Hiding FABs on scroll.

CHANGELOG.md

@@ -1,3 +1,7 @@
+**master**
+
+- Hiding FABs on scroll.
+
 **1.5.4.10**
 
 - Displaying a loader when "reading more" in the article viewer.

app/src/main/java/apps/amine/bou/readerforselfoss/ReaderActivity.kt

@@ -124,6 +124,14 @@ class ReaderActivity : AppCompatActivity() {
                 image.visibility = View.GONE
             }
         }
+
+        nestedScrollView.setOnScrollChangeListener(NestedScrollView.OnScrollChangeListener { _, _, scrollY, _, oldScrollY ->
+            if (scrollY > oldScrollY) {
+                fab.hide()
+            } else {
+                fab.show()
+            }
+        })
     }
 
     private fun getContentFromMercury(customTabsIntent: CustomTabsIntent, prefs: SharedPreferences) {

app/src/main/java/apps/amine/bou/readerforselfoss/SourcesActivity.kt

@@ -8,6 +8,7 @@ import android.support.v7.app.AppCompatActivity
 import android.support.v7.widget.LinearLayoutManager
 import android.support.v7.widget.RecyclerView
 import android.support.v7.widget.Toolbar
+import android.view.View
 import android.widget.Toast
 import apps.amine.bou.readerforselfoss.adapters.SourcesListAdapter
 import apps.amine.bou.readerforselfoss.api.selfoss.SelfossApi
@@ -20,6 +21,8 @@ import retrofit2.Response
 
 class SourcesActivity : AppCompatActivity() {
 
+    private lateinit var mRecyclerView: RecyclerView
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         Scoop.getInstance().apply(this)
@@ -30,10 +33,15 @@ class SourcesActivity : AppCompatActivity() {
         supportActionBar?.setDisplayShowHomeEnabled(true)
     }
 
+    override fun onStop() {
+        super.onStop()
+        mRecyclerView.clearOnScrollListeners()
+    }
+
     override fun onResume() {
         super.onResume()
         val mFab: FloatingActionButton = findViewById(R.id.fab)
-        val mRecyclerView: RecyclerView = findViewById(R.id.activity_sources)
+        mRecyclerView = findViewById(R.id.activity_sources)
         val mLayoutManager = LinearLayoutManager(this)
 
         val prefs = PreferenceManager.getDefaultSharedPreferences(this)

app/src/main/java/apps/amine/bou/readerforselfoss/utils/ScrollAwareFABBehavior.kt

@@ -0,0 +1,33 @@
+package apps.amine.bou.readerforselfoss.utils
+
+import android.content.Context
+import android.support.design.widget.CoordinatorLayout
+import android.support.design.widget.FloatingActionButton
+import android.util.AttributeSet
+import android.view.View
+
+class ScrollAwareFABBehavior(context: Context, attrs: AttributeSet) : CoordinatorLayout.Behavior<FloatingActionButton>() {
+
+    override fun onStartNestedScroll(coordinatorLayout: CoordinatorLayout, child: FloatingActionButton,
+                                     directTargetChild: View, target: View, nestedScrollAxes: Int): Boolean {
+        return true
+    }
+
+    override fun onNestedScroll(coordinatorLayout: CoordinatorLayout,
+                                child: FloatingActionButton,
+                                target: View, dxConsumed: Int, dyConsumed: Int,
+                                dxUnconsumed: Int, dyUnconsumed: Int) {
+        super.onNestedScroll(coordinatorLayout, child, target, dxConsumed, dyConsumed, dxUnconsumed, dyUnconsumed)
+        if (dyConsumed > 0 && child.visibility == View.VISIBLE) {
+            child.hide(object : FloatingActionButton.OnVisibilityChangedListener() {
+                override fun onHidden(fab: FloatingActionButton?) {
+                    super.onHidden(fab)
+                    fab!!.visibility = View.INVISIBLE
+                }
+            })
+
+        } else if (dyConsumed < 0 && child.visibility != View.VISIBLE) {
+            child.show()
+        }
+    }
+}

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

@@ -43,5 +43,6 @@
         android:layout_alignParentEnd="true"
         android:layout_marginBottom="16dp"
         android:layout_marginEnd="16dp"
-        android:layout_marginRight="16dp" />
+        android:layout_marginRight="16dp"
+        app:layout_behavior="apps.amine.bou.readerforselfoss.utils.ScrollAwareFABBehavior" />
 </android.support.design.widget.CoordinatorLayout>