Simple list inside fragment not populating

Question

I have started with the project Sunshine on Udacity.
I am on the very first chapter and trying to populate a listview. But my list view is not populating. Running it on the Genymotion emulator, only a blank screen is shown with the action bar.

My code:
MainActivity.java

package snehit.sunshine.app;

import android.app.Fragment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu, menu);
    return true;
}

public static class PlaceHolderFragment extends Fragment {
    @Override

    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View rootView = inflater.inflate(R.layout.fragment_main,container,false);

        String forecastArray[] = {
                "Today - Sunny - 88/63",
                "tom - Sunny - 88/63",
                "day after - Cyclone - 88/63",
                "another day - Tornadoes - 88/63",
                "One another day - Sunny - 88/63",
                "Next day - Sunny - 88/63",
                "again, next day - Sunny - 88/63"

        };

        List<String> weekForecast = new ArrayList<String>(
                Arrays.asList(forecastArray)
        );

        ArrayAdapter mForecastAdapter = new ArrayAdapter(getActivity(),R.layout.list_item_forecast, R.id.list_item_forecast_textview,weekForecast);

        ListView listview = (ListView) rootView.findViewById(R.id.listview_forecast);
        listview.setAdapter(mForecastAdapter);
        return rootView;
    }
}
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:ignore="MergeRootFrame"
    android:id="@+id/container"
    tools:context="snehit.sunshine.app.MainActivity">

</FrameLayout>

fragment_main.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:paddingLeft="64dp"
    android:paddingRight="64dp"
    android:paddingTop="16dp"
    android:paddingBottom="16dp"
    tools:context=".MainActivity$PlaceHolderFragment"
    android:layout_height="match_parent">

    <ListView
        android:layout_width="match_parent"
        android:id="@+id/listview_forecast"
        android:layout_height="match_parent" />
</FrameLayout>  

list_item_forecast.xml

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height= "wrap_content"
    android:minHeight="?android:attr/listPreferredItemHeight"
    android:gravity="center_vertical"
    android:id="@+id/list_item_forecast_textview"
    />  

I am using Android Studio 2.1(I don't know if using Eclipse would make any change...I am new to android development) The IDE does not show any errors, nor the app is crashing when it is started. I tested it on a Genymotion emulator running Marshmallow (API 23)

Answer 1

I think you forget to load fragment in FrameLayout Please try below code

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_stack_main"
    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"
    tools:context="com.mahii.notifybox.StackMainActivity">

    <FrameLayout
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</RelativeLayout>

Fragment class

public class StackFragment extends Fragment {

    ListView listview_forecast;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragment_stack, container, false);

        listview_forecast = (ListView) view.findViewById(R.id.listview_forecast);

        String forecastArray[] = {
                "Today - Sunny - 88/63",
                "tom - Sunny - 88/63",
                "day after - Cyclone - 88/63",
                "another day - Tornadoes - 88/63",
                "One another day - Sunny - 88/63",
                "Next day - Sunny - 88/63",
                "again, next day - Sunny - 88/63"

        };

        List<String> weekForecast = new ArrayList<>(
                Arrays.asList(forecastArray)
        );

        ArrayAdapter mForecastAdapter = new ArrayAdapter(getActivity(), R.layout.list_item_forecast, R.id.list_item_forecast_textview, weekForecast);
        listview_forecast.setAdapter(mForecastAdapter);

        return view;

    }
}

fragment_stack.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <ListView
        android:id="@+id/listview_forecast"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</LinearLayout>

And finally in your MainActivity

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_stack_main);

    StackFragment stackFragment = new StackFragment();
    FragmentManager fm = getSupportFragmentManager();
    FragmentTransaction ft = fm.beginTransaction();
    ft.replace(R.id.container, stackFragment, stackFragment.getClass().getName());
    ft.commit();

}

And here is the output

Answer 2

As per the code you have pasted, I cannot see the Fragment Transaction in your activity that means you have not inflated fragment into your activity. There are 2 options to it

1. You can directly inflate your PlaceHolderFragment in the xml of your acvity.
2. You can use FragmentManager to add Fragment to your Activity's view.

Please refer the link for more info: Fragment in Activity

Thanks and Regards