Android Open Source - CSVListExample C S V Adapter

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License

The source code is released under:

Apache License

Java Source Code

package com.makemyandroidapp.example.csvlist;
/* ww w. j  a v  a 2 s. c o m*/
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

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


/*
 * Very basic Custom Adapter that takes state name,capital pairs out of a csv
 * file from the assets and uses those values to build a List of State objects.
 * Overrides the default getView() method to return a TextView with the state name.
 * 
 * ArrayAdapter - a type of Adapter that works a lot like ArrayList.
 */
public class CSVAdapter extends ArrayAdapter<State>{
  Context ctx;
  
  //We must accept the textViewResourceId parameter, but it will be unused
  //for the purposes of this example.
  public CSVAdapter(Context context, int textViewResourceId) {
    super(context, textViewResourceId);
    
    //Store a reference to the Context so we can use it to load a file from Assets.
    this.ctx = context;
    
    //Load the data.
    loadArrayFromFile();  
  }
  
  
  
  /*
   * getView() is the method responsible for building a View out of a some data that represents
   * one row within the ListView. For this example our row will be a single TextView that
   * gets populated with the state name.
   * (non-Javadoc)
   * @see android.widget.ArrayAdapter#getView(int, android.view.View, android.view.ViewGroup)
   */
  @Override
  public View getView(final int pos, View convertView, final ViewGroup parent){
    /*
     * Using convertView is important. The system will pass back Views that have been
     * created but scrolled off of the top (or bottom) of the screen, and thus are no
     * longer being shown on the screen. Since they are unused, we can "recycle" them
     * instead of creating a new View object for every row, which would be wasteful, 
     * and lead to poor performance. The diference may not be noticeable in this
     * small example. But with larger more complex projects it will make a significant
     * improvement by recycling Views rather than creating new ones for each row.
     */
    TextView mView = (TextView)convertView;
    //If convertView was null then we have to create a new TextView.
    //If it was not null then we'll re-use it by setting the appropriate
    //text String to it.
    if(null == mView){ 
      mView = new TextView(parent.getContext());
      mView.setTextSize(28);
    }
    
    //Set the state name as the text.
    mView.setText(getItem(pos).getName());
    
    //We could handle the row clicks from here. But instead
    //we'll use the ListView.OnItemClickListener from inside
    //of MainActivity, which provides some benefits over doing it here.
    
    /*mView.setOnClickListener(new OnClickListener(){
      public void onClick(View v){
        Toast.makeText(parent.getContext(), getItem(pos).getCapital(), Toast.LENGTH_SHORT).show();
      }
    });*/
    
    return mView;
  }
  
  /*
   * Helper method that loads the data from the states.csv and builds
   * each csv row into a State object which then gets added to the Adapter.
   */
  private void loadArrayFromFile(){
    try {
      // Get input stream and Buffered Reader for our data file.
      InputStream is = ctx.getAssets().open("states.csv"); 
      BufferedReader reader = new BufferedReader(new InputStreamReader(is));
      String line;
      
      //Read each line
      while ((line = reader.readLine()) != null) {
        
        //Split to separate the name from the capital
        String[] RowData = line.split(",");
        
        //Create a State object for this row's data.
        State cur = new State();
        cur.setName(RowData[0]);
        cur.setCapital(RowData[1]);
        
        //Add the State object to the ArrayList (in this case we are the ArrayList).
        this.add(cur);
      }
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
  

}

Java Source Code List

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