add a Fab button

app/build.gradle

@@ -29,6 +29,7 @@ dependencies {
     testCompile 'junit:junit:4.12'
     compile 'com.android.support:appcompat-v7:23.4.0'
     compile 'com.android.support:recyclerview-v7:23.4.0'
+    compile 'com.android.support:design:23.4.0'
     compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
 }
 

app/src/main/kotlin/com/simplemobiletools/applauncher/activities/MainActivity.kt

@@ -27,6 +27,7 @@ class MainActivity : SimpleActivity() {
                 startActivity(viewIntent("https://play.google.com/store/apps/details?id=" + it.pkgName))
             }
         }
+        fab.setOnClickListener { }
     }
 
     override fun onCreateOptionsMenu(menu: Menu?): Boolean {

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

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<RelativeLayout
+<android.support.design.widget.CoordinatorLayout
-    android:id="@+id/grid_holder"
+    android:id="@+id/coordinator_layout"
     xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     android:layout_width="match_parent"
@@ -16,4 +16,12 @@
         app:layoutManager="android.support.v7.widget.GridLayoutManager"
         app:spanCount="@integer/columns"/>
 
-</RelativeLayout>
+    <android.support.design.widget.FloatingActionButton
+        android:id="@+id/fab"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="bottom|end"
+        android:layout_margin="@dimen/activity_margin"
+        android:src="@mipmap/plus"/>
+
+</android.support.design.widget.CoordinatorLayout>