Vaadin auto refresh grid data's based on API call in every 30 seconds - vaadin-grid

I need to call an API every 30 seconds and need to refresh the grid with updated data. I using Server push, but I can't find the optimal solution in my case. Below is my UI code
#Route(value = UserNavigation.ROUTE)
#PreserveOnRefresh
#org.springframework.stereotype.Component
public class UserNavigation extends AppLayout {
CCUIConfig config;
#Autowired
public UserNavigation( CCUIConfig config) {
this.config = config;
addToDrawer(createAccordianMenu());
}
private Component createAccordianMenu() {
VerticalLayout scrollableLayout = new VerticalLayout();
Div kioskMonitor_div = new Div(kiosksMonitorLabel);
kioskMonitor_div.addClickListener(event -> {
try {
setContent(new Monitor(config).getDashboard());
} catch (Exception e) {
e.printStackTrace();
}
});
scrollableLayout.add(kioskMonitor_div);
return scrollableLayout;
}
}
#Push
#Route
public class Monitor extends VerticalLayout{
CCUIConfig config;
Grid<Model> grid = new Grid<>();
private FeederThread thread;
public Monitor(CCUIConfig config) {
this.config = config;
}
#Override
protected void onAttach(AttachEvent attachEvent) {
// Start the data feed thread
super.onAttach(attachEvent);
thread = new FeederThread(attachEvent.getUI(),grid);
thread.start();
}
#Override
protected void onDetach(DetachEvent detachEvent) {
thread.interrupt();
thread = null;
}
public Component getDashboard() throws IOException{
String updateddate =null;
VerticalLayout dashboardview = new VerticalLayout();
Grid.Column<Model> idColumn = grid.addColumn(Model::getid)
.setHeader(ID);
Grid.Column<Model> nameColumn = grid.addColumn(Model::getName)
.setHeader(Name);
Grid.Column<Model> memoryColumn = grid.addColumn(Model::getRefreshTime)
.setHeader(Refresh time"));
dashboardview.add(grid);
return dashboardview;
}
}
class FeederThread extends Thread {
private final com.vaadin.flow.component.UI ui;
private final Grid<Model> grid;
private final CCUIConfig config;
private int count = 30;
public FeederThread(com.vaadin.flow.component.UI ui,Grid<Model> grid) {
this.config = new CCUIConfig();
this.ui = ui;
this.grid= grid;
}
#Override
public void run() {
while (count>0){
try {
Thread.sleep(1000);
ui.access(()-> {
System.out.println("Thread Entry ");
try {
StringBuilder jsongrid = HttpClientGetRequestClient.executeUrlGet(config.getRefreshAPI());
ObjectMapper mapper = new ObjectMapper();
List<Model> userlist = new ArrayList<Model>();
String date="";
if(jsongrid!=null)
{
ModelWrapper eh = mapper.readValue(jsongrid.toString(), ModelWrapper.class);
userlist = eh.getMetricsData();
}
if(userlist != null)
{
grid.setItems(userlist);
grid.getDataProvider().refreshAll();
}
}catch(JSONException |JsonProcessingException e) {
e.printStackTrace();
}
});
count--;
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
UserNavigation is the page that loads after user login, it contains a sidebar with multiple options(or functionalities). One of the functionality is the Monitor screen.
Monitor is the page with a grid where we need to refresh it in 30 seconds.
FeederThread is the thread class that calls an API and update the data in the grid asynchronously.
As from the above code, what happens is like
onAttach(AttachEvent attachEvent)
is not getting executed so the grid is not getting displayed on the page, we use vaadin 14, any help will be appreciated.

Related

Freemarker Debugger framework usage example

I have started working on a Freemarker Debugger using breakpoints etc. The supplied framework is based on java RMI. So far I get it to suspend at one breakpoint but then ... nothing.
Is there a very basic example setup for the serverpart and the client part other then the debug/imp classes supplied with the sources. That would be of great help.
this is my server class:
class DebuggerServer {
private final int port;
private final String templateName1;
private final Environment templateEnv;
private boolean stop = false;
public DebuggerServer(String templateName) throws IOException {
System.setProperty("freemarker.debug.password", "hello");
port = SecurityUtilities.getSystemProperty("freemarker.debug.port", Debugger.DEFAULT_PORT).intValue();
System.setProperty("freemarker.debug.password", "hello");
Configuration cfg = new Configuration();
// Some other recommended settings:
cfg.setIncompatibleImprovements(new Version(2, 3, 20));
cfg.setDefaultEncoding("UTF-8");
cfg.setLocale(Locale.US);
cfg.setTemplateExceptionHandler(TemplateExceptionHandler.RETHROW_HANDLER);
Template template = cfg.getTemplate(templateName);
templateName1 = template.getName();
System.out.println("Debugging " + templateName1);
Map<String, Object> root = new HashMap();
Writer consoleWriter = new OutputStreamWriter(System.out);
templateEnv = new Environment(template, null, consoleWriter);
DebuggerService.registerTemplate(template);
}
public void start() {
new Thread(new Runnable() {
#Override
public void run() {
startInternal();
}
}, "FreeMarker Debugger Server Acceptor").start();
}
private void startInternal() {
boolean handled = false;
while (!stop) {
List breakPoints = DebuggerService.getBreakpoints(templateName1);
for (int i = 0; i < breakPoints.size(); i++) {
try {
Breakpoint bp = (Breakpoint) breakPoints.get(i);
handled = DebuggerService.suspendEnvironment(templateEnv, templateName1, bp.getLine());
} catch (RemoteException e) {
System.err.println(e.getMessage());
}
}
}
}
public void stop() {
this.stop = true;
}
}
This is the client class:
class DebuggerClientHandler {
private final Debugger client;
private boolean stop = false;
public DebuggerClientHandler(String templateName) throws IOException {
// System.setProperty("freemarker.debug.password", "hello");
// System.setProperty("java.rmi.server.hostname", "192.168.2.160");
client = DebuggerClient.getDebugger(InetAddress.getByName("localhost"), Debugger.DEFAULT_PORT, "hello");
client.addDebuggerListener(environmentSuspendedEvent -> {
System.out.println("Break " + environmentSuspendedEvent.getName() + " at line " + environmentSuspendedEvent.getLine());
// environmentSuspendedEvent.getEnvironment().resume();
});
}
public void start() {
new Thread(new Runnable() {
#Override
public void run() {
startInternal();
}
}, "FreeMarker Debugger Server").start();
}
private void startInternal() {
while (!stop) {
}
}
public void stop() {
this.stop = true;
}
public void addBreakPoint(String s, int i) throws RemoteException {
Breakpoint bp = new Breakpoint(s, i);
List breakpoints = client.getBreakpoints();
client.addBreakpoint(bp);
}
}
Liferay IDE (https://github.com/liferay/liferay-ide) has FreeMarker template debug support (https://issues.liferay.com/browse/IDE-976), so somehow they managed to use it. I have never seen it in action though. Other than that, I'm not aware of anything that uses the debug API.

How to change targetSdkVersion

I am having an issue with target targetSdkVersion.I want to move from 27 to 29 but when change to sdk 29 the app runs but does not display videos.But it displays the videos when it is sdk 27 or less.
Please can someone help me fix this.
/**
* A simple {#link Fragment} subclass.
*/
public class ChannelFragment extends Fragment {
private static String GOOGLE_YOUTUBE_API_KEY = "AIzaSyBJQYpQRTzM5wuuhMUxmP7rvP3lbMGtUZ8";//here you should use your api key for testing purpose you can use this api also
private static String CHANNEL_ID = "UCB_ZwuWCAuB7y0B93qvnkWw"; //here you should use your channel id for testing purpose you can use this api also
private static String CHANNLE_GET_URL = "https://www.googleapis.com/youtube/v3/search?part=snippet&order=date&channelId=" + CHANNEL_ID + "&maxResults=50&key=" + GOOGLE_YOUTUBE_API_KEY + "";
private RecyclerView mList_videos = null;
private VideoPostAdapter adapter = null;
private ArrayList<YoutubeDataModel> mListData = new ArrayList<>();
public ChannelFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_channel, container, false);
mList_videos = (RecyclerView) view.findViewById(R.id.mList_videos);
initList(mListData);
new RequestYoutubeAPI().execute();
return view;
}
private void initList(ArrayList<YoutubeDataModel> mListData) {
mList_videos.setLayoutManager(new LinearLayoutManager(getActivity()));
adapter = new VideoPostAdapter(getActivity(), mListData, new OnItemClickListener() {
#Override
public void onItemClick(YoutubeDataModel item) {
YoutubeDataModel youtubeDataModel = item;
Intent intent = new Intent(getActivity(), DetailsActivity.class);
intent.putExtra(YoutubeDataModel.class.toString(), youtubeDataModel);
startActivity(intent);
}
});
mList_videos.setAdapter(adapter);
}
//create an asynctask to get all the data from youtube
private class RequestYoutubeAPI extends AsyncTask<Void, String, String> {
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected String doInBackground(Void... params) {
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(CHANNLE_GET_URL);
Log.e("URL", CHANNLE_GET_URL);
try {
HttpResponse response = httpClient.execute(httpGet);
HttpEntity httpEntity = response.getEntity();
String json = EntityUtils.toString(httpEntity);
return json;
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String response) {
super.onPostExecute(response);
if (response != null) {
try {
JSONObject jsonObject = new JSONObject(response);
Log.e("response", jsonObject.toString());
mListData = parseVideoListFromResponse(jsonObject);
initList(mListData);
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
public ArrayList<YoutubeDataModel> parseVideoListFromResponse(JSONObject jsonObject) {
ArrayList<YoutubeDataModel> mList = new ArrayList<>();
if (jsonObject.has("items")) {
try {
JSONArray jsonArray = jsonObject.getJSONArray("items");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject json = jsonArray.getJSONObject(i);
if (json.has("id")) {
JSONObject jsonID = json.getJSONObject("id");
String video_id = "";
if (jsonID.has("videoId")) {
video_id = jsonID.getString("videoId");
}
if (jsonID.has("kind")) {
if (jsonID.getString("kind").equals("youtube#video")) {
YoutubeDataModel youtubeObject = new YoutubeDataModel();
JSONObject jsonSnippet = json.getJSONObject("snippet");
String title = jsonSnippet.getString("title");
String description = jsonSnippet.getString("description");
String publishedAt = jsonSnippet.getString("publishedAt");
String thumbnail = jsonSnippet.getJSONObject("thumbnails").getJSONObject("high").getString("url");
youtubeObject.setTitle(title);
youtubeObject.setDescription(description);
youtubeObject.setPublishedAt(publishedAt);
youtubeObject.setThumbnail(thumbnail);
youtubeObject.setVideo_id(video_id);
mList.add(youtubeObject);
}
}
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
return mList;
}
}

Best approach to use DiffUtil with LIveData + Room Database?

I am using Room Database with LiveData , but my Local Database is updating too fast as per our requirement and at the same time i have to reload my recycler view .instead of calling notifyDataSetChanged() to adapter , i am trying to use DiffUtil , but is crashing or not reloading properly , this is uncertain .
i am following this tutorial :
Tutorials Link here
MyAdapter :
public class SwitchGridAdapter extends RecyclerView.Adapter<SwitchGridAdapter.ViewHolder> {
private List<Object> allItemsList;
private LayoutInflater mInflater;
private OnItemClickListener mClickListener;
private Context context;
private Queue<List<Object>> pendingUpdates =
new ArrayDeque<>();
// data is passed into the constructor
public SwitchGridAdapter(Context context,List<Appliance> applianceList,List<ZmoteRemote> zmoteRemoteList) {
this.mInflater = LayoutInflater.from(context);
this.context = context;
allItemsList = new ArrayList<>();
if (applianceList!=null) allItemsList.addAll(applianceList);
if (zmoteRemoteList!=null)allItemsList.addAll(zmoteRemoteList);
}
// inflates the cell layout from xml when needed
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = mInflater.inflate(R .layout.switch_grid_item, parent, false);
return new ViewHolder(view);
}
// binds the data to the textview in each cell
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
// Doing some update with UI Elements
}
// total number of cells
#Override
public int getItemCount() {
return allItemsList.size();
}
// stores and recycles views as they are scrolled off screen
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener,View.OnLongClickListener {
TextView myTextView;
ImageView imgSwitch;
ViewHolder(View itemView) {
super(itemView);
myTextView = (TextView) itemView.findViewById(R.id.txtSwitchName);
imgSwitch = (ImageView) itemView.findViewById(R.id.imgSwitchStatus);
itemView.setOnClickListener(this);
itemView.setOnLongClickListener(this);
}
#Override
public void onClick(View view) {
// handling click
}
#Override
public boolean onLongClick(View view) {
return true;
}
// convenience method for getting data at click position
Object getItem(int id) {
return allItemsList.get(id);
}
// allows clicks events to be caught
public void setClickListener(OnItemClickListener itemClickListener) {
this.mClickListener = itemClickListener;
}
// parent activity will implement this method to respond to click events
public interface OnItemClickListener {
void onItemClick(View view, int position);
void onItemLongPressListner(View view, int position);
}
// ✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅
// From This Line Reloading with Diff Util is Done .
//✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅✅
public void setApplianceList( List<Appliance> applianceList,List<ZmoteRemote> zmoteRemoteList)
{
if (allItemsList == null)
allItemsList = new ArrayList<>();
List<Object> newAppliances = new ArrayList<>();
if (applianceList!=null) newAppliances.addAll(applianceList);
updateItems(newAppliances);
}
// when new data becomes available
public void updateItems(final List<Object> newItems) {
pendingUpdates.add(newItems);
if (pendingUpdates.size() > 1) {
return;
}
updateItemsInternal(newItems);
}
// This method does the heavy lifting of
// pushing the work to the background thread
void updateItemsInternal(final List<Object> newItems) {
final List<Object> oldItems = new ArrayList<>(this.allItemsList);
final Handler handler = new Handler();
new Thread(new Runnable() {
#Override
public void run() {
final DiffUtil.DiffResult diffResult =
DiffUtil.calculateDiff(new DiffUtilHelper(oldItems, newItems));
handler.post(new Runnable() {
#Override
public void run() {
applyDiffResult(newItems, diffResult);
}
});
}
}).start();
}
// This method is called when the background work is done
protected void applyDiffResult(List<Object> newItems,
DiffUtil.DiffResult diffResult) {
dispatchUpdates(newItems, diffResult);
}
// This method does the work of actually updating
// the backing data and notifying the adapter
protected void dispatchUpdates(List<Object> newItems,
DiffUtil.DiffResult diffResult) {
// ❌❌❌❌❌❌ Next Line is Crashing the app ❌❌❌❌❌
pendingUpdates.remove();
dispatchUpdates(newItems, diffResult);
if (pendingUpdates.size() > 0) {
updateItemsInternal(pendingUpdates.peek());
}
}
}
Observing LiveData
public void setUpAppliancesListLiveData()
{
if (applianceObserver!=null)
{
applianceObserver = null;
}
Log.e("Appliance Fetch","RoomName:"+this.roomName);
applianceObserver = new Observer<List<Appliance>>() {
#Override
public void onChanged(#Nullable List<Appliance> applianceEntities) {
// Log.e("Appliance Result","Appliance List \n\n:"+applianceEntities.toString());
new Thread(new Runnable() {
#Override
public void run() {
List<Appliance> applianceListTemp = applianceEntities;
zmoteRemoteList = new ArrayList<>(); //appDelegate.getDatabase().zmoteRemoteDao().getRemoteList(roomName);
// Sort according to name
Collections.sort(applianceListTemp, new Comparator<Appliance>() {
#Override
public int compare(Appliance item, Appliance t1) {
String s1 = item.getSwitchName();
String s2 = t1.getSwitchName();
return s1.compareToIgnoreCase(s2);
}
});
if(getActivity()!=null) {
getActivity().runOnUiThread(new Runnable() {
#Override
public void run() {
applianceList = applianceListTemp;
mRecyclerView.getRecycledViewPool().clear();
adapter.setApplianceList(applianceList,zmoteRemoteList);
}
});
}
}
}).start();
}
};
appDelegate.getDatabase().applianceDao().getApplinaceListByRoomName(this.roomName).observe(this, applianceObserver);
}

Volley library throws application exception

I am adding my two separate android activities in one application, one of my activity having volley library but it gives me an exception that appcontroller(volley library) its an application not an activity please help me out
Ya, you have mention in your manifest file appcontroller class as Application. This solves the exception.
Main Acitivity:
public class MainActivity extends FragmentActivity implements OnTabChangeListener, OnPageChangeListener {
MyPageAdapter pageAdapter;
private ViewPager mViewPager;
private TabHost mTabHost;
private Button btn;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mViewPager = (ViewPager) findViewById(R.id.viewpager);
// Tab Initialization
initialiseTabHost();
// Fragments and ViewPager Initialization
List<Fragment> fragments = getFragments();
pageAdapter = new MyPageAdapter(getSupportFragmentManager(), fragments);
mViewPager.setAdapter(pageAdapter);
mViewPager.setOnPageChangeListener(MainActivity.this);
}
// Method to add a TabHost
private static void AddTab(MainActivity activity, TabHost tabHost, TabHost.TabSpec tabSpec,String message,int picture,Context x)
{
tabSpec.setContent(new MyTabFactory(activity));
View tabIndicator = LayoutInflater.from(x).inflate(R.layout.tab_indicator, tabHost.getTabWidget(), false);
TextView title = (TextView) tabIndicator.findViewById(R.id.title);
title.setText(message);
ImageView icon = (ImageView) tabIndicator.findViewById(R.id.icon);
icon.setBackgroundDrawable(x.getResources().getDrawable(picture));
icon.setScaleType(ImageView.ScaleType.FIT_CENTER);
tabSpec.setIndicator(tabIndicator);
tabHost.addTab(tabSpec);
}
// Manages the Tab changes, synchronizing it with Pages
public void onTabChanged(String tag) {
int pos = this.mTabHost.getCurrentTab();
this.mViewPager.setCurrentItem(pos);
for(int i=0;i<mTabHost.getTabWidget().getChildCount();i++)
{
mTabHost.getTabWidget().getChildAt(i).setBackgroundColor(Color.BLUE);
//mTabHost.getTabWidget().setDividerDrawable(R.Color.transperant);
}
mTabHost.getTabWidget().getChildAt(mTabHost.getCurrentTab()).setBackgroundColor(Color.CYAN);// selected
}
#Override
public void onPageScrollStateChanged(int arg0) {
}
public void destroyItem(View collection, int position, Object view){
((ViewPager) collection).removeView((ImageView) view);
}
// Manages the Page changes, synchronizing it with Tabs
#Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
int pos = this.mViewPager.getCurrentItem();
this.mTabHost.setCurrentTab(pos);
}
#Override
public void onPageSelected(int arg0) {
}
private List<Fragment> getFragments(){
List<Fragment> fList = new ArrayList<Fragment>();
// TODO Put here your Fragments
NewSampleFragment f1 = NewSampleFragment.newInstance(getApplicationContext(),R.layout.newfragment_a);
MySampleFragment f2 = MySampleFragment.newInstance("Sample Fragment 2");
MySampleFragment f3 = MySampleFragment.newInstance("Sample Fragment 3");
MySampleFragment f4 = MySampleFragment.newInstance("Sample Fragment 4");
MySampleFragment f5 = MySampleFragment.newInstance("Sample Fragment 5");
fList.add(f1);
fList.add(f2);
fList.add(f3);
fList.add(f4);
fList.add(f5);
return fList;
}
// Tabs Creation
private void initialiseTabHost() {
mTabHost = (TabHost) findViewById(android.R.id.tabhost);
mTabHost.setup();
// TODO Put here your Tabs
MainActivity.AddTab(this, this.mTabHost, this.mTabHost.newTabSpec("Tab1").setIndicator("Tab1"),"Grocery",R.drawable.movies,getApplicationContext());
MainActivity.AddTab(this, this.mTabHost, this.mTabHost.newTabSpec("Tab2").setIndicator("Tab2"),"Crockery",R.drawable.artist,getApplicationContext());
MainActivity.AddTab(this, this.mTabHost, this.mTabHost.newTabSpec("Tab3").setIndicator("Tab3"),"Foods",R.drawable.song,getApplicationContext());
MainActivity.AddTab(this, this.mTabHost, this.mTabHost.newTabSpec("Tab3").setIndicator("Tab4"),"Drinks",R.drawable.shopping,getApplicationContext());
MainActivity.AddTab(this, this.mTabHost, this.mTabHost.newTabSpec("Tab3").setIndicator("Tab5"),"Toys",R.drawable.play,getApplicationContext());
mTabHost.setOnTabChangedListener(this);
}
}
OfferActivity (This should be open when button pressed)
public class OfferActivity extends Activity
{
private static final String TAG = MainActivity.class.getSimpleName();
private ListView listView;
private FeedListAdapter listAdapter;
private List<FeedItem> feedItems;
private ProgressDialog pDialog;
private String URL_FEED = "http://nusdtech.com/public_html/checking2.php";
#SuppressLint("NewApi")
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main1);
listView = (ListView) findViewById(R.id.list);
feedItems = new ArrayList<FeedItem>();
listAdapter = new FeedListAdapter(this, feedItems);
listView.setAdapter(listAdapter);
pDialog = new ProgressDialog(this);
// Showing progress dialog before making http request
pDialog.setMessage("Loading...");
pDialog.show();
// These two lines not needed,
// just to get the look of facebook (changing background color & hiding the icon)
getActionBar().setBackgroundDrawable(new ColorDrawable(Color.parseColor("#3b5998")));
//getActionBar().setIcon(
// new ColorDrawable(getResources().getColor(android.R.color.transparent)));
JsonArrayRequest movieReq = new JsonArrayRequest(URL_FEED,
new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
Log.d(TAG, response.toString());
hidePDialog();
// Parsing json
for (int i = 0; i < response.length(); i++) {
try {
JSONObject obj = response.getJSONObject(i);
FeedItem movie = new FeedItem();
movie.setId(obj.getInt("id"));
movie.setName(obj.getString("name"));
// Image might be null sometimes
String image = obj.isNull("image") ? null : obj
.getString("image");
movie.setImge(image);
movie.setStatus(obj.getString("status"));
movie.setProfilePic(obj.getString("profilePic"));
//movie.setTimeStamp(obj.getString("price"));
movie.setPrice(obj.getString("price"));
movie.setDate(obj.getString("dates"));
feedItems.add(movie);
} catch (JSONException e) {
e.printStackTrace();
}
}
// notifying list adapter about data changes
// so that it renders the list view with updated data
listAdapter.notifyDataSetChanged();
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
hidePDialog();
}
});
// Adding request to request queue
AppController.getInstance().addToRequestQueue(movieReq);
}
#Override
public void onDestroy() {
super.onDestroy();
hidePDialog();
}
private void hidePDialog() {
if (pDialog != null) {
pDialog.dismiss();
pDialog = null;
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
AppController:
public class AppController extends Application {
public static final String TAG = AppController.class.getSimpleName();
private RequestQueue mRequestQueue;
private ImageLoader mImageLoader;
LruBitmapCache mLruBitmapCache;
private static AppController mInstance;
#Override
public void onCreate() {
super.onCreate();
mInstance = this;
}
public static synchronized AppController getInstance() {
return mInstance;
}
public RequestQueue getRequestQueue() {
if (mRequestQueue == null) {
mRequestQueue = Volley.newRequestQueue(getApplicationContext());
}
return mRequestQueue;
}
public ImageLoader getImageLoader() {
getRequestQueue();
if (mImageLoader == null) {
getLruBitmapCache();
mImageLoader = new ImageLoader(this.mRequestQueue, mLruBitmapCache);
}
return this.mImageLoader;
}
public LruBitmapCache getLruBitmapCache() {
if (mLruBitmapCache == null)
mLruBitmapCache = new LruBitmapCache();
return this.mLruBitmapCache;
}
public <T> void addToRequestQueue(Request<T> req, String tag) {
req.setTag(TextUtils.isEmpty(tag) ? TAG : tag);
getRequestQueue().add(req);
}
public <T> void addToRequestQueue(Request<T> req) {
req.setTag(TAG);
getRequestQueue().add(req);
}
public void cancelPendingRequests(Object tag) {
if (mRequestQueue != null) {
mRequestQueue.cancelAll(tag);
}
}
}
Activity that contain fragment buttons
public class NewSampleFragment extends Fragment {
private static View mView;
private Context con;
public static final NewSampleFragment newInstance(Context con,int layout) {
NewSampleFragment f = new NewSampleFragment();
con=con;
Bundle b = new Bundle();
b.putInt("mylayout",layout);
f.setArguments(b);
return f;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
int layout = getArguments().getInt("mylayout");
mView = inflater.inflate(R.layout.newfragment_a, container, false);
Button button = (Button) mView.findViewById(R.id.bactivity);
Button offer=(Button) mView.findViewById(R.id.aactivity);
button.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v)
{
Intent myIntent = new Intent(getActivity(), ListViewDemo.class);
//Optional parameters
getActivity().startActivity(myIntent);
Log.e("Error","Kashif");
}
});
offer.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v)
{
startApplication("uzair.sabir.app.OfferActivity");
}
});
return mView;
}
public void startApplication(String application_name){
try{
Intent intent = new Intent("android.intent.action.MAIN");
intent.addCategory("android.intent.category.LAUNCHER");
intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
List<ResolveInfo> resolveinfo_list = getActivity().getPackageManager().queryIntentActivities(intent, 0);
for(ResolveInfo info:resolveinfo_list){
if(info.activityInfo.packageName.equalsIgnoreCase(application_name)){
launchComponent("uzair.sabir.app", "OfferActivity");
break;
}
}
}
catch (ActivityNotFoundException e) {
Toast.makeText(getActivity(), "There was a problem loading the application: "+application_name,Toast.LENGTH_SHORT).show();
Log.e("Error",e.getMessage());
}
}
private void launchComponent(String packageName, String name){
Intent launch_intent = new Intent("android.intent.action.MAIN");
launch_intent.addCategory("android.intent.category.LAUNCHER");
launch_intent.setComponent(new ComponentName(packageName, name));
launch_intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
getActivity().startActivity(launch_intent);
}
}

GWT retrieve list from datastore via serviceimpl

Hi I'm trying to retrieve a linkedhashset from the Google datastore but nothing seems to happen. I want to display the results in a Grid using GWT on a page. I have put system.out.println() in all the classes to see where I go wrong but it only shows one and I don't recieve any errors. I use 6 classes 2 in the server package(ContactDAOJdo/ContactServiceImpl) and 4 in the client package(ContactService/ContactServiceAsync/ContactListDelegate/ContactListGui). I hope someone can explain why this isn't worken and point me in the right direction.
public class ContactDAOJdo implements ContactDAO {
#SuppressWarnings("unchecked")
#Override
public LinkedHashSet<Contact> listContacts() {
PersistenceManager pm = PmfSingleton.get().getPersistenceManager();
String query = "select from " + Contact.class.getName();
System.out.print("ContactDAOJdo: ");
return (LinkedHashSet<Contact>) pm.newQuery(query).execute();
}
}
public class ContactServiceImpl extends RemoteServiceServlet implements ContactService{
private static final long serialVersionUID = 1L;
private ContactDAO contactDAO = new ContactDAOJdo() {
#Override
public LinkedHashSet<Contact> listContacts() {
LinkedHashSet<Contact> contacts = contactDAO.listContacts();
System.out.println("service imp "+contacts);
return contacts;
}
}
#RemoteServiceRelativePath("contact")
public interface ContactService extends RemoteService {
LinkedHashSet<Contact> listContacts();
}
public interface ContactServiceAsync {
void listContacts(AsyncCallback<LinkedHashSet <Contact>> callback);
}
public class ListContactDelegate {
private ContactServiceAsync contactService = GWT.create(ContactService.class);
ListContactGUI gui;
void listContacts(){
contactService.listContacts(new AsyncCallback<LinkedHashSet<Contact>> () {
public void onFailure(Throwable caught) {
gui.service_eventListContactenFailed(caught);
System.out.println("delegate "+caught);
}
public void onSuccess(LinkedHashSet<Contact> result) {
gui.service_eventListRetrievedFromService(result);
System.out.println("delegate "+result);
}
});
}
}
public class ListContactGUI {
protected Grid contactlijst;
protected ListContactDelegate listContactService;
private Label status;
public void init() {
status = new Label();
contactlijst = new Grid();
contactlijst.setVisible(false);
status.setText("Contact list is being retrieved");
placeWidgets();
}
public void service_eventListRetrievedFromService(LinkedHashSet<Contact> result){
System.out.println("1 service eventListRetreivedFromService "+result);
status.setText("Retrieved contactlist list");
contactlijst.setVisible(true);
this.contactlijst.clear();
this.contactlijst.resizeRows(1 + result.size());
int row = 1;
this.contactlijst.setWidget(0, 0, new Label ("Voornaam"));
this.contactlijst.setWidget(0, 1, new Label ("Achternaam"));
for(Contact contact: result) {
this.contactlijst.setWidget(row, 0, new Label (contact.getVoornaam()));
this.contactlijst.setWidget(row, 1, new Label (contact.getVoornaam()));
row++;
System.out.println("voornaam: "+contact.getVoornaam());
}
System.out.println("2 service eventListRetreivedFromService "+result);
}
public void placeWidgets() {
System.out.println("placewidget inside listcontactgui" + contactlijst);
RootPanel.get("status").add(status);
RootPanel.get("contactlijst").add(contactlijst);
}
public void service_eventListContactenFailed(Throwable caught) {
status.setText("Unable to retrieve contact list from database.");
}
}
It could be the query returns a lazy list. Which means not all values are in the list at the moment the list is send to the client. I used a trick to just call size() on the list (not sure how I got to that solution, but seems to work):
public LinkedHashSet<Contact> listContacts() {
final PersistenceManager pm = PmfSingleton.get().getPersistenceManager();
try {
final LinkedHashSet<Contact> contacts =
(LinkedHashSet<Contact>) pm.newQuery(Contact.class).execute();
contacts.size(); // this triggers to get all values.
return contacts;
} finally {
pm.close();
}
}
But I'm not sure if this is the best practice...

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