Make back behaviour work better for manage repos/installed apps/search.

app/src/main/AndroidManifest.xml

@@ -301,7 +301,10 @@
             android:name=".AppUpdateStatusService"
             android:exported="false" />
 
-        <activity android:name=".views.main.MainActivity">
+        <activity
+            android:name=".views.main.MainActivity"
+            android:launchMode="singleTop"
+            android:windowSoftInputMode="adjustResize">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 

app/src/main/java/org/fdroid/fdroid/views/main/MainActivity.java

@@ -6,7 +6,7 @@ import android.content.Intent;
 import android.net.Uri;
 import android.os.Bundle;
 import android.support.annotation.NonNull;
-import android.support.design.widget.BottomNavigationView;
+import android.support.annotation.Nullable;
 import android.support.v7.app.AppCompatActivity;
 import android.support.v7.widget.LinearLayoutManager;
 import android.text.TextUtils;
@@ -14,6 +14,8 @@ import android.view.MenuItem;
 import android.widget.Toast;
 import android.support.v7.widget.RecyclerView;
 
+import com.ittianyu.bottomnavigationviewex.BottomNavigationViewEx;
+
 import org.fdroid.fdroid.AppDetails;
 import org.fdroid.fdroid.AppDetails2;
 import org.fdroid.fdroid.FDroidApp;
@@ -42,7 +44,7 @@ import org.fdroid.fdroid.views.swap.SwapWorkflowActivity;
  *  When switching from one screen to the next, we stay within this activity. The new screen will
  *  get inflated (if required)
  */
-public class MainActivity extends AppCompatActivity implements BottomNavigationView.OnNavigationItemSelectedListener {
+public class MainActivity extends AppCompatActivity implements BottomNavigationViewEx.OnNavigationItemSelectedListener {
 
     private static final String TAG = "MainActivity";
 
@@ -52,14 +54,17 @@ public class MainActivity extends AppCompatActivity implements BottomNavigationV
 
     private static final String ACTION_ADD_REPO = "org.fdroid.fdroid.MainActivity.ACTION_ADD_REPO";
 
+    private static final String STATE_SELECTED_MENU_ID = "selectedMenuId";
+
     private static final int REQUEST_SWAP = 3;
 
     private RecyclerView pager;
     private MainViewAdapter adapter;
-    private BottomNavigationView bottomNavigation;
+    private BottomNavigationViewEx bottomNavigation;
+    private int selectedMenuId = R.id.whats_new;
 
     @Override
-    protected void onCreate(Bundle savedInstanceState) {
+    protected void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
         setContentView(R.layout.activity_main);
@@ -71,15 +76,30 @@ public class MainActivity extends AppCompatActivity implements BottomNavigationV
         pager.setLayoutManager(new NonScrollingHorizontalLayoutManager(this));
         pager.setAdapter(adapter);
 
-        bottomNavigation = (BottomNavigationView) findViewById(R.id.bottom_navigation);
+        bottomNavigation = (BottomNavigationViewEx) findViewById(R.id.bottom_navigation);
         bottomNavigation.setOnNavigationItemSelectedListener(this);
 
+        if (savedInstanceState != null) {
+            selectedMenuId = savedInstanceState.getInt(STATE_SELECTED_MENU_ID, R.id.whats_new);
+        }
+        setSelectedMenuInNav();
+
         initialRepoUpdateIfRequired();
 
         Intent intent = getIntent();
         handleSearchOrAppViewIntent(intent);
     }
 
+    @Override
+    protected void onSaveInstanceState(Bundle outState) {
+        outState.putInt(STATE_SELECTED_MENU_ID, selectedMenuId);
+        super.onSaveInstanceState(outState);
+    }
+
+    private void setSelectedMenuInNav() {
+        bottomNavigation.setCurrentItem(adapter.adapterPositionFromItemId(selectedMenuId));
+    }
+
     /**
      * The first time the app is run, we will have an empty app list. To deal with this, we will
      * attempt to update with the default repo. However, if we have tried this at least once, then
@@ -103,7 +123,8 @@ public class MainActivity extends AppCompatActivity implements BottomNavigationV
         if (getIntent().hasExtra(EXTRA_VIEW_UPDATES)) {
             getIntent().removeExtra(EXTRA_VIEW_UPDATES);
             pager.scrollToPosition(adapter.adapterPositionFromItemId(R.id.updates));
-            bottomNavigation.findViewById(R.id.updates).performClick();
+            selectedMenuId = R.id.updates;
+            setSelectedMenuInNav();
         }
 
         // AppDetails  2 and RepoDetailsActivity set different NFC actions, so reset here
@@ -131,6 +152,7 @@ public class MainActivity extends AppCompatActivity implements BottomNavigationV
     @Override
     public boolean onNavigationItemSelected(@NonNull MenuItem item) {
         pager.scrollToPosition(((MainViewAdapter) pager.getAdapter()).adapterPositionFromItemId(item.getItemId()));
+        selectedMenuId = item.getItemId();
         return true;
     }
 

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

@@ -6,7 +6,7 @@
     android:layout_width="match_parent"
     android:layout_height="match_parent">
 
-    <android.support.design.widget.BottomNavigationView
+    <com.ittianyu.bottomnavigationviewex.BottomNavigationViewEx
         android:id="@+id/bottom_navigation"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"