I have the following code:
protected void onCreate(Bundle savedInstanceState) {
RecyclerView recyclerView;
DeviceAdapter deviceAdapter;
List<Device> deviceList;
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final Context context = this;
g.IP = cf.getIP(this);
g.subNet = g.IP.substring(0, g.IP.lastIndexOf(".") + 1);
deviceList = new ArrayList<>();
recyclerView = findViewById(R.id.recyclerView);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
new AsyncTask<Void, Void, Void>() {
#Override
protected Void doInBackground(Void... params) {
for(int i = 1; i < 256; i++) {
if(cf.isUp(g.subNet + i, 80)) {
deviceList.add(new Device(g.subNet + i, "PAUSED", "N/A"));
}
}
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
deviceAdapter = new DeviceAdapter(context, deviceList);
recyclerView.setAdapter(deviceAdapter);
}
}.execute();
}
Which checks if a host is online, and if their port 80 is open, then at the end of the scan, it adds them all to the RecyclerView.
I was wondering how I could add:
deviceAdapter = new DeviceAdapter(context, deviceList);
recyclerView.setAdapter(deviceAdapter);
to the doInBackground() if statement, like this:
#Override
protected Void doInBackground(Void... params) {
for(int i = 1; i < 256; i++) {
if(cf.isUp(g.subNet + i, 80)) {
deviceList.add(new Device(g.subNet + i, "UP", "OPEN"));
deviceAdapter = new DeviceAdapter(context, deviceList);
recyclerView.setAdapter(deviceAdapter);
}
}
return null;
}
but without it crashing my app, so that the RecyclerView updates straight away when a new item is added to deviceList<>, rather then when the task is finished.
Your app is crashing because only the main thread can handle UI elements such as RecyclerView. So what you need to do is create a listener that will be called whenever your AsyncTask finds a new device.
Example:
public interface OnDeviceFoundListener {
void onDeviceFound(Device device);
}
#Override
protected void doInBackground(Void... params) {
for (int i = 1; i < 256; i++) {
if (cf.isUp(g.subNet + 1, 80)) {
listener.onDeviceFound(new Device(g.subNet + 1, "UP", "OPEN"));
}
}
}
Then, in the Activity or Fragment where the RecyclerView is located, you will implement this listener interface, for example:
public class MyActivity extends AppCompatActivity implements OnDeviceFoundListener {
private List<Device> devices;
#Override
public void onDeviceFound(Device device) {
devices.add(device);
deviceAdapter = new DeviceAdapter(context, devices);
recyclerView.setAdapter(adapter);
recyclerView.getAdapter().notifyDataSetChanged();
}
}
Don't forget to call the notifyDataSetChanged method in your adapter after you add the new device(s) you add.
Related
I am using Timertask for scrolling images with viewpager. I need to show all images after that it is automatically move to category wise (no click operation).
public class GalleryActviity extends AppCompatActivity {
Timer timer;
LinearLayout images_lay;
ArrayList<String> arraylist = new ArrayList<String>();
List<String> tempimages = new ArrayList<String>();
ViewPager mPager ;
private static int currentPage = 0
List<String> dealimages = new ArrayList<>();
ArrayList<DetailImage> detail_images = new ArrayList<DetailImage>();
#Override
protected void onCreate( Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_gallery);
images_lay =(LinearLayout)findViewById(R.id.images_lay);
mPager = (ViewPager) findViewById(R.id.pager);
Intent in = getIntent();
Log.v("Tag_resid",""+in.getStringExtra("restid"));
String restid = in.getStringExtra("restid");
restaurntrestid(restid);
}
private void restaurntrestid(String restid) {
ServiceClient serviceClient = ServiceUtil.getServiceClient();
serviceClient.restaurntrestid(restid, restidcallback);
}
Callback<JsonObject> restidcallback = new Callback<JsonObject>() {
#Override
public void success(final JsonObject cusinerestaurantsinfo, Response response) {
imagesDeatail(cusinerestaurantsinfo);
}
#Override
public void failure(RetrofitError error) {
}
};
private void imagesDeatail(JsonObject cusinerestaurantsinfo) {
try {
JsonArray restaurant_imagesarray = cusinerestaurantsinfo.get("restaurant_images")
.getAsJsonArray();
for (int i = 0; i < restaurant_imagesarray.size(); i++) {
String url = restaurant_imagesarray.get(i).getAsJsonObject().get("url").getAsString();
String type = restaurant_imagesarray.get(i).getAsJsonObject().get("type").getAsString();
if(!arraylist.contains(type)){
arraylist.add(type);
// type means category like food, menu, logo...etc(dynamic data)
}
dealimages.add(url);
DetailImage detail = new DetailImage();
detail.setType(type);
detail.setUrl(url);
detail_images.add(detail);
}
mPager.setAdapter(new DealAdapter(GalleryActviity.this, dealimages));
imageRotator(1);
imageshow();
} catch (Exception e) {
e.printStackTrace();
}
}
public void imageRotator(int seconds) {
currentPage = 0;
timer = new Timer();
timer.scheduleAtFixedRate(new ImageRotateTask(), 0, seconds * 3000);
}
class ImageRotateTask extends TimerTask {
#Override
public void run() {
runOnUiThread(new Runnable() {
public void run() {
if (currentPage == dealimages.size() ) {
timer.cancel();
//Something here
}
else {
mPager.setCurrentItem(currentPage++, true);
}
}
});
}
}
private void imageshow(){
for(int i = 0; i < arraylist.size(); i++) {
final Button txtview = new Button(this);
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT);
layoutParams.setMargins(0, 0, 0, 0);
if(i == 0){
txtview.setText("All");
txtview.setBackgroundColor(getResources().getColor(R.color.navigationBarwhite));
txtview.setTextColor(getResources().getColor(R.color.colorPrimary));
}
else {
txtview.setText(arraylist.get(i));
txtview.setBackgroundColor(getResources().getColor(R.color.navigationBarwhite));
txtview.setTextColor(getResources().getColor(R.color.navigationBarColor));
}
txtview.setLayoutParams(layoutParams);
txtview.setTextSize(12);
txtview.setAllCaps(false);
txtview.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(!txtview.getText().toString().equalsIgnoreCase("All")){
//image_display(txtview.getText().toString().trim());
txtview.setBackgroundColor(getResources().getColor(R.color.navigationBarwhite));
txtview.setTextColor(getResources().getColor(R.color.colorPrimary));
}
else if(txtview.getText().toString().equalsIgnoreCase("All")){
imageRotator(1);
mPager.setAdapter(new DealAdapter(GalleryActviity.this, dealimages));
}
}
});
images_lay.addView(txtview);
}
}
}
Here i am showing all the images in "ALL" section. how to show the remain images of every catgory. I added my screenshot which will show the images . "ALL" means every category type image will showing in this section.
Here i can showing all images in "ALL" Section, now how to move to automatically show the images based on category.
I am fetching data from json with Volley and populating RecyclerView with the parsed data but I ran into a bit of problem:
The call to get the items is in onCreate method, so the call is repeated each time the activity is recreated both from configuration changes and otherwise; hence the data is reloaded. So I found this answer that uses parcelables
and this article on Codepath (still on parcelables). After I have followed the instructions explicitly (or so I feel), there seems to be no change: the call to get data is repeated each time the activity is recreated.
FruitItems
public class FruitItems implements Parcelable {
private String fruit_title;
private String fruit_description;
private String fruit_image;
public String getFruit_title() {
return fruit_title;
}
public void setFruit_title(String fruit_title) {
this.fruit_title = fruit_title;
}
public String getFruit_description() {
return fruit_description;
}
public void setFruit_description(String fruit_description) {
this.fruit_description = fruit_description;
}
public String getFruit_image() {
return fruit_image;
}
public void setFruit_image(String fruit_image) {
this.fruit_image = fruit_image;
}
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(this.fruit_title);
dest.writeString(this.fruit_description);
dest.writeString(this.fruit_image);
}
public FruitItems() {
}
protected FruitItems(Parcel in) {
this.fruit_title = in.readString();
this.fruit_description = in.readString();
this.fruit_image = in.readString();
}
public static final Parcelable.Creator<FruitItems> CREATOR = new Parcelable.Creator<FruitItems>() {
#Override
public FruitItems createFromParcel(Parcel source) {
return new FruitItems(source);
}
#Override
public FruitItems[] newArray(int size) {
return new FruitItems[size];
}
};
}
MainActivity
public class MainActivity extends AppCompatActivity {
private final String TAG = "MainActivity";
private final String KEY_POST_ITEMS = "fruititems";
//List of fruits
private List<FruitItems> mFruitItemsList;
//Views
private RecyclerView recyclerView;
private RecyclerView.Adapter adapter;
private ProgressDialog mProgressDialog;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.d(TAG, "onCreate called");
//Initializing Views
recyclerView = (RecyclerView) findViewById(R.id.fruit_recycler);
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
if (savedInstanceState != null && savedInstanceState.containsKey(KEY_POST_ITEMS)) {
mFruitItemsList = savedInstanceState.getParcelableArrayList(KEY_POST_ITEMS);
} else {
//Initializing the fruitlist
mFruitItemsList = new ArrayList<>();
if (NetworkCheck.isAvailableAndConnected(this)) {
getData();
} else {
final Context mContext;
mContext = this;
final AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
alertDialogBuilder.setTitle(R.string.alert_titl);
alertDialogBuilder.setCancelable(false);
alertDialogBuilder.setIcon(R.mipmap.ic_launcher);
alertDialogBuilder.setMessage(R.string.alert_mess);
alertDialogBuilder.setPositiveButton(R.string.alert_retry, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
if (!NetworkCheck.isAvailableAndConnected(mContext)) {
alertDialogBuilder.show();
} else {
getData();
}
}
});
alertDialogBuilder.setNegativeButton(R.string.alert_cancel, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
finish();
}
});
alertDialogBuilder.show();
}
}
adapter = new FruitAdapter(mFruitItemsList, this);
recyclerView.setAdapter(adapter);
}
#Override
public void onSaveInstanceState(Bundle savedInstanceState) {
savedInstanceState.putParcelableArrayList(KEY_POST_ITEMS, ArrayList<? extends Parcelable>))mFruitItemsList);
super.onSaveInstanceState(savedInstanceState);
}
//Getting json data
private void getData(){
Log.d(TAG, "getData called");
//Show progress dialog
mProgressDialog = new ProgressDialog(MainActivity.this);
mProgressDialog.setCancelable(false);
mProgressDialog.setMessage(this.getResources().getString(R.string.load_fruit));
mProgressDialog.show();
//Creating a json request
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(ConfigFruit.GET_URL,
new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
Log.d(TAG, "onResponse called");
//Dismissing the progress dialog
if (mProgressDialog != null) {
mProgressDialog.hide();
}
//calling method to parse json array
parseData(response);
}
},
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
});
//Creating request queue
RequestQueue requestQueue = Volley.newRequestQueue(this);
//Adding request to the queue
requestQueue.add(jsonArrayRequest);
}
//parsing json data
private void parseData(JSONArray array){
Log.d(TAG, "Parsing array");
for(int i = 0; i<array.length(); i++) {
FruitItems fruitItem = new FruitItems();
JSONObject jsonObject = null;
try {
jsonObject = array.getJSONObject(i);
fruitItem.setFruit_title(jsonObject.getString(ConfigFruit.TAG_POST_TITLE));
fruitItem.setFruit_description(jsonObject.getString(ConfigFruit.TAG_POST_DESCRIPTION));
//Parsing image
JSONObject fruitImage = jsonObject.getJSONObject("thumbnail");
fruitItem.setFruit_image(fruitImage.getString("url"));
} catch (JSONException w) {
w.printStackTrace()
}
mFruitItemsList.add(fruitItem);
}
adapter.notifyItemRangeChanged(0, adapter.getItemCount());
}
}
I may not be a pro but I know that I have goofed somewhere in the codes above, else it should have worked.
Now, my question is where did I goof and how do I plug this mistake?
EDIT
I have edited the codes above to reflect the answer that I accepted. It works fine but there is still a problem.
I start Activity B from MainActivity. If I press the back-button in Activity B the data is saved but when I press the up-button, the getData is called again and the data is re-fetched.
Please, is there anyway around this?
You don't seem to have an onSaveInstanceState in your mainactivity. You need something like
#Override
protected void onSaveInstanceState (Bundle outState) {
super.onSaveInstanceState(outState);
outState.putParcelableArrayList(KEY_POST_ITEMS,mFruitItemsList) ;
}
In order to retain your data for the activity that is about to be destructed and the one that is being created, you need to override the onSaveInstance callback
#Override
public void onSaveInstanceState(Bundle savedInstanceState) {
savedInstanceState.putParcelableArrayList(KEY_POST_ITEMS, (ArrayList)mFruitItemsList);
super.onSaveInstanceState(savedInstanceState);
}
NOTE: always remember to call the superclass.
I have a ListView which I populate with data from DataStore or from my local database.
I am checking some condition that will determine whether I will fetch data from the DataStore or database. When I fetch from the database the ListView automatically refreshes itself, but when I fetch from the DataStore it does not. I then have to click my TextView, which is below ListView, and when I click it the soft keyboard appears and then my ListView is populated with data from DataStore.
My activity that has the ListView:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_xyz);
list_View = (ListView) findViewById(R.id.data_listView);
list_View.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE_MODAL);
list_View.setMultiChoiceModeListener(new Selector());
adapter = new MyAdapter(context,Long.valueOf(id),isOnline());
list_View.setAdapter(adapter);
list_View.setSelection(adapter.getCount() - 1);
adapter.registerDataSetObserver(new DataSetObserver() {
#Override
public void onChanged() {
super.onChanged();
list_View.setSelection(adapter.getCount() - 1);
}
LoadDataTask ldt = new LoadDataTask();
ldt.execute("123456789");
}
private void loadDataFromDataStore(final Long contactId){
final ArrayList<Data> data = new ArrayList<>();;
d("loadingdataFromDatasore");
GetDataTask task = new GetDataTask(new ApiTask.ResultListener() {
#Override
public void successHook(Object o) {
if (o instanceof GetDataResponse) {
GetDataResponse res = (GetDataResponse) o;
if (res.getData() != null && res.getData().getItems() != null) {
for (ListDataItem i : res.getData().getItems()) {
Data dp = new Data(i.getPosition(), i.getMessage(), i.getDateCreated(),i.getMessageId(),1);
adapter.addFromOtherThread(dp);
}
}
d("Messages loaded from server: " + adapter.getCount());
}
}
}
public class LoadDataTask extends AsyncTask<String,String,Void> {
#Override
protected Void doInBackground(String... params){
if(isOnline && isFirstTime){
loadDataFromDataStore(Long.valueOf(params[0]));
}else{
//load from database
}
return null;
}
#Override
protected void onPostExecute(Void v){
adapter.notifyDataSetChanged();
}
}
My adapter class that extends BaseAdapter (I have removed unnecessary code for this question):
public class DataAdapter extends BaseAdapter {
private ArrayList<Data>data_list;
public DataAdapter(){
data_list = new ArrayList<>();
}
public void addFromOtherThread(Data object) {
data_list.add(object);
}
What am I missing that is making listview not to automatically refresh itself even after calling notifyDatasetChanged()?
change :
#Override
protected void onPostExecute(Void v){
adapter.notifyDataSetChanged();
}
}
to:
#Override
protected void onPostExecute(Void v){
adapter.notifyDataSetChanged();
list_View.setAdapter(adapter);
}
}
Let me know if more clarification is required by commenting below.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_xyz);
list_View = (ListView) findViewById(R.id.data_listView);
list_View.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE_MODAL);
list_View.setMultiChoiceModeListener(new Selector());
adapter = new MyAdapter(context,Long.valueOf(id),isOnline());
list_View.setAdapter(adapter);
list_View.setSelection(adapter.getCount() - 1);
adapter.registerDataSetObserver(new DataSetObserver() {
#Override
public void onChanged() {
super.onChanged();
list_View.setSelection(adapter.getCount() - 1);
}
loadDataFromDataStore("123456789")
}
private void loadDataFromDataStore(final Long contactId){
final ArrayList<Data> data = new ArrayList<>();;
d("loadingdataFromDatasore");
new GetDataTask(new ApiTask.ResultListener() {
#Override
public void successHook(Object o) {
if (o instanceof GetDataResponse) {
GetDataResponse res = (GetDataResponse) o;
if (res.getData() != null && res.getData().getItems() != null) {
for (ListDataItem i : res.getData().getItems()) {
Data dp = new Data(i.getPosition(), i.getMessage(), i.getDateCreated(),i.getMessageId(),1);
adapter.addFromOtherThread(dp);
}
}
d("Messages loaded from server: " + adapter.getCount());
adapter.notifyDatasetChanges();
}
}
}.execute();
}
GetDataTask should work on background internally you don't need to starts a AsyncTask from here.
If you want to use AsyncTask then your AsyncTask should wait for the result from GetDataTask which it is not doing in your code implementation.
I don't know which kind of framework you are using to making api call but your implementation seems to look wrong.
I have write the code on assumption bases if your GetDataTask is a AsyncTask or some background processor it will work perfectly.
Trying to populate data to a RecyclerView from cloud, though I get output in Main Thread, it takes time, so decided to add an AsyncTask to load items with ease and also to insert a ProgressDialog, however now it seems like code has no effect, getting an empty screen.
But the AsyncTask is getting executed, as I am able to log items in the logcat, no idea why I don't get a RecyclerView. Here is the code I use and looking for help:
public class BigBoard extends ActionBarActivity {
private List<Person> persons;
private RecyclerView rv;
private RVAdapter adapter;
private String a,b;
private ProgressDialog pr;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Parse.initialize(this, "app-id", "client-key");
setContentView(R.layout.activity_big_board);
Loader abc = new Loader();
abc.execute();
adapter = new RVAdapter(persons);
rv=(RecyclerView)findViewById(R.id.rv);
LinearLayoutManager llm = new LinearLayoutManager(this);
rv.setLayoutManager(llm);
rv.setHasFixedSize(true);
}
private class Loader extends AsyncTask<String, Integer, String> {
#Override
protected void onPreExecute() {
pr = new ProgressDialog(BigBoard.this);
pr.setProgressStyle(ProgressDialog.STYLE_SPINNER);
pr.setIndeterminate(true);
pr.setCancelable(false);
pr.setMessage("Loading Board");
pr.show();
super.onPreExecute();
}
#Override
protected void onProgressUpdate(Integer... values) {
super.onProgressUpdate(values);
}
#Override
protected String doInBackground(String... urls) {
initializeData();
initializeAdapter();
return null;
}
#Override
protected void onPostExecute(String result) {
pr.dismiss();
}
private void initializeData(){
persons = new ArrayList<>();
ParseQuery<ParseObject> query = new ParseQuery<ParseObject>("BigBoard");
query.findInBackground(new FindCallback<ParseObject>() {
public void done(List<ParseObject> credentialList, ParseException e) {
if (e == null) {
for(int i=0;i<credentialList.size();i++)
{
a=credentialList.get(i).getString("Location");
b=credentialList.get(i).getString("Feed");
persons.add(new Person(a,b));
Log.d("OUT", "So the Val::------> " +a +b);
}
} else {
Log.d("score", "Error: " + e.getMessage());
}
adapter.notifyDataSetChanged();
}
});
}
private void initializeAdapter(){
rv.setAdapter(adapter);
}
}
}
place the adapter.notifyDataSetChanged(); or rv.setAdapter(adapter);
to onPostExecute..
since onOPostExecute works on UI Thread.
Edit :
create a function inside the Adapter
public void updatePersons(List<Person> persons) {
this.persons = persons;
notifyDataSetChanged();
}
after filling the list in onPostExecute call this function the List.
I downloaded and imported the library [https://github.com/shontauro/android-pulltorefresh-and-loadmore][1]
Everything works fine. but when I try to change the code in my error output.
comment out what works. what appear below my not work. Even the logs are not shown. what am I doing wrong?
public class LoadMoreExampleActivity extends ListActivity {
// list with the data to show in the listview
private LinkedList<String> mListItems;
// The data to be displayed in the ListView
private String[] mNames = { "Fabian", "Carlos", "Alex", "Andrea", "Karla",
"Freddy", "Lazaro", "Hector", "Carolina", "Edwin", "Jhon",
"Edelmira", "Andres" };
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.loadmore);
mListItems = new LinkedList<String>();
mListItems.addAll(Arrays.asList(mNames));
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, mListItems);
setListAdapter(adapter);
// set a listener to be invoked when the list reaches the end
((LoadMoreListView) getListView())
.setOnLoadMoreListener(new OnLoadMoreListener() {
public void onLoadMore() {
// Do the work to load more items at the end of list
// here
new LoadDataTask().execute();
}
});
}
private class LoadDataTask extends AsyncTask<String, Void, String> {
String[] mass;
#Override
protected String doInBackground(String... strings) {
Document doc;
if (isCancelled()) {
return null;
}
// Simulates a background task
// try {
// Thread.sleep(1000);
// } catch (InterruptedException e) {
// }
// for (int i = 0; i < mNames.length; i++)
// mListItems.add("string"+i);
try {
doc = Jsoup.connect(link).get();
Elements eName = doc.select("name");
for (int i = 0; i < eName.size(); i++) {
mListItems.add(eName.get(i).ownText());
}
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String result) {
mListItems.add("Added after load more");
// We need notify the adapter that the data have been changed
((BaseAdapter) getListAdapter()).notifyDataSetChanged();
// Call onLoadMoreComplete when the LoadMore task, has finished
((LoadMoreListView) getListView()).onLoadMoreComplete();
super.onPostExecute(result);
}
#Override
protected void onCancelled() {
// Notify the loading more operation has finished
((LoadMoreListView) getListView()).onLoadMoreComplete();
}
}
}
And you do not forget to connect to the internet?
<uses-permission android:name="android.permission.INTERNET"/>