android: reposition the viewport to the cursor at key event

Change-Id: I9b18001d0629e203bee41ebbf4a3bd57adfea88e

android/experimental/LOAndroid3/src/java/org/libreoffice/InvalidationHandler.java

 package org.libreoffice;
 
 import android.content.Intent;
+import android.graphics.PointF;
 import android.graphics.RectF;
 import android.net.Uri;
 
@@ -19,6 +20,7 @@ public class InvalidationHandler implements Document.MessageCallback {
     private static String LOGTAG = InvalidationHandler.class.getSimpleName();
     private final DocumentOverlay mDocumentOverlay;
     private OverlayState mState;
+    private boolean mKeyEvent = false;
 
     public InvalidationHandler(LibreOfficeMainActivity mainActivity) {
         mDocumentOverlay = mainActivity.getDocumentOverlay();
@@ -150,6 +152,12 @@ public class InvalidationHandler implements Document.MessageCallback {
             mDocumentOverlay.positionCursor(cursorRectangle);
             mDocumentOverlay.positionHandle(SelectionHandle.HandleType.MIDDLE, cursorRectangle);
 
+            if (mKeyEvent) {
+                PointF point = new PointF(cursorRectangle.centerX(), cursorRectangle.centerY());
+                LOKitShell.moveViewportTo(point, null);
+                mKeyEvent = false;
+            }
+
             if (mState == OverlayState.TRANSITION || mState == OverlayState.CURSOR) {
                 changeStateTo(OverlayState.CURSOR);
             }
@@ -352,6 +360,10 @@ public class InvalidationHandler implements Document.MessageCallback {
         return mState;
     }
 
+    public void keyEvent() {
+        mKeyEvent = true;
+    }
+
     public enum OverlayState {
         /**
          * State where the overlay is empty

android/experimental/LOAndroid3/src/java/org/libreoffice/LOKitThread.java

@@ -271,6 +271,7 @@ public class LOKitThread extends Thread {
         if (mTileProvider == null) {
             return;
         }
+        mInvalidationHandler.keyEvent();
         mTileProvider.sendKeyEvent(keyEvent);
     }