android ListView doesn't show up on screen. no errors

I am working on an Android v22 code. For some reason the List View simply doesn't show up and I have been trying but caot figure out why. There are no errors. Just a blank screen. I have tried debugging it and it goes smoothly upto the last line allianceActivityList.setAdapter(adapter); At that point, hitting F7 takes me inside the ListView.java file, in the code

public void setAdapter(ListAdapter adapter) {
    if (mAdapter != null && mDataSetObserver != null) {
        mAdapter.unregisterDataSetObserver(mDataSetObserver);
    }

I did notice that 'mAdapter' and 'mDataSetObserver' were both highlighted in red. But I don't know if it's normal behaviour.

The code in Main activity that calls listview is below.

public class PlayerGrowthActivity extends AppCompatActivity {

public static final String LOGTAG = "LnK ActvPlayerGrowth: ";
private int readJSONActivityFile = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_player_growth);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
        }
    });


    FileIO fileIO = new FileIO();
    ActivityTrackerDataSource activityTrackerDataSource = new ActivityTrackerDataSource(PlayerGrowthActivity.this);
    Integer allianceID = 3732;
    //allianceID = -1;  //dont reload the json files to sqlite table


    if (readJSONActivityFile == 1){
        try {
            fileIO.ReadJSONFile(PlayerGrowthActivity.this, "activity_tracker1.json" );
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    ArrayList<String[]> playerActivity = activityTrackerDataSource.getActivityPlayers(allianceID);
    ListView allianceActivityList = (ListView) findViewById(R.id.listViewPlayerActivity);

    ListAdapter adapter = new ActivityTableAdapter(PlayerGrowthActivity.this, playerActivity);
    allianceActivityList.setAdapter(adapter);

activity_player_growth.xml

<?xml version="1.0" encoding="utf-8"?>

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/MyTheme.AppBarOverlay">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:popupTheme="@style/MyTheme.PopupOverlay" />

</android.support.design.widget.AppBarLayout>

<include layout="@layout/content_player_growth" />

<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/fab_margin"
    android:src="@android:drawable/ic_dialog_email" />

content_player_growth.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="app.monty.lordsknightsapp.PlayerGrowthActivity"
tools:showIn="@layout/activity_player_growth">

<LinearLayout
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentTop="true"
    android:layout_alignParentStart="true"
    android:id="@+id/linearLayout">
        <LinearLayout
            android:orientation="vertical"
            android:layout_width="fill_parent"
            android:layout_height="match_parent"
            android:id="@+id/LinLayoutAllianceSelect">
            <Spier
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:id="@+id/spinAllianceName"

                android:spierMode="dropdown" />
        </LinearLayout>
        <LinearLayout
            android:orientation="vertical"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_marginStart="223dp"
            android:id="@+id/LinLayoutOptions">

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textAppearance="?android:attr/textAppearanceMedium"
                android:text="Medium Text"
                android:id="@+id/textView"
                android:layout_gravity="end" />
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textAppearance="?android:attr/textAppearanceMedium"
                android:text="Medium Text"
                android:id="@+id/textView2"
                android:layout_gravity="end" />
        </LinearLayout>
        <LinearLayout
            android:orientation="vertical"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_marginStart="212dp">
            <RadioButton
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="New RadioButton"
                android:id="@+id/radioButton"
                android:layout_gravity="end" />
            <CheckBox
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="New CheckBox"
                android:id="@+id/checkBox"
                android:layout_marginStart="212dp" />
        </LinearLayout>
    </LinearLayout>
    <ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/listViewPlayerActivity">
    </ListView> 
</RelativeLayout>

It might be helpful to mention that this is a new screen/feature. The old screens/features show lists successfully. Also, this is the first time, I used Android's built in drag and drop to create the layout files. not sure if that is causing the unexpected behavior.