Refresh option in the library updates tab (#606)

* Solves #550

* Make sure only refresh can only happen when pulling down at top of update library list

* Removed unused import

app/src/main/java/eu/kanade/tachiyomi/ui/recent_updates/RecentChaptersFragment.kt

@@ -5,15 +5,18 @@ import android.support.v4.app.DialogFragment
 import android.support.v7.view.ActionMode
 import android.support.v7.widget.DividerItemDecoration
 import android.support.v7.widget.LinearLayoutManager
+import android.support.v7.widget.RecyclerView
 import android.view.*
 import com.afollestad.materialdialogs.MaterialDialog
 import eu.davidea.flexibleadapter.FlexibleAdapter
 import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.data.download.model.Download
+import eu.kanade.tachiyomi.data.library.LibraryUpdateService
 import eu.kanade.tachiyomi.ui.base.adapter.FlexibleViewHolder
 import eu.kanade.tachiyomi.ui.base.fragment.BaseRxFragment
 import eu.kanade.tachiyomi.ui.main.MainActivity
 import eu.kanade.tachiyomi.ui.reader.ReaderActivity
+import eu.kanade.tachiyomi.util.toast
 import eu.kanade.tachiyomi.widget.DeletingChaptersDialog
 import kotlinx.android.synthetic.main.fragment_recent_chapters.*
 import nucleus.factory.RequiresPresenter
@@ -73,6 +76,25 @@ class RecentChaptersFragment
         adapter = RecentChaptersAdapter(this)
         recycler.adapter = adapter
 
+        recycler.addOnScrollListener(object : RecyclerView.OnScrollListener() {
+            override fun onScrollStateChanged(recycler: RecyclerView, newState: Int) {
+                // Disable swipe refresh when view is not at the top
+                val firstPos = (recycler.layoutManager as LinearLayoutManager)
+                        .findFirstCompletelyVisibleItemPosition()
+                swipe_refresh.isEnabled = firstPos == 0
+            }
+        })
+
+        swipe_refresh.setDistanceToTriggerSync((2 * 64 * resources.displayMetrics.density).toInt())
+        swipe_refresh.setOnRefreshListener {
+            if (!LibraryUpdateService.isRunning(activity)) {
+                LibraryUpdateService.start(activity)
+                context.toast(R.string.action_update_library)
+            }
+            // It can be a very long operation, so we disable swipe refresh and show a toast.
+            swipe_refresh.isRefreshing = false
+        }
+
         // Update toolbar text
         setToolbarTitle(R.string.label_recent_updates)
     }

app/src/main/res/layout/fragment_recent_chapters.xml

@@ -1,9 +1,11 @@
 <?xml version="1.0" encoding="utf-8"?>
-<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
+
+<android.support.v4.widget.SwipeRefreshLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
+    android:id="@+id/swipe_refresh"
     android:layout_width="match_parent"
-                android:layout_height="match_parent"
+    android:layout_height="match_parent">
-                android:orientation="vertical">
 
     <android.support.v7.widget.RecyclerView
         android:id="@+id/recycler"
@@ -14,4 +16,4 @@
 
     </android.support.v7.widget.RecyclerView>
 
-</RelativeLayout>
+</android.support.v4.widget.SwipeRefreshLayout>