Back button now returns to library. Closes #252

app/src/main/java/eu/kanade/tachiyomi/ui/main/MainActivity.kt

@@ -39,7 +39,7 @@ class MainActivity : BaseActivity() {
         supportActionBar?.setHomeAsUpIndicator(R.drawable.ic_menu_white_24dp)
 
         if (Build.VERSION.SDK_INT >= 21) {
-            window.statusBarColor = android.R.color.transparent;
+            window.statusBarColor = android.R.color.transparent
         }
 
         // Set behavior of Navigation drawer
@@ -73,6 +73,16 @@ class MainActivity : BaseActivity() {
         return true
     }
 
+    override fun onBackPressed() {
+        supportFragmentManager.findFragmentById(R.id.frame_container)?.let {
+            if (it !is LibraryFragment) {
+                setFragment(LibraryFragment.newInstance())
+            } else {
+                super.onBackPressed()
+            }
+        } ?: super.onBackPressed()
+    }
+
     fun setFragment(fragment: Fragment) {
         supportFragmentManager.beginTransaction()
                 .replace(R.id.frame_container, fragment)