation, if the animation is enabled.
+	 * 
+	 * @param direction The direction the images will scroll.
+	 */
+	public void move(Directions direction) {
+		this.getState().direction = direction;
+	}
+
 	/**
 	 * Returns (an unmodifiable) copy of the list of images currently set to
 	 * this ImageViewer.

imageviewer-addon/src/main/java/org/tepi/imageviewer/client/Directions.java

@@ -0,0 +1,9 @@
+package org.tepi.imageviewer.client;
+
+/**
+ * possible move directions
+ */
+public enum Directions {
+
+	LEFT, RIGHT, NODIRECTION
+}

imageviewer-addon/src/main/java/org/tepi/imageviewer/client/ImageViewerConnector.java

@@ -30,6 +30,17 @@ public void onStateChanged(StateChangeEvent stateChangeEvent) {
 		if (getWidget().animationRunning) {
 			return;
 		}
+
+		/*
+		 * If the direction changed then move the images and signal the server the movement finished.
+		 * Skip the rest to prevent the re-rendering of all images.
+		 */
+		if (stateChangeEvent.hasPropertyChanged("direction") && !Directions.NODIRECTION.equals(getState().direction)) {
+			getWidget().move(getState().direction);
+			this.moveFinished();
+			return;
+		}
+
 		getWidget().mouseOverEffects = getState().mouseOverEffects;
 		getWidget().amountOfImages = getState().imageCount;
 		getWidget().centerImageIndex = getState().centerImageIndex;
@@ -73,4 +84,11 @@ public void layout() {
 	public void centerImageSelected(int imageIndex) {
 		rpc.centerImageSelected(imageIndex);
 	}
+
+	/**
+	 * makes and rpc call to signal that the movement is finished
+	 */
+	private void moveFinished() {
+        rpc.moveFinished();
+    }
 }

imageviewer-addon/src/main/java/org/tepi/imageviewer/client/ImageViewerServerRpc.java

@@ -5,4 +5,6 @@
 public interface ImageViewerServerRpc extends ServerRpc {
 
 	public void centerImageSelected(int newCenterImageIndex);
+
+	public void moveFinished();
 }

imageviewer-addon/src/main/java/org/tepi/imageviewer/client/ImageViewerState.java

@@ -28,4 +28,6 @@ public class ImageViewerState extends TabIndexState {
 	public boolean mouseOverEffects;
 	/** Amount of images added to the viewer */
 	public int imageCount;
+	/** Move Direction */
+	public Directions direction = Directions.NODIRECTION;
 }

imageviewer-addon/src/main/java/org/tepi/imageviewer/client/VImageViewer.java

@@ -334,6 +334,20 @@ void fixSideImageCount() {
         }
     }
 
+    /**
+     * Moves the current image one step left or right. Animates the movement if animations are enabled.
+     * 
+     * @param direction -
+     */
+    public void move(Directions direction) {
+        if (direction.equals(Directions.LEFT)) {
+            moveImages(true);
+        }
+        else {
+            moveImages(false);
+        }
+    }
+
     /**
      * Moves the image set one step left or right. Animates the movement if
      * animations are enabled.

imageviewer-demo/src/main/java/org/tepi/imageviewer/demo/ImageViewerDemoUI.java

@@ -7,16 +7,19 @@
 
 import org.tepi.imageviewer.ImageViewer;
 import org.tepi.imageviewer.ImageViewer.ImageSelectionListener;
+import org.tepi.imageviewer.client.Directions;
 
 import com.vaadin.annotations.Theme;
 import com.vaadin.annotations.Title;
 import com.vaadin.annotations.VaadinServletConfiguration;
+import com.vaadin.icons.VaadinIcons;
 import com.vaadin.server.Resource;
 import com.vaadin.server.ThemeResource;
 import com.vaadin.server.VaadinRequest;
 import com.vaadin.server.VaadinServlet;
 import com.vaadin.shared.ui.ContentMode;
 import com.vaadin.ui.Alignment;
+import com.vaadin.ui.Button;
 import com.vaadin.ui.CheckBox;
 import com.vaadin.ui.HorizontalLayout;
 import com.vaadin.ui.Label;
@@ -192,6 +195,18 @@ private Layout createControls() {
 		selectedImage.setWidth("50px");
 		hl.addComponent(selectedImage);
 		hl.setComponentAlignment(selectedImage, Alignment.BOTTOM_CENTER);
+
+		Button moveLeft = new Button(VaadinIcons.ARROW_LEFT);
+		moveLeft.setDescription("Move image left");
+		moveLeft.addClickListener(event -> this.imageViewer.move(Directions.LEFT));
+		hl.addComponent(moveLeft);
+		hl.setComponentAlignment(moveLeft, Alignment.BOTTOM_CENTER);
+
+		Button moveRight = new Button(VaadinIcons.ARROW_RIGHT);
+		moveRight.setDescription("Move image right");
+		moveRight.addClickListener(event -> this.imageViewer.move(Directions.RIGHT));
+		hl.addComponent(moveRight);
+		hl.setComponentAlignment(moveRight, Alignment.BOTTOM_CENTER);
 
 		return hl;
 	}