Question

As my post states, I can’t seem to get my ArrayAdapter to update the whole list despite the call "adapter.notifyDataSetChanged();" Only the last element in the list is updated.

Can someone maby see what I’m doing wrong below??

Here is my custom adapter

import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

public class WeatherAdapter extends ArrayAdapter<Weather>{

    Context context; 
    int layoutResourceId;    
    Weather data[] = null;
    private WeatherHolder holder;
    private Weather weather;


    public WeatherAdapter(Context context, int layoutResourceId, Weather[] data) {
        super(context, layoutResourceId, data);
        this.layoutResourceId = layoutResourceId;
        this.context = context;
        this.data = data;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View row = convertView;
        holder = null;

        if(row == null)
        {
            LayoutInflater inflater = ((Activity)context).getLayoutInflater();
            row = inflater.inflate(layoutResourceId, parent, false);

            holder = new WeatherHolder();
            holder.imgIcon = (TextView)row.findViewById(R.id.imgen);
            holder.txtTitle = (TextView)row.findViewById(R.id.txtTitle);

            row.setTag(holder);
        }
        else
        {
            holder = (WeatherHolder)row.getTag();
        }

        weather = data[position];
        holder.txtTitle.setText(weather.getName());
        //holder.imgIcon.setText(Double.toString(weather.getBuyingRate()));
        return row;
    }

    public void update(String buttonPressed){
        if(buttonPressed == "Köp Kurs"){
                            holder.imgIcon.setText(Double.toString(weather.getBuyingRate()));//This updates only the last element in list but I want to update every element in the list



        }
        else if(buttonPressed == "Antal"){              holder.imgIcon.setText(Double.toString(weather.getNrOfSharesInPortfolio()));//This updates only the last element in list but I want to update every element in the list


        }
    }

    static class WeatherHolder
    {
        TextView imgIcon;
        TextView txtTitle;
    }
}

And here is my main class, when I call “Update()” method only the last element in the list is updated but not the others. How can I update the whole list instead of just the last element in the list?

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ListView;

public class MainActivity extends Activity {

    private ListView listView1;
    private Button goButton;
    private String[] listheader = {"Köp Kurs","Antal"};
    private WeatherAdapter adapter;
    private int totalElemInlist = listheader.length;
    private int currentelemInList=0;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Weather weather_data[] = new Weather[]
        {
            new Weather("ABB", 56.0, 300),
            new Weather("Volvo", 89.0,500),
            new Weather("Astra Zeneca", 98.55, 50)
        };

        adapter = new WeatherAdapter(this, 
                R.layout.listview_item_row, weather_data);


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

        View header = (View)getLayoutInflater().inflate(R.layout.listview_header_row, null);
        listView1.addHeaderView(header);
        goButton = (Button) findViewById(R.id.testButton);
        goButton.setText(listheader[currentelemInList]);

        listView1.setAdapter(adapter);


        goButton.setOnClickListener(new OnClickListener() {
            public void onClick(View view) {
                String buttonPressed = (String) ((Button) view).getText();

                goThroughList(buttonPressed);
                System.out.println("Button Clicked" + buttonPressed);
            }
          });
    }

    private void goThroughList(String buttonPressed){
        currentelemInList++;
        if(currentelemInList>=totalElemInlist){
            currentelemInList=0;
        }
        goButton.setText(listheader[currentelemInList]);

        if(buttonPressed == "Köp Kurs"){
            System.out.println("Köp kurs");
            adapter.update(buttonPressed);
            adapter.notifyDataSetChanged();//This only updates the last element in list
        }
        else if(buttonPressed == "Antal"){
            System.out.println("Antal");
            adapter.update(buttonPressed);
            adapter.notifyDataSetChanged();//This only updates the last element in list
        }
        System.out.println(currentelemInList);
    }
}

Answer 1

How can I update the whole list instead of just the last element in the list?

You must make your changes happen in getView(). getView() redraws every row as they appear whenever the user scrolls the ListView or notifyDataSetChanged() is called. So the changes must happen in there otherwise they will be erased.

First create a new field variable in your adapter:

private String currentImage;

Second change update() to control the contents on imgIcon:

public void update(String buttonPressed){
    currentImage = buttonPressed;
    notifyDataSetChanged();
}

Last change getView() to display the current images for each row:

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ...

    weather = data[position];
    holder.txtTitle.setText(weather.getName());

    if(currentImage.equals("Köp Kurs")){
        holder.imgIcon.setText(Double.toString(weather.getBuyingRate()));
    }
    else if(currentImage.equals("Antal")){
        holder.imgIcon.setText(Double.toString(weather.getNrOfSharesInPortfolio()));
    }
    return row;
}

(You can also simplify goThroughList(), since the if-else contains the exact same code.)