Alternate row Colors in ListView

Question

I am writing an Android App using Android Studio that uses XMLPullParser to read an xml file from file. After it i want to have an alternate row Colors in my ListView,i see this topic and add @Override getView method to my adapter,but it does not work for me,,,what is my problem?

MainActivity.java

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

import android.os.Bundle;
import android.view.Menu;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.app.Activity;
public class MainActivity extends Activity {

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

    ListView listView = (ListView) findViewById(R.id.listView1);

    List<App> apps = null;
    try {
        XMLPullParserHandler parser = new XMLPullParserHandler(getApplicationContext());
        InputStream is=getAssets().open("apps.xml");
        apps = parser.parse(is);

        ArrayAdapter<App> adapter =new ArrayAdapter<App>
                (this,android.R.layout.simple_list_item_1, apps);
        listView.setAdapter(adapter);

    } catch (IOException e) {e.printStackTrace();}

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;


   }

}

App.java

import android.content.Context;
import android.graphics.Color;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;

import java.util.ArrayList;

/**
 * Created by ali on 07/29/2016.
 */
public class App extends ArrayAdapter{

private int id,location;
private String title,activity,address;

public App(Context context, int resource) {
    super(context, resource);
}


public int getId() {
    return id;
}
public void setId(int id) {
    this.id = id;
}
public String getTitle() {
    return title;
}
public void setTitle(String title) {
    this.title = title;
}
public String getActivity() {
    return activity;
}
public void setActivity(String activity) {
    this.activity = activity;
}
public int getLocation(){
    return location;
}
public void setLocation(int location)
{
    this.location=location;
}
public String getAddress(){
    return address;
}
public void setAddress(String address)
{
    this.address=address;
}

@Override
public String toString() {
    return id + "\n " + title + "\n" +activtiy+"\n"+location+"\n"+address;

}
   @Override
    public View getView(int position,View convertView, ViewGroup parent)
    {
        View view = super.getView(position, convertView, parent);
        if (position % 2 == 1) {
            view.setBackgroundColor(Color.BLUE);
        } else {
            view.setBackgroundColor(Color.CYAN);
        }

    return view;
}


}

XMLPullParserHandler.java

    import android.app.Activity;
import android.content.Context;
import android.content.res.Resources;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlPullParserFactory;

public class XMLPullParserHandler{

Context context;

public XMLPullParserHandler(Context context) {
    this.context = context;
}

private List<App> apps= new ArrayList<App>();
private App app;
private String text;


public List<App> getApps() {
    return apps;
}

public List<App> parse(InputStream is) {

    try {
        XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
        factory.setNamespaceAware(true);
        XmlPullParser  parser = factory.newPullParser();

        parser.setInput(is, null);

        int eventType = parser.getEventType();
        while (eventType != XmlPullParser.END_DOCUMENT) {
            String tagname = parser.getName();
            switch (eventType) {
                case XmlPullParser.START_TAG:
                    if (tagname.equalsIgnoreCase("app")) {
                        app = new App(context,android.R.layout.simple_list_item_1);
                    }
                    break;

                case XmlPullParser.TEXT:
                    text = parser.getText();
                    break;

                case XmlPullParser.END_TAG:
                    if (tagname.equalsIgnoreCase("app")) {
                        apps.add(app);
                    }else if (tagname.equalsIgnoreCase("id")) {
                        app.setId(Integer.parseInt(text));
                    }  else if (tagname.equalsIgnoreCase("title")) {
                        app.setTitle(text);
                    } else if (tagname.equalsIgnoreCase("activity")) {
                        app.setActivity(text);
                    } else if (tagname.equalsIgnoreCase("location")){
                        app.setLocation(Integer.parseInt(text));
                    } else if (tagname.equalsIgnoreCase("address")){
                        app.setAddress(text);
                    }

                    break;

                default:
                    break;
            }
            eventType = parser.next();
        }

    } catch (XmlPullParserException e) {e.printStackTrace();}
    catch (IOException e) {e.printStackTrace();}

    return apps;
    }
}

activity_main.xml

<RelativeLayout 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" >

<ListView
    android:id="@+id/listView1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:divider="#d8d8d8"
    android:dividerHeight="1dp">

</ListView>

Answer 1

Here what you need to do create a CustomAdapter:

public class CustomAdapter extends ArrayAdapter<App> {

    public CustomAdapter (Context context) {
        super(context);
    }

    public View getView(int position, View view, ViewGroup root) {
        CustomHolder holder;
        if(view == null) {
            view = LayoutInflater.from(this.getContext()).inflate(R.layout.simple_list_item_1, root, false);
            holder = new CustomHolder();
            view.setBackgroundColor(position % 2 ==  ? Color 1 : Color 2);
            view.setTag(holder);
        } else {
            holder = (CustomHolder)view.getTag();
        }

        holder.setApp((App)this.getItem(position));
        return view;
    }

    public static class CustomHolder{
        public void setApp(App app){//DO YOUR THING}

        public CustomHolder () {
        }
    }
}

Then your activity should look like this:

import android.os.Bundle;
import android.view.Menu;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.app.Activity;
public class MainActivity extends Activity {

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

    ListView listView = (ListView) findViewById(R.id.listView1);

    List<App> apps = null;
    try {
        XMLPullParserHandler parser = new XMLPullParserHandler(getApplicationContext());
        InputStream is=getAssets().open("apps.xml");
        apps = parser.parse(is);

        CustomAdapter<App> adapter = new CustomAdapter (this);
        listView.setAdapter(adapter);

    } catch (IOException e) {e.printStackTrace();}

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;  
   }    
}