Implemented Pull2Refresh in the KeyListFragment

Added KeyUpdateHelper and extended ProviderHelper for better fingerprint collection
Added a class for handling the list in the swipe2refresh layout that prevents scrolling bugs
Added Pull2Refresh to the KeyListFragment

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/KeyListFragment.java

@@ -35,6 +35,7 @@ import android.support.v4.content.CursorLoader;
 import android.support.v4.content.Loader;
 import android.support.v4.view.MenuItemCompat;
 import android.support.v4.widget.CursorAdapter;
+import android.support.v4.widget.SwipeRefreshLayout;
 import android.support.v7.app.ActionBarActivity;
 import android.support.v7.widget.SearchView;
 import android.view.ActionMode;
@@ -55,9 +56,12 @@ import android.widget.TextView;
 import org.sufficientlysecure.keychain.Constants;
 import org.sufficientlysecure.keychain.R;
 import org.sufficientlysecure.keychain.helper.ExportHelper;
+import org.sufficientlysecure.keychain.helper.KeyUpdateHelper;
 import org.sufficientlysecure.keychain.pgp.KeyRing;
 import org.sufficientlysecure.keychain.provider.KeychainContract.KeyRings;
+import org.sufficientlysecure.keychain.service.KeychainIntentServiceHandler;
 import org.sufficientlysecure.keychain.ui.dialog.DeleteKeyDialogFragment;
+import org.sufficientlysecure.keychain.ui.widget.ListAwareSwipeRefreshLayout;
 import org.sufficientlysecure.keychain.util.Highlighter;
 import org.sufficientlysecure.keychain.util.Log;
 import org.sufficientlysecure.keychain.util.Notify;
@@ -74,10 +78,11 @@ import se.emilsjolander.stickylistheaders.StickyListHeadersListView;
  */
 public class KeyListFragment extends LoaderFragment
         implements SearchView.OnQueryTextListener, AdapterView.OnItemClickListener,
-        LoaderManager.LoaderCallbacks<Cursor> {
+        LoaderManager.LoaderCallbacks<Cursor>, SwipeRefreshLayout.OnRefreshListener {
 
     private KeyListAdapter mAdapter;
     private StickyListHeadersListView mStickyList;
+    private ListAwareSwipeRefreshLayout mSwipeRefreshLayout;
 
     // saves the mode object for multiselect, needed for reset at some point
     private ActionMode mActionMode = null;
@@ -120,6 +125,15 @@ public class KeyListFragment extends LoaderFragment
             }
         });
 
+        mSwipeRefreshLayout = (ListAwareSwipeRefreshLayout) view.findViewById(R.id.key_list_swipe_container);
+        mSwipeRefreshLayout.setOnRefreshListener(this);
+        mSwipeRefreshLayout.setColorScheme(
+                R.color.android_purple_dark,
+                R.color.android_purple_light,
+                R.color.android_purple_dark,
+                R.color.android_purple_light);
+        mSwipeRefreshLayout.setStickyListHeadersListView(mStickyList);
+
         return root;
     }
 
@@ -690,4 +704,16 @@ public class KeyListFragment extends LoaderFragment
 
     }
 
+    /**
+     * Implements OnRefreshListener for drag-to-refresh
+     */
+    public void onRefresh() {
+        KeyUpdateHelper updateHelper = new KeyUpdateHelper();
+        KeychainIntentServiceHandler finishedHandler = new KeychainIntentServiceHandler(getActivity()) {
+            public void handleMessage(Message message) {
+                mSwipeRefreshLayout.setRefreshing(false);
+            }
+        };
+        updateHelper.updateAllKeys(getActivity(), finishedHandler);
+    }
 }

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/widget/ListAwareSwipeRefreshLayout.java

@@ -0,0 +1,49 @@
+package org.sufficientlysecure.keychain.ui.widget;
+
+import android.content.Context;
+import android.support.v4.widget.SwipeRefreshLayout;
+import android.util.AttributeSet;
+
+import se.emilsjolander.stickylistheaders.StickyListHeadersListView;
+
+public class ListAwareSwipeRefreshLayout extends SwipeRefreshLayout {
+
+    /**
+     * A StickyListHeadersListView whose parent view is this SwipeRefreshLayout
+     */
+    private StickyListHeadersListView mStickyListHeadersListView;
+
+    public ListAwareSwipeRefreshLayout(Context context) {
+        super(context);
+    }
+
+    public ListAwareSwipeRefreshLayout(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public void setStickyListHeadersListView(StickyListHeadersListView stickyListHeadersListView) {
+        mStickyListHeadersListView = stickyListHeadersListView;
+    }
+
+    @Override
+    public boolean canChildScrollUp() {
+        if (mStickyListHeadersListView != null) {
+            // In order to scroll a StickyListHeadersListView up:
+            // Firstly, the wrapped ListView must have at least one item
+            return (mStickyListHeadersListView.getListChildCount() > 0) &&
+                    // And then, the first visible item must not be the first item
+                    ((mStickyListHeadersListView.getFirstVisiblePosition() > 0) ||
+                            // If the first visible item is the first item,
+                            // (we've reached the first item)
+                            // make sure that its top must not cross over the padding top of the wrapped ListView
+                            (mStickyListHeadersListView.getListChildAt(0).getTop() < 0));
+
+            // If the wrapped ListView is empty or,
+            // the first item is located below the padding top of the wrapped ListView,
+            // we can allow performing refreshing now
+        } else {
+            // Fall back to default implementation
+            return super.canChildScrollUp();
+        }
+    }
+}