From 93176e2a7acae8ec640eadf62706d208c816f99f Mon Sep 17 00:00:00 2001
From: y20k <mail@y20k.org>
Date: Mon, 16 Jan 2017 15:56:58 +0100
Subject: [PATCH] tries to prevent a crash in the custom ViewPager

---
 app/build.gradle                                |  1 +
 .../java/org/y20k/trackbook/MainActivity.java   | 17 ++++++++++++++++-
 .../trackbook/layout/NonSwipeableViewPager.java | 10 +++++++---
 3 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/app/build.gradle b/app/build.gradle
index dc58494..b33c119 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -23,6 +23,7 @@ android {
 dependencies {
     compile fileTree(include: ['*.jar'], dir: 'libs')
     testCompile 'junit:junit:4.12'
+    compile 'com.android.support:support-v4:25.1.0'
     compile 'com.android.support:appcompat-v7:25.1.0'
     compile 'com.android.support:design:25.1.0'
     compile 'com.android.support:cardview-v7:25.1.0'
diff --git a/app/src/main/java/org/y20k/trackbook/MainActivity.java b/app/src/main/java/org/y20k/trackbook/MainActivity.java
index d84449a..816d11a 100644
--- a/app/src/main/java/org/y20k/trackbook/MainActivity.java
+++ b/app/src/main/java/org/y20k/trackbook/MainActivity.java
@@ -175,6 +175,17 @@ public class MainActivity extends AppCompatActivity implements TrackbookKeys {
                 startActivity(aboutIntent);
                 return true;
 
+            // CASE MY LOCATION
+            case R.id.action_bar_my_location:
+                LogHelper.v(LOG_TAG, "MainActivity: CASE MY LOCATION."); // todo remove
+                if (mSelectedTab != FRAGMENT_ID_MAP) {
+                    LogHelper.v(LOG_TAG, "MainActivity: ."); // todo remove
+                    // show map fragment
+                    mSelectedTab = FRAGMENT_ID_MAP;
+                    mViewPager.setCurrentItem(mSelectedTab);
+                }
+                return false;
+
             // CASE DEFAULT
             default:
                 return super.onOptionsItemSelected(item);
@@ -215,6 +226,9 @@ public class MainActivity extends AppCompatActivity implements TrackbookKeys {
         super.onDestroy();
         LogHelper.v(LOG_TAG, "onDestroy called.");
 
+        // reset selected tab
+        mSelectedTab = FRAGMENT_ID_MAP;
+
         // disable  broadcast receiver
         LocalBroadcastManager.getInstance(this).unregisterReceiver(mTrackingStoppedReceiver);
     }
@@ -264,7 +278,6 @@ public class MainActivity extends AppCompatActivity implements TrackbookKeys {
     }
 
 
-
     @Override
     public void onRestoreInstanceState(Bundle savedInstanceState) {
         super.onRestoreInstanceState(savedInstanceState);
@@ -321,11 +334,13 @@ public class MainActivity extends AppCompatActivity implements TrackbookKeys {
                         case FRAGMENT_ID_MAP:
                             // show the Floating Action Button
                             mFloatingActionButton.show();
+                            mSelectedTab = FRAGMENT_ID_MAP;
                             break;
                         case FRAGMENT_ID_TRACK:
                             // hide the Floating Action Button - and its sub menu
                             mFloatingActionButton.hide();
                             showFloatingActionButtonMenu(false);
+                            mSelectedTab = FRAGMENT_ID_TRACK;
                             break;
                         default:
                             // show the Floating Action Button
diff --git a/app/src/main/java/org/y20k/trackbook/layout/NonSwipeableViewPager.java b/app/src/main/java/org/y20k/trackbook/layout/NonSwipeableViewPager.java
index 2ee051b..d23664c 100644
--- a/app/src/main/java/org/y20k/trackbook/layout/NonSwipeableViewPager.java
+++ b/app/src/main/java/org/y20k/trackbook/layout/NonSwipeableViewPager.java
@@ -73,10 +73,14 @@ public class NonSwipeableViewPager extends ViewPager {
         try {
             Class<?> viewpager = ViewPager.class;
             Field scroller = viewpager.getDeclaredField("mScroller");
-            scroller.setAccessible(true);
-            scroller.set(this, new MyScroller(getContext()));
+            if (scroller != null) {
+                scroller.setAccessible(true);
+                scroller.set(this, new MyScroller(getContext()));
+            } else {
+                LogHelper.v(LOG_TAG, "Unable to get mScroller field."); // todo remove
+            }
         } catch (Exception e) {
-            LogHelper.e(LOG_TAG, "Problem accessing or modifying the mScroller field.");
+            LogHelper.e(LOG_TAG, "Problem accessing or modifying the mScroller field. Exception: " + e);
             e.printStackTrace();
         }
     }