FileDownloader for starting downloads with any component (#9524)

* Based on patch by Pekka Hyvönen

Change-Id: I9263078ffc624f9cabec6c25264920dfdb430efe

1 files changed, 61 insertions, 0 deletions

diff --git a/client/src/com/vaadin/client/extensions/FileDownloaderConnector.java b/client/src/com/vaadin/client/extensions/FileDownloaderConnector.java
new file mode 100644
index 0000000000..d76efcc046
--- /dev/null
+++ b/client/src/com/vaadin/client/extensions/FileDownloaderConnector.java
@@ -0,0 +1,61 @@
+package com.vaadin.client.extensions;
+
+import com.google.gwt.dom.client.Document;
+import com.google.gwt.dom.client.IFrameElement;
+import com.google.gwt.dom.client.Style;
+import com.google.gwt.dom.client.Style.Unit;
+import com.google.gwt.dom.client.Style.Visibility;
+import com.google.gwt.event.dom.client.ClickEvent;
+import com.google.gwt.event.dom.client.ClickHandler;
+import com.google.gwt.user.client.ui.RootPanel;
+import com.google.gwt.user.client.ui.Widget;
+import com.vaadin.client.ComponentConnector;
+import com.vaadin.client.ServerConnector;
+import com.vaadin.server.FileDownloader;
+import com.vaadin.shared.ui.Connect;
+
+@Connect(FileDownloader.class)
+public class FileDownloaderConnector extends AbstractExtensionConnector
+        implements ClickHandler {
+
+    private IFrameElement iframe;
+
+    @Override
+    protected void extend(ServerConnector target) {
+        final Widget downloadWidget = ((ComponentConnector) target).getWidget();
+
+        downloadWidget.addDomHandler(this, ClickEvent.getType());
+    }
+
+    @Override
+    public void onClick(ClickEvent event) {
+        final String url = getResourceUrl("dl");
+        if (url != null && !url.isEmpty()) {
+            if (iframe != null) {
+                // make sure it is not on dom tree already, might start
+                // multiple downloads at once
+                iframe.removeFromParent();
+            }
+            iframe = Document.get().createIFrameElement();
+
+            Style style = iframe.getStyle();
+            style.setVisibility(Visibility.HIDDEN);
+            style.setHeight(0, Unit.PX);
+            style.setWidth(0, Unit.PX);
+
+            iframe.setFrameBorder(0);
+            iframe.setTabIndex(-1);
+            iframe.setSrc(url);
+            RootPanel.getBodyElement().appendChild(iframe);
+        }
+    }
+
+    @Override
+    public void setParent(ServerConnector parent) {
+        super.setParent(parent);
+        if (parent == null) {
+            iframe.removeFromParent();
+        }
+    }
+
+}