Develop Reference

How to change ListView to RecyclerView in Android Studio?

I don't know how to use RecyclerView to replace ListView. Anyone can help me? Thank you. I find out so many resources in the different online platform but I don't know how to change my code. When I trying to alter my code, it doesn't work.
Code is in the following:
MainActivity.java
public class MainActivity extends AppCompatActivity {
private String TAG = MainActivity.class.getSimpleName();
private ProgressDialog pDialog;
private ListView lv;
// URL to get contacts JSON
private static String url = "https://api.androidhive.info/contacts/";
ArrayList<HashMap<String, String>> contactList;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
contactList = new ArrayList<>();
lv = (ListView) findViewById(R.id.list);
new GetContacts().execute();
}
/**
* Async task class to get json by making HTTP call
*/
private class GetContacts extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
#Override
protected Void doInBackground(Void... arg0) {
HttpHandler sh = new HttpHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url);
Log.e(TAG, "Response from url: " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
JSONArray contacts = jsonObj.getJSONArray("contacts");
// looping through All Contacts
for (int i = 0; i < contacts.length(); i++) {
JSONObject c = contacts.getJSONObject(i);
String id = c.getString("id");
String name = c.getString("name");
String email = c.getString("email");
String address = c.getString("address");
String gender = c.getString("gender");
// Phone node is JSON Object
JSONObject phone = c.getJSONObject("phone");
String mobile = phone.getString("mobile");
String home = phone.getString("home");
String office = phone.getString("office");
// tmp hash map for single contact
HashMap<String, String> contact = new HashMap<>();
// adding each child node to HashMap key => value
contact.put("id", id);
contact.put("name", name);
contact.put("email", email);
contact.put("mobile", mobile);
// adding contact to contact list
contactList.add(contact);
}
} catch (final JSONException e) {
Log.e(TAG, "Json parsing error: " + e.getMessage());
runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(getApplicationContext(),
"Json parsing error: " + e.getMessage(),
Toast.LENGTH_LONG)
.show();
}
});
}
} else {
Log.e(TAG, "Couldn't get json from server.");
runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(getApplicationContext(),
"Couldn't get json from server. Check LogCat for possible errors!",
Toast.LENGTH_LONG)
.show();
}
});
}
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
ListAdapter adapter = new SimpleAdapter(
MainActivity.this, contactList,
R.layout.list_item, new String[]{"name", "email",
"mobile"}, new int[]{R.id.name,
R.id.email, R.id.mobile});
lv.setAdapter(adapter);
}
}
}
HttpHandler.java
public class HttpHandler {
private static final String TAG = HttpHandler.class.getSimpleName();
public HttpHandler() {
}
public String makeServiceCall(String reqUrl) {
String response = null;
try {
URL url = new URL(reqUrl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
// read the response
InputStream in = new BufferedInputStream(conn.getInputStream());
response = convertStreamToString(in);
} catch (MalformedURLException e) {
Log.e(TAG, "MalformedURLException: " + e.getMessage());
} catch (ProtocolException e) {
Log.e(TAG, "ProtocolException: " + e.getMessage());
} catch (IOException e) {
Log.e(TAG, "IOException: " + e.getMessage());
} catch (Exception e) {
Log.e(TAG, "Exception: " + e.getMessage());
}
return response;
}
private String convertStreamToString(InputStream is) {
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line;
try {
while ((line = reader.readLine()) != null) {
sb.append(line).append('\n');
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return sb.toString();
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="hk.edu.ouhk.android.jsonparsing.MainActivity">
<ListView
android:id="#+id/list"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
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"
android:padding="16dip">
<TextView
android:id="#+id/name"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingBottom="2dip"
android:paddingTop="6dip"
android:textColor="#color/colorPrimaryDark"
android:textSize="16sp"
android:textStyle="bold" />
<TextView
android:id="#+id/email"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingBottom="2dip"
android:textColor="#5d5d5d" />
<TextView
android:id="#+id/mobile"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#686868"
android:textStyle="bold" />
</LinearLayout>

as you seems to have no problem getting data from url and you successfully have made an Arraylist from the data
steps to follow now
1. add recyclerview to xml of your activity
2. make a layout how you want to display data in recyclerview items
3. then you need to make an adapter that takes data you provide and binds it to
recycler view
4. then add adapter to your recycler view
I am attaching simple recycler view which I made a while ago for me. It is simple and self explanatory. Otherwise you can comment I will explain it more
Main Activity
public class MainActivity extends AppCompatActivity {
ArrayList<String> moviesList;
RecyclerView recyclerView;
RecyclerAdapter recyclerAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
moviesList=new ArrayList<>();
recyclerView=findViewById(R.id.recyclerView);
recyclerAdapter=new RecyclerAdapter(moviesList);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setAdapter(recyclerAdapter);
moviesList.add("Kapil");
moviesList.add("Kapil");
moviesList.add("Kapil");
moviesList.add("Kapil");
moviesList.add("Kapil");
moviesList.add("Kapil");
moviesList.add("Kapil"); }
}
RecyclerAdapter in this we are creating custom viewholder for us
public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.ViewHolder>
{
public RecyclerAdapter(ArrayList<String> moviesList) {
this.moviesList = moviesList;
}
ArrayList<String> moviesList;
#NonNull
#Override
public ViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
LayoutInflater layoutInflater=LayoutInflater.from(parent.getContext());
View view=layoutInflater.inflate(R.layout.row_layout,parent,false);
ViewHolder viewHolder= new ViewHolder(view);
return viewHolder;
}
#Override
public void onBindViewHolder(#NonNull ViewHolder holder, int position) {
holder.rowTextView.setText(String.valueOf(position));
holder.textView.setText(moviesList.get(position));
}
#Override
public int getItemCount() {
return moviesList.size();
}
class ViewHolder extends RecyclerView.ViewHolder {
ImageView imageView;
TextView textView,rowTextView;
public ViewHolder(#NonNull View itemView) {
super(itemView);
imageView=itemView.findViewById(R.id.imageView);
textView=itemView.findViewById(R.id.textView);
rowTextView=itemView.findViewById(R.id.rowTextView);
}
}
}
This is layout for the item which I want to show in recycler view
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:id="#+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="22dp"
android:layout_marginTop="16dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:srcCompat="#drawable/ic_launcher_background" />
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="32dp"
android:layout_marginTop="22dp"
android:text="TextView"
android:textAppearance="#style/TextAppearance.AppCompat.Large"
app:layout_constraintStart_toEndOf="#+id/imageView"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/rowTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="33dp"
android:layout_marginTop="16dp"
android:text="TextView"
app:layout_constraintStart_toEndOf="#+id/imageView"
app:layout_constraintTop_toBottomOf="#+id/textView" />
</androidx.constraintlayout.widget.ConstraintLayout>
Just pass your array list to it. Like i did

Basically you need to create RecyclerViewAdapter with ViewHolder pattern, and just simply replace ListView to RecyclerView

ImageView Glitching AsyncTask

Im pulling images from the server with asyncTask and drawing them on imageViews. The problem is that Images sometimes get "shuffled" and it takes them couple of seconds to deploy proper image. And it can get laggy too. Is there any easier way to do that? Am I doing something wrong?
class JSONAsyncTask extends AsyncTask<String, Void, Boolean> {
ProgressDialog dialog;
#Override
protected void onPreExecute() {
super.onPreExecute();
dialog = new ProgressDialog(RecipeActivity.this);
dialog.setMessage("Loading, please wait");
dialog.setTitle("Connecting to server");
dialog.show();
dialog.setCancelable(false);
}
#Override
protected Boolean doInBackground(String... urls) {
try {
//------------------>>
HttpGet httppost = new HttpGet(urls[0]);
HttpClient httpclient = new DefaultHttpClient();
HttpResponse response = httpclient.execute(httppost);
// StatusLine stat = response.getStatusLine();
int status = response.getStatusLine().getStatusCode();
if (status == 200) {
HttpEntity entity = response.getEntity();
String data = EntityUtils.toString(entity);
//JSONObject jsono = new JSONObject(data);
//JSONArray array = jsono.getJSONArray("recepies");
JSONArray array = new JSONArray(data);
for (int i = 0; i < array.length(); i++) {
JSONObject object = array.getJSONObject(i);
Recepies rec = new Recepies();
rec.setName(object.getString("name"));
rec.setPciture(object.getString("picture"));
receptis.add(rec);
}
return true;
}
//------------------>>
} catch (ParseException e1) {
e1.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
return false;
}
protected void onPostExecute(Boolean result) {
dialog.cancel();
adapter.notifyDataSetChanged();
if (result == false)
Toast.makeText(getApplicationContext(), "Unable to fetch data from server", Toast.LENGTH_LONG).show();
}
}
and this is the MainActivity:
ArrayList<Recepies> recepies;
String nameRecepie, ingredients, priprema, picture;
Toolbar toolbar;
RecipesAdapter adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.recipes_activity);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
setTitle("Dog recepies");
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
receptis = new ArrayList<Recepti>();
new JSONAsyncTask().execute("url");
ListView listview = (ListView) findViewById(R.id.list);
adapter = new RecipesAdapter(getApplicationContext(), R.layout.row, receptis);
listview.setAdapter(adapter); //onclick listener ->
and my Adapter class
public class RecipesAdapter extends ArrayAdapter<Recepti> {
ArrayList<Recepti> receptisList;
LayoutInflater vi;
int Resource;
ViewHolder holder;
public RecipesAdapter(Context context, int resource, ArrayList<Recepti> objects) {
super(context, resource, objects);
vi = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
Resource = resource;
receptisList = objects;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
// convert view = design
View v = convertView;
if (v == null) {
holder = new ViewHolder();
v = vi.inflate(Resource, null);
holder.imageview = (ImageView) v.findViewById(R.id.ivImage);
holder.tvName = (TextView) v.findViewById(R.id.tvName);
v.setTag(holder);
} else {
holder = (ViewHolder) v.getTag();
}
new DownloadImageTask(holder.imageview).execute(receptisList.get(position).getSlika());
holder.tvName.setText(receptisList.get(position).getNaziv());
return v;
}
static class ViewHolder {
public TextView tvName;
public ImageView imageview;
}
protected class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
ImageView bmImage;
public DownloadImageTask(ImageView bmImage) {
this.bmImage = bmImage;
}
protected Bitmap doInBackground(String... urls) {
String urldisplay = urls[0];
Bitmap mIcon11 = null;
try {
InputStream in = new java.net.URL(urldisplay).openStream();
mIcon11 = BitmapFactory.decodeStream(in);
} catch (Exception e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return mIcon11;
}
protected void onPostExecute(Bitmap result) {
bmImage.setImageBitmap(result);
}
}
}

ListView Not Working On Real Device

I have a problem with my listview, it works on emulator but not on real device. I tested with 2 real devices and it does not populate. I get listview data from database using json. Json result is ok as it prints to logcat and populates listview on emulator.
ListView Java:
public class ActivityRequestsFrom extends MainActivity implements AdapterView.OnItemClickListener {
______________________________________________________________________________
Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_requests_from);
lv = (ListView) findViewById(R.id.listRequests);
RequestsAdapter adapter = new RequestsAdapter(this, arrRequest_Name, arrRequest_Number,
arrRequest_Username, arrRequest_Result, imageId);
lv.setAdapter(adapter);
lv.setOnItemClickListener(this);
}
______________________________________________________________________________
class RequestsAdapter extends ArrayAdapter<String>
{
Context context;
List<String> Request_Name;
List<String> Request_Number;
List<String> Request_Username;
List<String> Request_Result;
Integer[] imgid;
RequestsAdapter(Context c, List<String> Request_Name,
List<String> Request_Number, List<String> Request_Username,
List<String> Request_Result, Integer[] imgid)
{
super(c, R.layout.activity_requests_single, R.id.textName, Request_Name);
this.context=c;
this.Request_Name=Request_Name;
this.Request_Number=Request_Number;
this.Request_Username=Request_Username;
this.Request_Result=Request_Result;
this.imgid=imgid;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
View row=convertView;
if(row==null)
{
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
row = inflater.inflate(R.layout.activity_requests_single, parent, false); }
TextView txtName = (TextView) row.findViewById(R.id.textName);
TextView txtNumber = (TextView) row.findViewById(R.id.textNumber);
TextView txtUsername = (TextView) row.findViewById(R.id.textUsername);
TextView txtResult = (TextView) row.findViewById(R.id.textResult);
ImageView imageView = (ImageView) row.findViewById(R.id.imageView);
Map<String, Integer> drawableMap = new HashMap<String, Integer>();
drawableMap.put("ok",R.drawable.request_pending_from);
drawableMap.put("pending",R.drawable.request_pending_from);
drawableMap.put("rejected",R.drawable.request_rejected_from);
drawableMap.put("blocked",R.drawable.request_blocked_from);
txtName.setText(Request_Name.get(position));
txtNumber.setText(Request_Number.get(position));
txtUsername.setText(Request_Username.get(position));
txtResult.setText(Request_Result.get(position));
//imageView.setImageResource(imgid[position]);
imageView.setImageResource(drawableMap.get(Request_Result.get(position).toLowerCase()));
return row;
}
}
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// TODO Auto-generated method stub
TextView tvUsername = (TextView) view.findViewById(R.id.textUsername);
usernameSelected = tvUsername.getText().toString();
TextView tvResult = (TextView) view.findViewById(R.id.textResult);
resultSelected = tvResult.getText().toString();
if (resultSelected.equals("Pending"))
{
pendingOptions();
}
else if (resultSelected.equals("Rejected"))
{
rejectedOptions();
}
else if (resultSelected.equals("Blocked"))
{
blockedOptions();
}
else
{
}
}
ListView Layout:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<ListView
android:id="#+id/listRequest"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
</ListView>
ListView Single Layout
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<TextView
android:id="#+id/textName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="#+id/LLdummy"
android:text="Name"
android:textAppearance="?android:attr/textAppearanceLarge"
android:textStyle="italic"
android:layout_marginLeft="10dp"
/>
<TextView
android:id="#+id/textUsername"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/textNumber"
android:layout_alignParentRight="true"
android:layout_below="#+id/textNumber"
android:text="Username"
android:textAppearance="?android:attr/textAppearanceSmall" />
<TextView
android:id="#+id/textNumber"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/textName"
android:layout_below="#+id/textName"
android:text="Number"
android:textAppearance="?android:attr/textAppearanceSmall"
android:textStyle="bold" />
<ImageView
android:id="#+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignRight="#+id/LLdummy"
android:layout_centerVertical="true"
android:src="#drawable/request_pending_to" />
Json
private class JsonReadTask extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... params) {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(params[0]);
try {
HttpResponse response = httpclient.execute(httppost);
jsonResult = inputStreamToString(response.getEntity().getContent()).toString();
}
catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
private StringBuilder inputStreamToString(InputStream is) {
String rLine = "";
StringBuilder answer = new StringBuilder();
BufferedReader rd = new BufferedReader(new InputStreamReader(is));
try {
while ((rLine = rd.readLine()) != null) {
answer.append(rLine);
}
}
catch (IOException e) {
// e.printStackTrace();
Toast.makeText(getApplicationContext(),"Error..." + e.toString(), Toast.LENGTH_LONG).show();
}
return answer;
}
#Override
protected void onPostExecute(String result) {
try{
ListDrwaer(); //has ConnectionException (when it cannot reach server)
}catch (Exception e){
Toast.makeText(getApplicationContext(), "Please check your connection..", Toast.LENGTH_LONG).show();
}
}
}// end async task
public void accessWebService() {
JsonReadTask task = new JsonReadTask();
// passes values for the urls string array
task.execute(new String[] { "http://server/file.php?pIMEI="+IMEI });
}
// build hash set for list view
public void ListDrwaer() {
try {
JSONObject jsonResponse = new JSONObject(jsonResult);
JSONArray jsonMainNode = jsonResponse.optJSONArray("request_info");
for (int i = 0; i < jsonMainNode.length(); i++) {
JSONObject jsonChildNode = jsonMainNode.getJSONObject(i);
String request_name = jsonChildNode.optString("Request_Name");
String request_number = jsonChildNode.optString("Request_Number");
String request_username = jsonChildNode.optString("Request_Username");
String request_result = jsonChildNode.optString("Request_Result");
arrRequest_Name.add(request_name);
arrRequest_Number.add(request_number);
arrRequest_Username.add(request_username);
arrRequest_Result.add(request_result);
System.out.println("Request_Name: "+request_name);
System.out.println("Request_Number: "+request_number);
System.out.println("Request_Username: "+request_username);
System.out.println("Request_Result: "+request_result);
}
} catch (JSONException e) {
System.out.println("Json Error Requests" +e.toString());
Toast.makeText(getApplicationContext(), "No Requests Pending", Toast.LENGTH_SHORT).show();
}
}
Call Async
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_requests_from);
...
accessWebService();
//ListView
lv = (ListView) findViewById(R.id.listRequests);
RequestsAdapter adapter = new RequestsAdapter(this, arrRequest_Name, arrRequest_Number, arrRequest_Username, arrRequest_Result, imageId);
lv.setAdapter(adapter);
lv.setOnItemClickListener(this);

The problem here is that the data isn't received when the Adapter is set on the ListView. This is because the data is populated in an AysncTask which is async hronous by nature. This means that it will run in the background while the other code runs (i.e. the ListView populating.
So, in onPostExecute() you need to use notifyDataSetChanged() to let the ListView know that there is new items to populate.
#Override
protected void onPostExecute(String result) {
// your code
adapter.notifyDataSetChanged(); // this line here
}// end async task
In your example, this will obviously require you making the Adapter a member variable or passing it to your AsyncTask.

Image doesn't show in ImageView

I've tried may be every solution from here but nothing helped me. The image doesn't show on the listview only the text. I got only this in LogCat
11-04 14:46:29.319: I/(1225): {"Restaurants":[{"id":"1","name":"Restaurant- 1","menu":"Restaurant-1","image":"rest1.jpg"},{"id":"2","name":"Restaurant-2","menu":"Restaurant-2","image":"rest2.jpg"},{"id":"3","name":"Restaurant-3","menu":"Restaurant-3","image":"rest3.jpg"},{"id":"4","name":"Restaurant-4","menu":"Restaurant-4","image":"rest4.jpg"}]}
11-04 14:46:29.329: E/err(1225): rest1.jpg Restaurant-1 Restaurant-1
11-04 14:46:29.329: E/err(1225): rest2.jpg Restaurant-2 Restaurant-2
11-04 14:46:29.329: E/err(1225): rest3.jpg Restaurant-3 Restaurant-3
11-04 14:46:29.329: E/err(1225): rest4.jpg Restaurant-4 Restaurant-4
This is the code
public class Restaurants extends Activity {
ListView listView;
private StockAdaptor stockAdaptor;
String jsonResult = null;
ImageView image;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.restaurants);
listView = (ListView) findViewById(android.R.id.list);
image = (ImageView) findViewById(R.id.image);
new JsonReadTask().execute("http://link/GetRestaurants.php");
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
return true; //No options
}
public void onStart() {
super.onStart();
stockAdaptor = new StockAdaptor(this); //Create a new StockAdaptor
}
public static String strFromStream(InputStream in) throws IOException { //Simple function, getting a String from an InputStream
StringBuilder out = new StringBuilder();
BufferedReader breader = new BufferedReader(new InputStreamReader(in));
String cline;
String newLine = System.getProperty("line.separator");
while ((cline = breader.readLine()) != null) {
out.append(cline);
out.append(newLine);
}
return out.toString();
}
private class StockAdaptor extends BaseAdapter { //The stocks list adaptor
class ViewHolder {
TextView name;
TextView menu;
ImageView image;
}
private LayoutInflater layoutInflater;
private RestaurantInformation[] stocks = null; //Array of stocks
private ListView stocksListView = null;
public StockAdaptor(Context context) {
super();
layoutInflater = LayoutInflater.from(context);
}
public void setStockList(RestaurantInformation[] stocksinfo) {
this.stocks = stocksinfo;
}
#Override
public int getCount() {
return stocks.length;
}
#Override
public Object getItem(int position) {
return stocks[position];
}
public RestaurantInformation[] getAll() { //Return the array of stocks
return stocks;
}
#Override
public long getItemId(int position) {
return 0;
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder; //New holder
if (convertView == null) {
convertView = layoutInflater.inflate(R.layout.restaurant_information, null);
holder = new ViewHolder();
// Creates the new viewHolder define above, storing references to the children
holder.name = (TextView) convertView.findViewById(R.id.name);
holder.menu = (TextView) convertView.findViewById(R.id.menu);
holder.image = (ImageView) convertView.findViewById(R.id.image);
if (holder.image != null) {
if (holder.image.getDrawable() == null) {
new ImageDownloaderTask(holder.image, null)
.execute(stocks[position].image); //Download the image using the image
}
}
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.name.setText(stocks[position].name);
holder.menu.setText(stocks[position].menu);
return convertView;
}
}
private class JsonReadTask extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... params) {
if (URLUtil.isValidUrl(params[0])) {
final AndroidHttpClient client = AndroidHttpClient.newInstance("Android");
final HttpGet getRequest = new HttpGet(params[0]);
try {
HttpResponse response = client.execute(getRequest);
final HttpEntity httpentity = response.getEntity();
if (httpentity != null){
InputStream inputStream = null;
try {
inputStream = httpentity.getContent();
jsonResult = strFromStream(inputStream);
Log.i("", jsonResult);
return jsonResult;
} catch (IllegalArgumentException e) {
//
} finally {
httpentity.consumeContent();
}
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
client.close();
}
}
return null;
}
#Override
protected void onPostExecute(String result) {
ListDrwaer();
}
}// end async task
// build hash set for list view
public void ListDrwaer() {
//Log.d("data from server", "data: " + jsonResult.toString());
try {
if (jsonResult!=null) {
JSONObject jsonResponse = new JSONObject(jsonResult);
JSONArray jsonMainNode = jsonResponse.optJSONArray("Restaurants");
Vector<RestaurantInformation> vstocks = new Vector<RestaurantInformation>();
if(jsonMainNode == null)
{
Log.e("If is null", "jsonMainNode is null");
return;
}
for (int i = 0; i < jsonMainNode.length(); i++) {
JSONObject jsonChildNode = jsonMainNode.getJSONObject(i);
RestaurantInformation stock = new RestaurantInformation();
stock.image = jsonChildNode.getString("image");
stock.name = jsonChildNode.optString("name");
stock.menu = jsonChildNode.optString("menu");
//stock.imgPath = jsonChildNode.getString("imgPath");
Log.e("err", stock.image + " " + stock.name + " " + stock.menu);
vstocks.add(stock);
}
RestaurantInformation[] stocks = new RestaurantInformation[jsonMainNode.length()];
int stockscount = jsonMainNode.length();
for (int n = 0; n < stockscount; n++)
{
stocks[n] = vstocks.get(n);
}
stockAdaptor.setStockList(stocks);
listView.setAdapter(stockAdaptor);
} else {
Toast.makeText(getApplicationContext(), "Error; jsonResult null",
Toast.LENGTH_SHORT).show();
}
} catch (JSONException e) {
Toast.makeText(getApplicationContext(), "Error" + e.toString(),
Toast.LENGTH_SHORT).show();
}
}
private class ImageDownloaderTask extends AsyncTask<String, Void, Bitmap> {
private final WeakReference<ImageView> imageViewReference;
public ImageDownloaderTask(ImageView imageView, View view) {
imageViewReference = new WeakReference<ImageView>(imageView);
}
#Override
// Actual download method, run in the task thread
protected Bitmap doInBackground(String... params) {
// params comes from the execute() call: params[0] is the url.
return downloadBitmap(params[0]);
}
#Override
// Once the image is downloaded, associates it to the imageView
protected void onPostExecute(Bitmap bitmap) {
if (isCancelled()) {
bitmap = null;
}
if (imageViewReference != null) {
ImageView imageView = imageViewReference.get();
if (imageView != null) {
if (bitmap != null) {
imageView.setImageBitmap(bitmap);
} else {
//
}
}
}
}
Bitmap downloadBitmap(String url) {
if(URLUtil.isValidUrl(url)){
final AndroidHttpClient client = AndroidHttpClient.newInstance("Android");
final HttpGet getRequest = new HttpGet(url);
try {
HttpResponse response = client.execute(getRequest);
final int statusCode = response.getStatusLine().getStatusCode();
if (statusCode != HttpStatus.SC_OK) {
Log.w("ImageDownloader", "Error " + statusCode
+ " while retrieving bitmap from " + url);
return null;
}
final HttpEntity entity = response.getEntity();
if (entity != null) {
InputStream inputStream = null;
try {
inputStream = entity.getContent();
try {
byte[] buffer = new byte[8192];
int bytesRead;
ByteArrayOutputStream output = new ByteArrayOutputStream();
while ((bytesRead = inputStream.read(buffer)) != -1) {
output.write(buffer, 0, bytesRead);
}
return BitmapFactory.decodeByteArray(output.toByteArray(), 0, output.toByteArray().length);
} catch (IllegalArgumentException e) {
e.printStackTrace();
return null;
}
} finally {
if (inputStream != null) {
inputStream.close();
}
entity.consumeContent();
}
}
} catch (Exception e) {
getRequest.abort();
Log.w("ImageDownloader", "Error while retrieving bitmap from " + url);
} finally {
if (client != null) {
client.close();
}
}
return null;
}
return null;
}
}
}
I'm not so experienced in Java+Android and really have no idea what can be the problem.
This is the restaurants.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"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".Activity" >
<ImageView
android:id="#+id/image"
android:layout_width="70dp"
android:layout_height="70dp" />
<ListView
android:id="#id/android:list"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_alignLeft="#+id/image"
android:layout_alignParentTop="true" >
</ListView>
</RelativeLayout>
UPDATE
The goal is something like this. I want to load image on the left side and next to it to have text and sub-text if is possible
UPDATE restaurant_information.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:minHeight="50dp"
android:orientation="vertical" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<ImageView
android:id="#+id/image"
android:layout_width="70dp"
android:layout_height="70dp" />
<TextView
android:id="#+id/name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:lineSpacingExtra="3dp"
android:paddingLeft="5dp"
android:paddingTop="5dp"
android:text="" />
<TextView
android:id="#+id/menu"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingLeft="5dp"
android:paddingTop="5dp"
android:text="" />
</LinearLayout>

Your ListView is defined as layout_width="fill_parent" and layout_height="fill_parent". As such, it will take up the entire area of it's parent and since it is defined last in the layout, will be at the top of the z-order thereby obscuring your ImageView.
Give this a try:
<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"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".Activity" >
<ImageView
android:id="#+id/image"
android:layout_width="70dp"
android:layout_height="70dp"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"/>
<ListView
android:id="#id/android:list"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_toRightOf="#+id/image"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true" >
</ListView>
</RelativeLayout>

You're trying to download the picture from: "rest1.jpg". You need a complete URL.
You can either send the complete url inside the json response, or add it inside your code (if the part that comes before the filename is fixed)

Parsing JSON Data to a list View

I am trying to parse the data into the list View in android
JSON:: http://54.218.73.244:7000/
It has a JSON output :: [{"restaurantID":1,"restaurantNAME":"CopperChimney"},{"restaurantID":2,"restaurantNAME":"Aroy"},{"restaurantID":3,"restaurantNAME":"MarkBoulevard"}]
I am trying to display the CopperChimney, Aroy, MarkBoulevard in a
list view
I figured some small parts but can someone help me fill
AndroidJSONParsingActivity.java part of the code which invoolves putting data in a collection and displaying it
Any ideas ?
JSONParser
public class JSONParser {
static InputStream is = null;
static JSONArray jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONArray getJSONFromUrl(String url) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONArray(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
Item.java
public class Item{
private String Name;
public Item(String name){
this.Name = name;
}
public String getName(){
return Name;
}
}
ListAdapter.java
public class ListAdapter extends ArrayAdapter<Item> {
private List<Item> items;
public ListAdapter(Context context, int resource, List<Item> items) {
super(context, resource, items);
this.items = items;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
TextView tt = null;
if (v == null) {
LayoutInflater vi;
vi = LayoutInflater.from(getContext());
v = vi.inflate(R.layout.itemlistrow, null);
tt = (TextView) v.findViewById(R.id.RestaurantNameID);
}
Item p = items.get(position);
if (p != null) {
if (tt != null) {
tt.setText(""+p.getName());
}
}
return v;
}
}
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<ListView
android:id="#+id/listViewID"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_gravity="center">
</ListView>
</LinearLayout>
itemlistrow.xml
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="wrap_content" android:orientation="vertical"
android:layout_width="fill_parent">
<TableRow android:layout_width="fill_parent"
android:id="#+id/TableRow01"
android:layout_height="wrap_content">
<TextView
android:id="#+id/RestaurantNameID"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="name" android:textStyle="bold"
android:gravity="left"
android:layout_weight="1"
android:typeface="monospace"
android:height="40sp"/>
</TableRow>
</TableLayout>
AndroidJSONParsingActivity.java
public class AndroidJSONParsingActivity extends Activity {
private static String url = "http://54.218.73.244:7000/";
//
//
//
//
/------ CODE -Trying to ADD ------ /
//
//
}
CODE I TRIED FOR AndroidJSONParsingActivity.java
public class AndroidJSONParsingActivity extends Activity {
// url to make request
private static String url = "http://54.218.73.244:7000/";
List<Item> yourData = new ArrayList<Item>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Creating JSON Parser instance
JSONParser jParser = new JSONParser();
// getting JSON string from URL
JSONArray json = jParser.getJSONFromUrl(url);
try {
for (int i = 0; i < json.length(); i++) {
JSONObject c = json.getJSONObject(i);
// Storing each json item in variable
String NAME=c.getString("restaurantNAME");
yourData.add(new Item(NAME));
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
ListView yourListView = (ListView) findViewById(R.id.listViewID);
ListAdapter customAdapter = new ListAdapter(this, R.layout.itemlistrow, yourData);
yourListView.setAdapter(customAdapter);
yourListView.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// When clicked, show a toast with the TextView text
if(position == 0)
{
//code specific to first list item
Intent myIntent = new Intent(AndroidJSONParsingActivity.this,Employee1.class);
startActivity(myIntent);
}else if(position == 1)
{
Intent myIntent = new Intent(AndroidJSONParsingActivity.this,Employee2.class);
startActivity(myIntent);
}
}
});
}
}

public class AndroidJSONParsingActivity extends ListActivity {
ArrayList <Item> list = new ArraList <Item>();
#Override
public void onStart() {
super.onStart();
new GetHttpData().execute();
}
private class GetHttpData extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... params) {
private static String url = "http://54.218.73.244:7000/";
JSONArray jArray = getJSONFromUrl(url);
int len = jArray.length();
for(int i = 0; i < len; i++) {
JSONObject restaurant = jArray.getJSONObject(i);
list.add(new Item(restaurant.getString("restaurantNAME"));
}
return null;
}
#Override
protected void onPostExecute(Void result) {
setListAdapter(new ListAdapter(AndroidJSONParsingActivity.this, android.R.layout.simple_list_item_1, list));
}
}
}
This is just one way to parse it, you should also do all HttpRequests and JSON parsing in a separate thread, see http://developer.android.com/reference/android/os/AsyncTask.html
Edited:
You can also check this Example