How To Use List Adapter

Question

My app displays information from a database in a ListView.

In the ListView, there is also a VideoView which is supposed to load and play a video from my website.

In a separate app with only this function, I got it to work. The difference is that in the working app the videoview is located IN the activity_main.xml file, whereas in my new app, the videoview is located in a separate list_item.xml file which is loaded into activity_main.xml as a ListView.

I was told by another stack overflow user that because the VideoView is not in activity_main.xml, I'd have to create a ListAdapter and have the getView() method of the list adapter reference my list_item.xml layout file.

I found a tutorial on ListAdapters but it seemed that the context was too different from what I'm trying to achieve for me to be able to adapt it to my use.

Can someone help me understand how I might go about implementing a ListAdapter that would work with my current code?

Thanks in advance, I really appreciate the help.

BELOW ARE MY FILES

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<!-- Main ListView 
     Always give id value as list(@android:id/list)
-->
<ListView
    android:id="@android:id/list"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"/>

</LinearLayout>

list_item.xml:

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

<!-- Name Label -->
<TextView
    android:id="@+id/name"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:paddingTop="6dip"
    android:paddingLeft="6dip"
    android:textSize="17dip"
    android:textStyle="bold" />

    <VideoView
     android:id="@+id/videoView"
     android:layout_width="100dp"
     android:layout_height="100dp"
     />

            <ImageButton
    android:id="@+id/imageButton2"
    android:layout_width="60dp"
    android:layout_height="60dp"
    android:src="@drawable/ic_videobutton"
    android:onClick="sendMessage" />

</LinearLayout>

AllProductsActivity.java:

package com.example.androidhive;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.apache.http.NameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.MediaController;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.VideoView;

public class AllProductsActivity extends ListActivity {

// Progress Dialog
private ProgressDialog pDialog;

// Creating JSON Parser object
JSONParser jParser = new JSONParser();

ArrayList<HashMap<String, String>> productsList;

// get video url
private static final String MOVIE_URL ="http://mywebsite.com/mycameraapp/android_connect/videos/testvideo.mkv";

// url to get all products list
private static String url_all_products = "http://mywebsite.com/mycameraapp/android_connect/get_all_products.php";

// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_PRODUCTS = "products";
private static final String TAG_PID = "pid";
private static final String TAG_NAME = "name";
private static final String TAG_DESCRIPTION = "description";

// products JSONArray
JSONArray products = null;

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



    // **MY VIDEOVIEW CODE THAT DOESN'T WORK BECAUSE THIS VIDEOVIEW IS IN list_item.xml**
    VideoView vid = (VideoView) findViewById(R.id.videoView);
    Uri video = Uri.parse(MOVIE_URL);
    vid.setMediaController(new MediaController(this));
    vid.setVideoURI(video);
    vid.start();
    vid.requestFocus();



    // Hashmap for ListView
    productsList = new ArrayList<HashMap<String, String>>();

    // Loading products in Background Thread
    new LoadAllProducts().execute();

    // Get listview
    ListView lv = getListView();

    // on seleting single product
    // launching Edit Product Screen
    lv.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
            // getting values from selected ListItem
            String pid = ((TextView) view.findViewById(R.id.pid)).getText()
                    .toString();

            // Starting new intent
            Intent in = new Intent(getApplicationContext(),
                    EditProductActivity.class);
            // sending pid to next activity
            in.putExtra(TAG_PID, pid);

            // starting new activity and expecting some response back
            startActivityForResult(in, 100);
        }
    });


}

/** CALLED WHEN THE USER CLICKS THE RECORD BUTTON */
public void sendMessage(View view) {
    Intent videoIntent = new Intent(this, PhotoIntentActivity.class);
    startActivity(videoIntent);
}

// Response from Edit Product Activity
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    // if result code 100
    if (resultCode == 100) {
        // if result code 100 is received 
        // means user edited/deleted product
        // reload this screen again
        Intent intent = getIntent();
        finish();
        startActivity(intent);
    }

}

/**
 * Background Async Task to Load all product by making HTTP Request
 * */
class LoadAllProducts extends AsyncTask<String, String, String> {

    /**
     * Before starting background thread Show Progress Dialog
     * */
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(AllProductsActivity.this);
        pDialog.setMessage("Loading products. Please wait...");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(false);
        pDialog.show();
    }

    /**
     * getting All products from url
     * */
    protected String doInBackground(String... args) {
        // Building Parameters
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        // getting JSON string from URL
        JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);

        // Check your log cat for JSON reponse
        Log.d("All Products: ", json.toString());

        try {
            // Checking for SUCCESS TAG
            int success = json.getInt(TAG_SUCCESS);

            if (success == 1) {
                // products found
                // Getting Array of Products
                products = json.getJSONArray(TAG_PRODUCTS);

                // looping through All Products
                for (int i = 0; i < products.length(); i++) {
                    JSONObject c = products.getJSONObject(i);

                    // Storing each json item in variable
                    String id = c.getString(TAG_PID);
                    String name = c.getString(TAG_NAME);
                    String description = c.getString(TAG_DESCRIPTION);

                    // creating new HashMap
                    HashMap<String, String> map = new HashMap<String, String>();

                    // adding each child node to HashMap key => value
                    map.put(TAG_PID, id);
                    map.put(TAG_NAME, name);
                    map.put(TAG_DESCRIPTION, description);

                    // adding HashList to ArrayList
                    productsList.add(map);
                }
            } else {
                // no products found
                // Launch Add New product Activity
                Intent i = new Intent(getApplicationContext(),
                        NewProductActivity.class);
                // Closing all previous activities
                i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                startActivity(i);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }

        return null;
    }

    /**
     * After completing background task Dismiss the progress dialog
     * **/
    protected void onPostExecute(String file_url) {
        // dismiss the dialog after getting all products
        pDialog.dismiss();
        // updating UI from Background Thread
        runOnUiThread(new Runnable() {
            public void run() {
                /**
                 * Updating parsed JSON data into ListView
                 * */
                ListAdapter adapter = new SimpleAdapter(
                        AllProductsActivity.this, productsList,
                        R.layout.list_item, new String[] { TAG_PID, TAG_NAME, TAG_DESCRIPTION},
                        new int[] { R.id.pid, R.id.name, R.id.description });
                // updating listview
                setListAdapter(adapter);

            }


        });

    }

}

}

Answer 1

An adapter is used to tie the data to the ListView. You should probably create a new class to represent each item in the ListView instead of using an List of HashMaps.

public class MyAdapter extends ArrayAdapter<MyItem>
{
    private final List<MyItem>     mItems;
    private final Context          mContext;
    private final LayoutInflater   mInflater;

    public MyAdapter (Context context, int resourceId, ArrayList<MyItem> items)
    {
        super(context, resourceId, rescues);

        mContext = context;
        mItems = items;
        inflater = (LayoutInflater)mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent)
    {
        ViewHolder holder;
        if (convertView == null)
        {
            convertView = inflater.inflate(R.layout.list_item, null);
            holder = new ViewHolder();
            holder.name = (TextView)convertView.findViewById(R.id.name);
            holder.video = (VideoView)convertView.findViewById(R.id.videoView);
            holder.button = (ImageButton)convertView.findViewById(R.id.imageButton2);
            convertView.setTag(holder);
        }
        else
        {
            holder = (ViewHolder)convertView.getTag();
        }

        MyItem item = getItem(position);
        if (item != null)
        {
            // This is where you set up the views.
            // This is just an example of what you could do.
            holder.text.setText(item.getName());
            holder.video.setMediaController(new MediaController(mContext));
            holder.button.setImageDrawable(item.getImageDrawable());
            holder.button.setOnClickListener(
                new View.OnClickListener()
                {
                    @Override
                    public void onClick(View view)
                    {
                        holder.video.setVideoURI(item.getURI());
                        holder.video.start();
                    }
                }
            );
        }

        return convertView;
    }

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

    @Override
    public MyItem getItem(int position)
    {
        return mItems.get(position);
    }

    public class ViewHolder
    {
        TextView    text;
        VideoView   video;
        ImageButton button;
    }
}

In your AllProductsActivity class:

/**
 * After completing background task Dismiss the progress dialog
 * **/
protected void onPostExecute(String file_url) {
    // dismiss the dialog after getting all products
    pDialog.dismiss();
    // updating UI from Background Thread
    runOnUiThread(new Runnable() {
        public void run() {
            /**
             * Updating parsed JSON data into ListView
             * */
            MyAdapter adapter = new MyAdapter(AllProductsActivity.this,
                R.layout.list_item, productsList);

            // updating listview
            setListAdapter(adapter);

        }