Android: Making a dynamic listview

I'm having a JSON file which is populated to a listview.

I wanna make the list view dynamic. That means, I only need one Activity for the click action on the list I have. And the source of the content (picture,title,description) which is populated to the Activity comes from a JSON file on the web.

For example, I have 13 projects on the list, whenever I click one of them it goes to ONE activity containing different picture,title,and description depends on the item I click.

I need somebody to improve the codes I provide below.

Projects.java

public class Projects {

    public String title;
    public String keyword;
    public String description;
    public String smallImageUrl;
    public String bigImageUrl;
    public int cost;

    @Override
    public String toString()
    {
        return "Title: "+title+ " Keyword: "+keyword+ " Image: "+smallImageUrl;

    }


}

ProjectsAdapter.java

Public class ProjectsAdapter extends ArrayAdapter<Projects> {

    int resource;
    String response;
    Context context;
    //Initialize adapter
    public ProjectsAdapter(Context context, int resource, List<Projects> items) {
        super(context, resource, items);
        this.resource=resource;

    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent)
    {
        LinearLayout projectView;
        //Get the current alert object
        Projects pro = getItem(position);

        //Inflate the view
        if(convertView==null)
        {
            projectView = new LinearLayout(getContext());
            String inflater = Context.LAYOUT_INFLATER_SERVICE;
            LayoutInflater vi;
            vi = (LayoutInflater)getContext().getSystemService(inflater);
            vi.inflate(resource, projectView, true);
        }
        else
        {
            projectView = (LinearLayout) convertView;
        }

        TextView Title =(TextView)projectView.findViewById(R.id.title);

        try {
              ImageView i = (ImageView)projectView.findViewById(R.id.image);
              Bitmap bitmap = BitmapFactory.decodeStream((InputStream)new URL(pro.smallImageUrl).getContent());
              i.setImageBitmap(bitmap); 
            } catch (MalformedURLException e) {
              e.printStackTrace();
            } catch (IOException e) {
              e.printStackTrace();
            }


        //Assign the appropriate data from our alert object above
        //Image.setImageDrawable(pro.smallImageUrl);
        Title.setText(pro.title);

        return projectView;
    }

}

Main.java

public class Main extends Activity {
    /** Called when the activity is first created. */
    //ListView that will hold our items references back to main.xml
    ListView lstTest;
    //Array Adapter that will hold our ArrayList and display the items on the ListView
    ProjectsAdapter arrayAdapter;

    //List that will  host our items and allow us to modify that array adapter
    ArrayList<Projects> prjcts=null;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        //Initialize ListView
        lstTest= (ListView)findViewById(R.id.lstText);

         //Initialize our ArrayList
        prjcts = new ArrayList<Projects>();
        //Initialize our array adapter notice how it references the listitems.xml layout
        arrayAdapter = new ProjectsAdapter(Main.this, R.layout.listitems,prjcts);

        //Set the above adapter as the adapter of choice for our list
        lstTest.setAdapter(arrayAdapter);

        //Instantiate the Web Service Class with he URL of the web service not that you must pass
        WebService webService = new WebService("http://pre.spendino.de/test/android/projects.json");

        //Pass the parameters if needed , if not then pass dummy one as follows
        Map<String, String> params = new HashMap<String, String>();
        params.put("var", "");

        //Get JSON response from server the "" are where the method name would normally go if needed example
        // webService.webGet("getMoreAllerts", params);
        String response = webService.webGet("", params);

        try
        {
            //Parse Response into our object
            Type collectionType = new TypeToken<ArrayList<Projects>>(){}.getType();

            //JSON expects an list so can't use our ArrayList from the lstart
            List<Projects> lst= new Gson().fromJson(response, collectionType);

            //Now that we have that list lets add it to the ArrayList which will hold our items.
            for(Projects l : lst)
            {
                prjcts.add(l);
            }

            //Since we've modified the arrayList we now need to notify the adapter that
            //its data has changed so that it updates the UI
            arrayAdapter.notifyDataSetChanged();
        }
        catch(Exception e)
        {
            Log.d("Error: ", e.getMessage());
        }

        lstTest.setOnItemClickListener(new OnItemClickListener() {
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {              
            @SuppressWarnings("unchecked")
            Projects p = (Projects ) lstTest.getItemAtPosition(position);                   
            //Do your logic and open up a new Activity.
            Intent care = new Intent(Main.this, Organization.class);
            startActivity(care);
        }
    });

    }

}

WebService.java (I don't think we need to edit this one)

public class WebService{

    DefaultHttpClient httpClient;
    HttpContext localContext;
    private String ret;

    HttpResponse response1 = null;
    HttpPost httpPost = null;
    HttpGet httpGet = null;
    String webServiceUrl;

    //The serviceName should be the name of the Service you are going to be using.
    public WebService(String serviceName){
        HttpParams myParams = new BasicHttpParams();

        HttpConnectionParams.setConnectionTimeout(myParams, 10000);
        HttpConnectionParams.setSoTimeout(myParams, 10000);
        httpClient = new DefaultHttpClient(myParams);
        localContext = new BasicHttpContext();
        webServiceUrl = serviceName;

    }

    //Use this method to do a HttpPost\WebInvoke on a Web Service
    public String webInvoke(String methodName, Map<String, Object> params) {

        JSONObject jsonObject = new JSONObject();

        for (Map.Entry<String, Object> param : params.entrySet()){
            try {
                jsonObject.put(param.getKey(), param.getValue());
            }
            catch (JSONException e) {
                Log.e("Groshie", "JSONException : "+e);
            }
        }
        return webInvoke(methodName,  jsonObject.toString(), "application/json");
    }

    private String webInvoke(String methodName, String data, String contentType) {
        ret = null;

        httpClient.getParams().setParameter(ClientPNames.COOKIE_POLICY, CookiePolicy.RFC_2109);

        httpPost = new HttpPost(webServiceUrl + methodName);
        response1 = null;

        StringEntity tmp = null;       

        //httpPost.setHeader("User-Agent", "SET YOUR USER AGENT STRING HERE");
        httpPost.setHeader("Accept",
"text/html,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5");

        if (contentType != null) {
            httpPost.setHeader("Content-Type", contentType);
        } else {
            httpPost.setHeader("Content-Type", "application/x-www-form-urlencoded");
        }

        try {
            tmp = new StringEntity(data,"UTF-8");
        } catch (UnsupportedEncodingException e) {
            Log.e("Groshie", "HttpUtils : UnsupportedEncodingException : "+e);
        }

        httpPost.setEntity(tmp);

        Log.d("Groshie", webServiceUrl + "?" + data);

        try {
            response1 = httpClient.execute(httpPost,localContext);

            if (response1 != null) {
                ret = EntityUtils.toString(response1.getEntity());
            }
        } catch (Exception e) {
            Log.e("Groshie", "HttpUtils: " + e);
        }

        return ret;
    }

    //Use this method to do a HttpGet/WebGet on the web service
    public String webGet(String methodName, Map<String, String> params) {
        String getUrl = webServiceUrl + methodName;

        int i = 0;
        for (Map.Entry<String, String> param : params.entrySet())
        {
            if(i == 0){
                getUrl += "?";
            }
            else{
                getUrl += "&";
            }

            try {
                getUrl += param.getKey() + "=" + URLEncoder.encode(param.getValue(),"UTF-8");
            } catch (UnsupportedEncodingException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            i++;
        }

        httpGet = new HttpGet(getUrl);
        Log.e("WebGetURL: ",getUrl);

        try {
            response1 = httpClient.execute(httpGet);
        } catch (Exception e) {
            Log.e("Groshie:", e.getMessage());
        }

        // we assume that the response body contains the error message
        try {
            ret = EntityUtils.toString(response1.getEntity());
        } catch (IOException e) {
            Log.e("Groshie:", e.getMessage());
        }

        return ret;
    }

    public static JSONObject Object(Object o){
        try {
            开发者_高级运维return new JSONObject(new Gson().toJson(o));
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return null;
    }

    public InputStream getHttpStream(String urlString) throws IOException {
        InputStream in = null;
        int response = -1;

        URL url = new URL(urlString);
        URLConnection conn = url.openConnection();

        if (!(conn instanceof HttpURLConnection))
            throw new IOException("Not an HTTP connection");

        try{
            HttpURLConnection httpConn = (HttpURLConnection) conn;
            httpConn.setAllowUserInteraction(false);
            httpConn.setInstanceFollowRedirects(true);
            httpConn.setRequestMethod("GET");
            httpConn.connect();

            response = httpConn.getResponseCode();                

            if (response == HttpURLConnection.HTTP_OK) {
                in = httpConn.getInputStream();
            }
        } catch (Exception e) {
            throw new IOException("Error connecting");
        } // end try-catch

        return in;
    }

    public void clearCookies() {
        httpClient.getCookieStore().clear();
    }

    public void abort() {
        try {
            if (httpClient != null) {
                System.out.println("Abort.");
                httpPost.abort();
            }
        } catch (Exception e) {
            System.out.println("Your App Name Here" + e);
        }
    }


}

EDIT What I wanna show in Organization.java is this .xml file:

<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:background="@drawable/bg"
  android:orientation="vertical">

  <ImageView
        android:id="@+id/project_image"
        android:layout_marginTop="10dp"   
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"/>
   <TextView
        android:id="@+id/title"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="Default Title"
        android:textSize="18sp"
        android:textStyle="bold"
        android:textColor="#78b257"/>

        <LinearLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_marginTop="15dp"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:orientation="horizontal">
        <Button 
         android:id="@+id/btn_forward"
         android:layout_marginLeft="5dp"
         android:layout_gravity="left"
         android:text="Weitersagen"
         android:layout_height="wrap_content"
         android:layout_width="wrap_content"
         android:layout_marginTop="15dp"/>

         <Button 
        android:id="@+id/btn_sms_spend"
        android:layout_marginTop="15dp"
        android:layout_marginRight="5dp"
        android:text="Per SMS spenden"
        android:layout_gravity="right" 
        android:layout_height="wrap_content"
        android:layout_width="wrap_content"/>

         </LinearLayout>

         <ScrollView
            android:layout_width="fill_parent"
            android:layout_height="wrap_content">

         <LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:background="@drawable/bg_white"
  android:orientation="vertical">

   <TextView
        android:id="@+id/description"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="5dp"
        android:layout_marginLeft="5dp"
        android:gravity="left"
        android:text="default description"
        android:textSize="18sp"
        android:textColor="#000000"/>


   </LinearLayout>
   </ScrollView>

</LinearLayout>

and here's the JSON file:

[{
    "title": "CARE Deutschland-Luxemburg e.V.",
    "keyword": "CARE",
    "description": "<p><b>Das CARE-Komplett-Paket für Menschen in Not</b",
    "smallImageUrl": "http://cdn.spendino.de/web/img/projects/home/1284113658.jpg",
    "bigImageUrl":"http://cdn.spendino.de/web/img/projects/small/1284113658.jpg",
    "cost": "5"
},
{
    "title": "Brot für die Welt",
    "keyword": "BROT",
    "description": "<p>„Brot für die Welt“ unterstützt unter der Maßgabe 'Helfen, wo die Not am größten ist' ausgewählte Projekte weltweit.",
    "smallImageUrl": "http://cdn.spendino.de/web/img/projects/home/1267454286.jpg",
    "bigImageUrl":"http://cdn.spendino.de/web/img/projects/small/1267454286.jpg",
    "cost": "5"
},
{
    "title": "Deutsche AIDS-Stiftung",
    "keyword": "HIV",
    "description": "<p>Die Deutsche AIDS-Stiftung unterstützt mit ihren finanziellen Mitteln seit mehr als 20 Jahren Betroffene, die an HIV und AIDS erkrankt sind.",
    "smallImageUrl": "http://cdn.spendino.de/web/img/projects/home/1258365722.jpg",
    "bigImageUrl":"http://cdn.spendino.de/web/img/projects/small/1258365722.jpg",
    "cost": "5"
}]

Screenshot of the list view:

If these are the steps I gotta do, then I'm having trouble with number 4 & 5: 1. Have the JSON 2. construct a suitable data structure (an Array, ArrayList, whatever you like) to hold crucial data about your list view 3. Use this data structure as the source for your list view 4. when the user clicks on any row, try to find out the position of the row in the list view, and on that position in your source data structure, look for the data needed. 5. create any activity which handles these data generally 6. open that activity with the data of the row which user clicked in step 4 7. Consume this data in your new activity

ConstantData.java:

public class ConstantData extends ArrayList<Projects>{


    private static final long serialVersionUID = 9100099012485622682L;
    public static Object projectsList;

    public ConstantData(){

    }

    public ConstantData(Parcel in){

    }

    @SuppressWarnings("unchecked")

    public static final Parcelable.Creator CREATOR = new Parcelable.Creator(){
        public ConstantData createFromParcel (Parcel in){
            return new ConstantData(in);
        }

        public Object[] newArray(int arg0){
            return null;
        }


    };

    private void readFromParcel(Parcel in){
        this.clear();

        int size = in.readInt();

        for (int i = 0; i < size; i++){
            Projects p = new Projects();
            p.setTitle(in.readString());
            p.setKeyword(in.readString());
            p.setSmallImageUrl(in.readString());
            p.setBigImageUrl(in.readString());
            p.setCost(in.readInt());
        }

    }


    public int describeContents() {
        return 0;
    }

    public void writeToParcel (Parcel dest, int flags){

        int size = this.size();

        dest.writeInt(size);

        for (int i = 0; i < size; i++){
            Projects p = this.get(i);
            dest.writeString(p.getTitle());
            dest.writeString(p.getKeyword());
            dest.writeString(p.getDescription());
            dest.writeString(p.getSmallImageUrl());
            dest.writeString(p.getBigImageUrl());
            dest.writeInt(p.getCost());
        }
    }


}

If something is not clear, please let me know. Thank you very much

For that you need A data structure that holds all your json nodes on index and it should be accessible for all the activities you need [Reco: Use something like GlobalVariables or ConstantData where you have all your project properties and make it public static].

Like : ConstantData.projectData which may be the arraylist or array that contains only Project objects

1. Now from list view onItemClick method you will get an index (position that denotes on which row its clicked), pass this on your single designed activity with help of bundles and extras.

2.Fetch the index in your desired activity. Fetch the project object on that index from ConstantData.projectData.

Populate the UI components from your project object.

By doing this you can inflate same view again and again only passing the index, only populating the list can be a heavy operation, but the rest will be quicker....

Edit: Let me provide you the snippets .

for 1. on Main.java you use these line in itemClick methods

Intent care = new Intent(Main.this, Organization.class);
            startActivity(care);

Add this line between startActivity and Intent initialization.

care.putExtra("yourPackageStructure.Organization.position",position);

for 2. In Organization.java 2.1 create an integer member called mPosition[or the name you like] 2.2 in onCreate() method write mPosition = getIntent().getExtras().getInt("yourPackageStructure.Organization.position");

Project project = ConstantData.projectsData.get(mPosition);

As I don't know how what is there in Organization.java and I wanted to say an array list or something that holds your Projects objects.

Here is what you can have Organization.java 's onCreate method.

onCreate(){
position = getIntent().getExtras().getInt("yourPackageStructure.Organization.position");

//Below line will get you the projects object
Projects project = ConstantData.projectsList.itemAt(position);

ImageView projectImage = (ImageView)findViewById(R.id.project_image);

Bitmap image = getImageFromUrl(this,project.bigImageUrl);

projectImage.setBitmapDrawable(image);

TextView title = (TextView)findViewById(R.id.title);

title.setText(project.title);

TextView description = (TextView)findViewById(R.id.description);

description .setText(project.description);

}

This is what i use for getImageFromUrl method

public static Bitmap getImageFromUrl(Context context, String urlString) {
        try {
            if (haveInternet(context)) {
                URL url = new URL(urlString);
                HttpURLConnection conn = (HttpURLConnection) url
                        .openConnection();
                conn.setDoInput(true);
                conn.connect();
                int length = conn.getContentLength();
                InputStream is = conn.getInputStream();
                Bitmap bmImg = BitmapFactory.decodeStream(is);
                return bmImg;
            } else {

                return null;
            }
        } catch (MalformedURLException e) {
            Log.e("Problem in image", e.toString(), e);
            e.printStackTrace();
        } catch (Exception e) {
            Log.e("Problem in image", e.toString(), e);
        }
        return null;
    }

This is the haveInternet Method

private static boolean haveInternet(Context context) {
        NetworkInfo info = getNetworkInfo(context);
        if (info == null || !info.isConnected()) {
            return false;
        }
        if (info.isRoaming()) {
            // here is the roaming option you can change it if you want to
            // disable internet while roaming, just return false
            return true;
        }
        return true;
    }

Hoping it helps you properly...

Added ConstantData

ConstantData.java

public class ConstantData{

//All public static members will be here 

public static final long guid = A LONG VAL;

public static String licenceText = A STRING VAL;

//etc... etc... above members are just the idea that what kind of members can be there in //ConstantData... I normally use all public static properties here

//Here is the variable you probably want

public static ArrayList<Projects> projectsList = new ArrayList<Projets>();
}

if you want to populate this array list you can do it from main.java check the lines

for(Projects l : lst)
{
      prjcts.add(l);
}

You can add or replace this line. ConstantData.projectsList.add(l); I recommend you to add the line rather to display the line.....