Attempting to Populate ListView With Custom Adapter

Question

I am trying to populate a ListView in a fragment named DrivingLog. I made a custom adapter that converts strings of a specific format to a view called drivinglog_list_item.xml.

DrivingLog.java

package com.example.drivinglessona3;
import android.content.Context;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

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



public class DrivingLog extends Fragment{
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        super.onCreateView(inflater, container, savedInstanceState);
        String[] sampleData = {"02/27/2017,1.2,Residential,Clear",
                "02/25/2017,0.5,Residential,Raining",
                "02/20/2017,0.3,Highway,Snow/Ice"};
        List<String> sampleDataList = new ArrayList<String>(Arrays.asList(sampleData));
        View rootView = inflater.inflate(R.layout.fragment_driving_log, container, false);
        DrivingLogAdapter adapter = new DrivingLogAdapter(getContext(), R.layout.drivinglog_list_item, sampleData);
        ListView listview = (ListView) rootView.findViewById(R.id.listView);
        listview.setAdapter(adapter);
        return rootView;
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        getActivity().setTitle("Driving Log");
    }

    public class DrivingLogAdapter extends ArrayAdapter<String[]> {
        private final Context context;
        private final String[] values;

        public DrivingLogAdapter(Context context, int layoutId, String[] values)
        {
            super(context, layoutId);
            this.context = context;
            this.values = values;
        }

        @NonNull
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            LayoutInflater inflater = (LayoutInflater) context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View rowView = inflater.inflate(R.layout.drivinglog_list_item, parent, false);
            TextView tv_datehours = (TextView) rowView.findViewById(R.id.tv_dateHours);
            ImageView iv_lessonType = (ImageView) rowView.findViewById(R.id.iv_lessonType);
            ImageView iv_weatherConditions = (ImageView) rowView.findViewById(R.id.iv_weatherConditions);
            String css = values[position]; //css = comma separated string
            String[] css_split = css.split(",");
            String date = css_split[0];
            String hours = css_split[1];
            String lessonType = css_split[2];
            String weatherConditions = css_split[3];
            tv_datehours.setText(String.format("%1s - %2s hours", date, hours));
            if (lessonType.equals("Residential")){
                iv_lessonType.setImageResource(R.drawable.ic_residential);
            }else if (lessonType.equals("Commercial")){
                iv_lessonType.setImageResource(R.drawable.ic_commercial);
            }else if (lessonType.equals("Highway")) {
                iv_lessonType.setImageResource(R.drawable.ic_highway);
            }
            if (weatherConditions.equals("Clear")){
                iv_weatherConditions.setImageResource(R.drawable.ic_sunny);
            }else if (weatherConditions.equals("Raining")){
                iv_weatherConditions.setImageResource(R.drawable.ic_rainy);
            }else if (weatherConditions.equals("Snow/Ice")) {
                iv_weatherConditions.setImageResource(R.drawable.ic_snowy);
            }

            return rowView;
        }
    }
 }

fragment_driving_log.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:context="DrivingLog">

    <!-- TODO: Update blank fragment layout -->

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


</LinearLayout>

drivinglog_list_item.xml

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


    <TextView
        android:text="TextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/tv_dateHours"
        android:layout_weight="1" />

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:srcCompat="@mipmap/ic_launcher"
        android:id="@+id/iv_lessonType"
        android:layout_weight="1" />

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:srcCompat="@mipmap/ic_launcher"
        android:id="@+id/iv_weatherConditions"
        android:layout_weight="0.18" />
</LinearLayout>

When I switch to the DrivingLog fragment from MainActivity, nothing shows up.

Where am I going wrong?

Answer 1

You need to call super(context, layoutId,values) because super(context, layoutId,) will generate an empty list inside adapter and the count will be zero so to represent the original count of data use the suggested constructor so use

public DrivingLogAdapter(Context context, int layoutId, String[] values)
   {
       super(context, layoutId,values);
       this.context = context;
       this.values = values;
   }

Answer 2

You are missing this

@Override
public int getCount() {
return super.getCount();
}

in DrivingLogAdapter class.

plus try super(context, layoutId,values); in DrivingLogAdapter constructor