Changeset 38925 for main

Timestamp:

2024-04-12T22:15:35+12:00 (4 weeks ago)

Author:

anupama

Message:

I can't get the webswing JavaScript to webswing communication to work. performAction doesn't appear to get called no matter what I try. Am I supposed to register it somewhere? The documentation doesn't mention this or how it's to be done.

Location:

main/trunk/greenstone3

Files:

• src/java/org/greenstone/applet/GsdlCollageApplet/GsdlCollageApplet.java (modified) (4 diffs)
• web/interfaces/default/transform/pages/webswing-collage.xsl (modified) (4 diffs)

main/trunk/greenstone3/src/java/org/greenstone/applet/GsdlCollageApplet/GsdlCollageApplet.java

@@ -2 +2 @@
 
 import org.webswing.toolkit.api.WebswingUtil;
+import org.webswing.toolkit.api.action.WebActionEvent;
+import org.webswing.toolkit.api.action.WebActionListener;
 
 //import java.applet.Applet;
@@ -161 +163 @@
     //}
 
+    // Handle getting called by webswing JavaScript:
+    // when the user navigates away from the webswing app's web page, do cleanup
+    // https://www.webswing.org/docs/23.2/integrate/jslink.html#invoking-java-from-javascript
+    // https://vaadin.com/directory/component/webswing-vaadin1
+    org.webswing.toolkit.api.WebswingUtil.getWebswingApi().addBrowserActionListener(new org.webswing.toolkit.api.action.WebActionListener() {
+        @Override
+        public void actionPerformed(org.webswing.toolkit.api.action.WebActionEvent actionEvent) {
+            switch (actionEvent.getActionName()) {
+            case "navigatingAway":
+            // do cleanup
+            System.err.println("@@@@ In Java collage addBrowserActionListener on navigatingAway - called");
+            GsdlCollageApplet.this.stopRunning();
+            break;
+            case "testJavaCall":
+            org.webswing.toolkit.api.WebswingUtil.getWebswingApi().sendActionEvent("javaToWebswingJSConsoleLog", "GsdlCollageApplet got TEST call !!", null);
+            //WebswingUtil.getWebswingApi().sendActionEvent("@@@ javaToWebswingJSConsoleLog", "GsdlCollageApplet - testjavaCall handler got your message", null);
+            }
+        }
+        });
+    
     this.addMouseListener(new CollageMouseAdapter());
     }
@@ -724 +746 @@
         d.width = collageApp.getWidth();
         statusBar.setPreferredSize(d);
-        //statusBar.setPreferredSize(new Dimension(collageApp.getWidth(), EXTRA_HEIGHT));    
+        //statusBar.setPreferredSize(new Dimension(collageApp.getWidth(), EXTRA_HEIGHT));
         }
         
@@ -737 +759 @@
         frame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent e) {
+            // WHY doesn't javascript console log unless I prefix webswing package name??
+            //WebswingUtil.getWebswingApi().sendActionEvent("@@@ javaToWebswingJSConsoleLog", "GsdlCollageApplet - quitting now", null);
+            org.webswing.toolkit.api.WebswingUtil.getWebswingApi().sendActionEvent("javaToWebswingJSConsoleLog", "GsdlCollageApplet about to QUIT !!", null);
+            
             collageApp.showStatus("Stopping threads");
             System.err.println("\n\n*** Closing applet: stopping threads...");
             collageApp.stopRunning();
+            
             //collageApp.stop();
             //collageApp.destroy();

main/trunk/greenstone3/web/interfaces/default/transform/pages/webswing-collage.xsl

@@ -82 +82 @@
     <xsl:template name="webswing-embed-collage">
       <link rel="stylesheet" href="/webswing-server/css/style.css" />
-
       <div id="webswing-collage" class="webswing-element" data-webswing-instance="webswingInstance0" style="width: 800px; height: 400px;">
         <div id="loading" class="ws-modal-container">
@@ -131 +130 @@
              window.open(url, '_blank');
           }
+        } else if (actionName == "javaToWebswingJSConsoleLog") {
+            console.log("Got message from java:\n" + data);
         }
         
@@ -201 +202 @@
   <script data-webswing-global-var="webswing">
     <xsl:text disable-output-escaping="yes">
+
+      var doButtonClick = function() {
+      console.log("button clicked");
+          webswingInstance0.performAction({actionName: "testJavaCall"});
+      }
+      var unloaded = false;
     (function (window, document) {
         var loader = function () {
-            var baseUrl = '/webswing-server/collage';
+
+        unloaded = false; // reset state, because we are reloading the webswing app
+    
+        var baseUrl = '/webswing-server/collage';
             baseUrl = baseUrl.indexOf("/", baseUrl.length - 1) !== -1 ? baseUrl : (baseUrl + "/");
             var xmlhttp = new XMLHttpRequest();
@@ -218 +228 @@
             xmlhttp.send();
         };
+
+    var navigatingAway = function () {
+       console.log("*** navigatingAway called");
+
+       // Multiple eventlisteners are registered to call navigatingAway, as not all are 
+       // triggered in all contexts (desktop vs mobile vs older browsers)
+       // https://developer.mozilla.org/en-US/docs/Web/API/Window/unload_event
+       // We work with multiple eventlisteners to ensure we cleanup webswing collage app when
+       // user navigates away from page. But we should only do the cleanup once, even if *all*
+       // event handlers got triggered. We use the unloaded var to ensure we cleanup only once
+       if(!unloaded) {
+       if(typeof webswingInstance0.performAction === 'function') {
+              //event.preventDefault(); // if listening for beforeunload event
+              console.log("@@@@ Calling Java to stop running the webswing collage app");
+              webswingInstance0.performAction({actionName: "navigatingAway"});
+              unloaded = true;
+          console.log("@@@@ unloaded");
+          //alert("check log");
+        } else {
+            console.log("performAction method DOESN'T exist on the webswing object!");
+            }
+        } else {
+            console.log("@@@@ already unloaded.");
+        }
+
+    };
+    
         window.addEventListener ? window.addEventListener("load", loader, false) : window.attachEvent("onload", loader);
+
+    // https://developer.mozilla.org/en-US/docs/Web/API/Window/unload_event
+    // unload has been deprecated, and so we try pagehide and visibilitychange events
+    window.addEventListener ? window.addEventListener("unload", navigatingAway, false) : window.attachEvent("onunload", navigatingAway);
+    window.addEventListener ? window.addEventListener("pagehide", navigatingAway, false) : window.attachEvent("onpagehide", navigatingAway);
+    window.addEventListener ? window.addEventListener("visibilitychange", navigatingAway, false) : window.attachEvent("onvisibilitychange", navigatingAway);    
+    
     })(window, document);
     </xsl:text>
   </script>
-
-
-
+  
+ <button type="button" onclick="doButtonClick()">Click Me!</button> 
     </xsl:template>