Added Kotlin support, MultiDex, refactoring.

- Added Kotlin support to the app. Welcome, Kotlin! :)
- Added MultiDex support. We finally hit 64K methods!
- Refactored BaseFragment. Moved EditModeListener and
  related interfaces to BaseMediaGridFragment for easier
  extension of Media Grid fragments.
- Removed unnecessary listener setters from MainActivity,
  we can use onAttach for these.
- Fixes crash and behavior #590

app/build.gradle

@@ -1,9 +1,11 @@
 apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
 
 repositories {
     maven { url  "http://dl.bintray.com/dasar/maven" }
     maven { url "https://s3.amazonaws.com/repo.commonsware.com" }
     maven { url "https://jitpack.io" }
+    mavenCentral()
 }
 
 
@@ -16,6 +18,8 @@ android {
         versionName "v0.7-alpha-2"
         versionCode 16
         vectorDrawables.useSupportLibrary = true
+
+        multiDexEnabled true
     }
 
     lintOptions {
@@ -132,6 +136,8 @@ dependencies {
     debugImplementation 'com.squareup.leakcanary:leakcanary-android:1.5.4'
     releaseImplementation 'com.squareup.leakcanary:leakcanary-android-no-op:1.5.4'
 
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+    implementation 'com.android.support:multidex:1.0.3'
 
     // TODO check them out
     implementation 'com.turingtechnologies.materialscrollbar:lib:10.0.3'

app/src/main/java/org/horaapps/leafpic/App.java

@@ -1,6 +1,6 @@
 package org.horaapps.leafpic;
 
-import android.app.Application;
+import android.support.multidex.MultiDexApplication;
 
 import com.mikepenz.community_material_typeface_library.CommunityMaterial;
 import com.mikepenz.fontawesome_typeface_library.FontAwesome;
@@ -15,7 +15,7 @@ import org.horaapps.leafpic.util.preferences.Prefs;
 /**
  * Created by dnld on 28/04/16.
  */
-public class App extends Application {
+public class App extends MultiDexApplication {
 
     private static App mInstance;
 

app/src/main/java/org/horaapps/leafpic/activities/MainActivity.java

@@ -118,7 +118,7 @@ public class MainActivity extends SharedMediaActivity implements
             return;
         }
 
-        /** We have some instance state */
+        /* We have some instance state */
         restoreState(savedInstanceState);
 
         switch (fragmentMode) {
@@ -126,21 +126,13 @@ public class MainActivity extends SharedMediaActivity implements
             case FragmentMode.MODE_MEDIA:
                 rvMediaFragment = (RvMediaFragment) getSupportFragmentManager().findFragmentByTag(RvMediaFragment.TAG);
                 rvMediaFragment.setListener(this);
-                rvMediaFragment.setEditModeListener(this);
-                rvMediaFragment.setNothingToShowListener(this);
                 break;
 
             case FragmentMode.MODE_ALBUMS:
                 albumsFragment = (AlbumsFragment) getSupportFragmentManager().findFragmentByTag(AlbumsFragment.TAG);
-                albumsFragment.setListener(this);
-                albumsFragment.setEditModeListener(this);
-                albumsFragment.setNothingToShowListener(this);
                 break;
 
             case FragmentMode.MODE_TIMELINE:
-                TimelineFragment timelineFragment = (TimelineFragment) getSupportFragmentManager().findFragmentByTag(TimelineFragment.TAG);
-                timelineFragment.setEditModeListener(this);
-                timelineFragment.setNothingToShowListener(this);
                 setupUiForTimeline();
         }
     }
@@ -155,9 +147,6 @@ public class MainActivity extends SharedMediaActivity implements
 
     private void initAlbumsFragment() {
         albumsFragment = new AlbumsFragment();
-        albumsFragment.setListener(this);
-        albumsFragment.setEditModeListener(this);
-        albumsFragment.setNothingToShowListener(this);
     }
 
     @Override
@@ -185,8 +174,6 @@ public class MainActivity extends SharedMediaActivity implements
         lockNavigationDrawer();
 
         rvMediaFragment.setListener(this);
-        rvMediaFragment.setEditModeListener(this);
-        rvMediaFragment.setNothingToShowListener(this);
 
         getSupportFragmentManager()
                 .beginTransaction()
@@ -200,9 +187,6 @@ public class MainActivity extends SharedMediaActivity implements
 
         fragmentMode = FragmentMode.MODE_TIMELINE;
 
-        fragment.setEditModeListener(this);
-        fragment.setNothingToShowListener(this);
-
         getSupportFragmentManager()
                 .beginTransaction()
                 .replace(R.id.content, fragment, TimelineFragment.TAG)

app/src/main/java/org/horaapps/leafpic/fragments/AlbumsFragment.java

@@ -60,7 +60,7 @@ import jp.wasabeef.recyclerview.animators.LandingAnimator;
  * Created by dnld on 3/13/17.
  */
 
-public class AlbumsFragment extends BaseFragment {
+public class AlbumsFragment extends BaseMediaGridFragment {
 
     public static final String TAG = "AlbumsFragment";
 
@@ -78,10 +78,6 @@ public class AlbumsFragment extends BaseFragment {
         void onAlbumClick(Album album);
     }
 
-    public void setListener(AlbumClickListener clickListener) {
-        this.listener = clickListener;
-    }
-
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -92,6 +88,7 @@ public class AlbumsFragment extends BaseFragment {
     @Override
     public void onAttach(Context context) {
         super.onAttach(context);
+        if (context instanceof AlbumClickListener) listener = (AlbumClickListener) context;
     }
 
     @Override

app/src/main/java/org/horaapps/leafpic/fragments/BaseFragment.java

@@ -1,33 +1,22 @@
 package org.horaapps.leafpic.fragments;
 
+import android.content.Context;
 
-import org.horaapps.leafpic.items.ActionsListener;
-import org.horaapps.liz.Themed;
 import org.horaapps.liz.ThemedFragment;
 
 /**
- * Created by dnld on 4/3/17.
+ * Base Fragment for abstraction logic.
  */
+public abstract class BaseFragment extends ThemedFragment {
 
-public abstract class BaseFragment extends ThemedFragment implements IFragment, Themed, ActionsListener {
-
-    private EditModeListener editModeListener;
     private NothingToShowListener nothingToShowListener;
 
-    public boolean onBackPressed(){
-        if (editMode()){
-            clearSelected();
-            return true;
-        }
-        return false;
-    }
+    @Override
+    public void onAttach(Context context) {
+        super.onAttach(context);
 
-    public EditModeListener getEditModeListener() {
-        return editModeListener;
-    }
-
-    public void setEditModeListener(EditModeListener editModeListener) {
-        this.editModeListener = editModeListener;
+        if (context instanceof NothingToShowListener)
+            nothingToShowListener = (NothingToShowListener) context;
     }
 
     public NothingToShowListener getNothingToShowListener() {

app/src/main/java/org/horaapps/leafpic/fragments/BaseMediaFragment.java

@@ -7,12 +7,11 @@ import android.view.View;
 
 import org.horaapps.leafpic.data.Media;
 import org.horaapps.liz.ThemeHelper;
-import org.horaapps.liz.ThemedFragment;
 
 /**
  * A Base Fragment for showing Media.
  */
-public abstract class BaseMediaFragment extends ThemedFragment {
+public abstract class BaseMediaFragment extends BaseFragment {
 
     private static final String ARGS_MEDIA = "args_media";
 

app/src/main/java/org/horaapps/leafpic/fragments/BaseMediaGridFragment.kt

@@ -0,0 +1,25 @@
+package org.horaapps.leafpic.fragments
+
+import android.content.Context
+
+import org.horaapps.leafpic.items.ActionsListener
+
+/**
+ * Base class for fragments showing any kind of Media in a Grid fashion.
+ *
+ * Allows selection, multiple select Context Menus, etc.
+ */
+abstract class BaseMediaGridFragment : BaseFragment(), IFragment, ActionsListener {
+
+    var editModeListener: EditModeListener? = null
+
+    override fun onAttach(context: Context?) {
+        super.onAttach(context)
+        if (context is EditModeListener) editModeListener = context
+    }
+
+    fun onBackPressed() = when (editMode()) {
+        true -> clearSelected()
+        false -> false
+    }
+}

app/src/main/java/org/horaapps/leafpic/fragments/RvMediaFragment.java

@@ -79,7 +79,7 @@ import jp.wasabeef.recyclerview.animators.LandingAnimator;
  * Created by dnld on 3/13/17.
  */
 
-public class RvMediaFragment extends BaseFragment {
+public class RvMediaFragment extends BaseMediaGridFragment {
 
     public static final String TAG = "RvMediaFragment";
     private static final String BUNDLE_ALBUM = "album";

app/src/main/java/org/horaapps/leafpic/timeline/TimelineFragment.java

@@ -25,7 +25,7 @@ import org.horaapps.leafpic.data.provider.CPHelper;
 import org.horaapps.leafpic.data.sort.MediaComparators;
 import org.horaapps.leafpic.data.sort.SortingMode;
 import org.horaapps.leafpic.data.sort.SortingOrder;
-import org.horaapps.leafpic.fragments.BaseFragment;
+import org.horaapps.leafpic.fragments.BaseMediaGridFragment;
 import org.horaapps.leafpic.interfaces.MediaClickListener;
 import org.horaapps.leafpic.util.DeviceUtils;
 import org.horaapps.leafpic.util.preferences.Defaults;
@@ -42,7 +42,7 @@ import io.reactivex.schedulers.Schedulers;
 /**
  * Fragment which shows the Timeline.
  */
-public class TimelineFragment extends BaseFragment {
+public class TimelineFragment extends BaseMediaGridFragment {
 
     public static final String TAG = "TimelineFragment";
 

build.gradle

@@ -1,6 +1,8 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 
 buildscript {
+    ext.kotlin_version = '1.2.41'
+
     repositories {
         jcenter()
         maven {
@@ -9,7 +11,9 @@ buildscript {
         google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.1.2'
+
+        classpath 'com.android.tools.build:gradle:3.1.3'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
 
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files