I work on an application that using PhoneGap. For the moment, I only test it on Android. I have several pages in my application that need the geolocation feature.
So I made a JS to handle it with this line of code (of course it's not my unique line of code) :
navigator.geolocation.watchPosition(successGeolocation, errorGeolocation, {maximumAge: 5000, enableHighAccuracy: true});
The geolocation need to be the most accurate possible so I use the GPS and it can take some time to have a GPS Fix.
The problem is when the user navigates from one page to another. The WatchPosition stop (it's normal because the user load an other page) and when I recall it the GPS need to Fix again.
It's very annoying and I search a solution to keep the GPS active. Someone has an idea for me ? Maybe with a plugin or a native Android LoC I can keep it active during all the application life ?
Thanks.
First step you should create an Android plugin that will give you API for receiving the location data.
Creating a plugin is quite easy and is explained here:
Plugin Development Guide and Developing a Plugin on Android.
You can also see an example of creating a Cordova plugin here.
Next, create a location monitor class. You can make it singleton and initialize it from your main activity.
Here is a simple, but working code I compiled from several sources and many tests to fit my needs.
The main code is taken from here, though I simplified it as much as was possible.
public class LocationMonitor
{
private LocationListener locationListener = null;
private LocationManager locationManager = null;
private Location location = null;
public LocationMonitor()
{
}
public void startGPSActivity(Context context)
{
LocationLooper looper = new LocationLooper();
looper.start();
while (!looper.isReady())
{
}
looper.handler.post(new LocationBootstrapper(context));
}
public void stopGPSActivity()
{
locationManager.removeUpdates(locationListener);
}
public Location getLocation()
{
return location;
}
private class LocationLooper extends Thread
{
private Handler handler;
private LocationLooper()
{
}
public void run()
{
Looper.prepare();
this.handler = new Handler();
Looper.loop();
}
public boolean isReady()
{
return this.handler != null;
}
}
private class LocationBootstrapper implements Runnable
{
private Context context;
private LocationBootstrapper(Context context)
{
this.context = context;
}
public void run()
{
locationListener = new LocationListenerImpl();
locationManager = (LocationManager)context.getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 1, locationListener);
}
}
private class LocationListenerImpl implements LocationListener
{
private LocationListenerImpl()
{
}
#Override
public void onLocationChanged(Location location)
{
LocationMonitor.this.location = location;
Log.i("LocationMonitor", "New location: lat= " + location.getLatitude() + " lng=" + location.getLongitude() + " acc=" + location.getAccuracy());
}
#Override
public void onProviderDisabled(String provider)
{
}
#Override
public void onProviderEnabled(String provider)
{
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras)
{
}
}
}
Now access the LocationMonitor class from your plugin and you have your desired solution - page changes will not re-initialize your GPS and location data is available to your PhoneGap app.
Cheers
Related
I've been following the documentation for the webview2 on microsoft's official website but I have encountered a problem that I am not sure how to fix.
I have added a .NET object using AddHostObjectToScript and it works as long as the function has no parameter. When calling the object function that has a parameter in JS, I keep on getting a "parameter is incorrect" error.
This is how I am calling the host objects in angular app:
result = await window?.chrome?.webview?.hostObjects.bridge.Func("John");
and this is from my WinUI 3.0 app:
[ComVisible(true)]
public class Bridge
{
public string Func(string param)
{
return "Example: " + param;
}
public string Sample()
{
return "Example: ";
}
public BridgeAnotherClass AnotherObject { get; set; } = new BridgeAnotherClass();
// Sample indexed property.
[System.Runtime.CompilerServices.IndexerName("Items")]
public string this[int index]
{
get { return m_dictionary[index]; }
set { m_dictionary[index] = value; }
}
private Dictionary<int, string> m_dictionary = new Dictionary<int, string>();
}
public sealed partial class WebViewPage : Page
{
public WebViewViewModel ViewModel { get; }
public WebViewPage()
{
ViewModel = Ioc.Default.GetService<WebViewViewModel>();
InitializeComponent();
ViewModel.WebViewService.Initialize(webView);
webView.WebMessageReceived += getMsg;
InitializeAsync();
}
async void InitializeAsync()
{
await webView.EnsureCoreWebView2Async();
var interop = webView.CoreWebView2.As<ICoreWebView2Interop>();
interop.AddHostObjectToScript("bridge", new Bridge());
}
WebView2 currently has an issue where the WinRT API's interop interface AddHostObjectToScript doesn't work well with .NET objects. This is a bug in WebView2.
I want to implement a mechanism in a custom webview client (without JavaScript injection) that can block ads. Is a way I can catch ads and replace them with other ads from a trusted source?
Thanks
In your custom WebViewClient, you can override the function shouldInterceptRequest(WebView, WebResourceRequest).
From Android docs:
Notify the host application of a resource request and allow the application to return the data.
So the general idea is to check if the request is coming from an ad URL (plenty of black list filters out there), then return a "fake" resource that isn't the ad.
For a more in depth explanation plus an example, I recommend checking out this blog post.
To implement this, you have two options:
Use Javascript injected code to do this (which you explicitely said, don't want)
In WebView, instead of "http://example.com" load "http://myproxy.com?t=http://example.com" (properly escaped, of course) and setup "myproxy.com" to be a proxy which will fetch the upstream page (given in "t" query parameter, or in any other way) and replace ads with the trusted ones before sending response to the client. This will be pretty complex, though, because ads can be in many forms, they're usually Javascript injected themselves and you'd probably need to rewrite a lot of URL's in the fetched HTML, CSS and JS files etc.
I made a custom WebViewClient like:
public class MyWebViewClient extends WebViewClient {
#Override
public void onPageFinished(WebView view, String url) { }
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
if (url.endsWith(".mp4")) {
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.parse(url), "video/*");
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
view.getContext().startActivity(intent);
return true;
} else if (url.startsWith("tel:") || url.startsWith("sms:") || url.startsWith("smsto:")
|| url.startsWith("mms:") || url.startsWith("mmsto:")) {
Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
view.getContext().startActivity(intent);
return true;
} else {
return super.shouldOverrideUrlLoading(view, url);
}
}
private Map<String, Boolean> loadedUrls = new HashMap<>();
#SuppressWarnings("deprecation")
#Override
public WebResourceResponse shouldInterceptRequest(WebView view, String url) {
boolean ad;
if (!loadedUrls.containsKey(url)) {
ad = AdBlocker.isAd(url);
loadedUrls.put(url, ad);
} else {
ad = loadedUrls.get(url);
}
return ad ? AdBlocker.createEmptyResource() :
super.shouldInterceptRequest(view, url);
}
}
And created an AdBlocker class like:
public class AdBlocker {
private static final Set<String> AD_HOSTS = new HashSet<>();
public static boolean isAd(String url) {
try {
return isAdHost(getHost(url));
} catch (MalformedURLException e) {
Log.e("Devangi..", e.toString());
return false;
}
}
private static boolean isAdHost(String host) {
if (TextUtils.isEmpty(host)) {
return false;
}
int index = host.indexOf(".");
return index >= 0 && (AD_HOSTS.contains(host) ||
index + 1 < host.length() && isAdHost(host.substring(index + 1)));
}
public static WebResourceResponse createEmptyResource() {
return new WebResourceResponse("text/plain", "utf-8", new ByteArrayInputStream("".getBytes()));
}
public static String getHost(String url) throws MalformedURLException {
return new URL(url).getHost();
}
}
And use this WebViewClient in your oncreate like:
webview.setWebViewClient(new MyWebViewClient());
I use WebView to show data, the data gets augmented via JS function. It works fine until the device gets rotated. Using ViewModel to keep the page data and restore it after a config change seemed to be the right idea but I ran into problems, the page didn't get restored. I pared down my code to a minimalist example, included here (sans the XML layout)
DataStore class to store the data, overriding ViewModel, simply store some strings in a list
package com.automationce.labyrinth.webview;
import android.arch.lifecycle.ViewModel;
import java.util.ArrayList;
import java.util.List;
/* The idea is to use ViewModel to store page data
* so it can be restored on device rotate/split view */
public final class DataStore extends ViewModel {
public List<String> records = new ArrayList<>();
public DataStore() {
super();
}
}
Simple web view class, overriding WebView
package com.automationce.labyrinth.webview;
import android.content.Context;
import android.graphics.Color;
import android.util.AttributeSet;
import android.webkit.WebView;
public final class SimpleWebView extends WebView {
// Use to keep and restore data between config changes
// (not related to browser history by any means)
private DataStore dataStore;
public SimpleWebView(Context context, AttributeSet attrs) {
super(context, attrs);
setBackgroundColor(Color.LTGRAY);
getSettings().setJavaScriptEnabled(true);
setWebContentsDebuggingEnabled(true);
// Define style, write JS function(s)
String content = "<!DOCTYPE html><html><head>" +
"<style>" +
"span { font-size: " +
0.875 +
"em; } " +
"</style>" +
"</head><body id=\"body\">" +
jsFunctions() + "</body></html>";
loadDataWithBaseURL(null, content, "text/html", "utf-8", null);
}
// JS function(s) as written to the page
private String jsFunctions() {
return "<script>" +
"function append (string) { " +
"var body = document.getElementById('body');" +
"var block = document.createElement('span');" +
"var text = document.createTextNode(string);" +
"var br = document.createElement('br'); " +
"block.appendChild(text);" +
"block.appendChild(br); " +
"body.appendChild(block);" +
"block.scrollIntoView();" +
" }" +
"</script>";
}
public void setHistory (final DataStore storedData) {
dataStore = storedData;
}
// Restore page from DataStore data
public void restore() {
for(String record : dataStore.records) {
evaluateJavascript("append ('" + record + "');", null);
}
}
// Append new data to existing page
public void append(final String string) {
dataStore.records.add(string);
evaluateJavascript("append ('" + string + "');", null);
}
}
And finally the MainActivity itself
package com.automationce.labyrinth.webview;
import android.arch.lifecycle.ViewModelProviders;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
private SimpleWebView pageView;
private Button appendButton;
private int counter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DataStore storedData = ViewModelProviders.of(this).get(DataStore.class);
appendButton = findViewById(R.id.button);
pageView = findViewById(R.id.webView);
pageView.setHistory(storedData);
pageView.restore();
appendButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
append();
}
});
}
private void append() {
counter++;
pageView.append("Some kind of new text " + counter);
}
}
The idea was to preserve the data in ViewModel and restore it during creation. It took me a while to figure why it doesn't work. DataStore does get preserved during rotation (I can see all the history data in the DataStore object) but although I see the restore code being executed, it never gets rendered in SimpleWebView.
The reason is that while JavaScript function does get correctly written to the page, I am calling restore() from MainActivity.OnCreate before the page actually renders. The JS function gets called and quickly ignored because the page, in reality, doesn't exist as far as WebView is concerned (I think). Surprisingly, this actually worked on the majority of simulators I use - now I think it shouldn't and I have no clue why it did - until I ran it on a physical device (Galaxy S7), where the restore was ignored
My solution was to give my SimpleWebView a new WebViewClient and override its OnPageFinished method and in it restore the content of the page after the page finishes loading. SimpleView constructor ('firstView' boolean flag in the code below gets invalidated after the view reloads for the first time after the device rotation):
public SimpleWebView(Context context, AttributeSet attrs) {
super(context, attrs);
setBackgroundColor(Color.LTGRAY);
getSettings().setJavaScriptEnabled(true);
setWebContentsDebuggingEnabled(true);
setWebViewClient(new WebViewClient() {
#Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
Log.v("PAGE", "finished");
if (firstView) {
((SimpleWebView)view).restore();
}
}
});
.
.
The web page now gets reconstructed from the persistent data after device rotation/split window. It seems to work well, without any noticeable load delay (I am dealing with relatively small data set now).
I have looked for solutions, I really don't want to save and restore a String content of the whole page in OnSaveInstanceState / onRestoreInstanceState because in this case, it won't do me any good - I'll have the data but I still need to restore it after the page gets rendered
Words of wise I seek from the collective:
Is my analysis correct?
Are there better ways of handling this?
Is there something (an unpleasant production code surprise, etc. - I am pretty new to Android) for which I should be watching out?
Thanks, Jiri
I have some ajax Behaviour that should pick some data using JS, and turn it back to Java. Sometimes it works but quite ofen it is just add url parameter and do page refresing/
public abstract class LoggedVKIdBehaviour extends AbstractDefaultAjaxBehavior {
private static final Logger logger = LoggerFactory.getLogger(LoggedVKIdBehaviour.class);
#Override
protected void respond(AjaxRequestTarget target) {
String loggedVkId = RequestCycle.get().getRequest().getRequestParameters().getParameterValue("logged_vkid").toString();
logger.info("ajax has comming with logged VK ID " + loggedVkId);
recived(target, loggedVkId);
}
protected abstract void recived(AjaxRequestTarget target, String loggedVkId);
#Override
public void renderHead(final Component component, IHeaderResponse response) {
super.renderHead(component, response);
Map<String, Object> map = new HashMap<>();
map.put("callbackFunction", getCallbackFunction(CallbackParameter.explicit("logged_vkid")));
//
PackageTextTemplate ptt = new PackageTextTemplate(LoggedVKIdBehaviour.class, "vkid_callback.js");
OnDomReadyHeaderItem onDomReadyHeaderItem = OnDomReadyHeaderItem.forScript(ptt.asString(map));
response.render(onDomReadyHeaderItem);
}
}
js template
var calback = ${callbackFunction};
var logged_vk_id = 11;
function authInfo(response) {
if (response.session) {
logged_vk_id = response.session.mid;
calback(response.session.mid);
console.log("recived callback from VK " + logged_vk_id);
}
}
$(document).ready(function () {
VK.Auth.getLoginStatus(authInfo);
});
it is do recursive redirection like http://localhost:8080/mytool/product/1?logged_vkid=332797331&logged_vkid=332797331&logged_vkid=332797331&logged_vkid=332797331&logged_vkid=332773...
As i understand Ajaj technology - iti asynchronus requests, that shouldn't touch main url at all. So what is the reason for page refreshing?
this is generated Callback function
function (logged_vkid) {
var attrs = {"u":"../wicket/bookmarkable/com.tac.kulik.pages.product.ProductPage?12-1.IBehaviorListener.0-&productID=1"};
var params = [{"name":"logged_vkid","value":logged_vkid}];
attrs.ep = params.concat(attrs.ep || []);
Wicket.Ajax.ajax(attrs);
}
I use wicket 7.2
I did a lot investigations for few days. And found that when i remove
setPageManagerProvider(new NoSerializationPageManagerProvider(this));
Application throw me exepton in polite logs
org.apache.wicket.WicketRuntimeException: A problem occurred while
trying to collect debug information about not serializable object look
like it is could come from aused by: java.io.NotSerializableException:
com.tac.kulik.panel.smaccounts.SMAccountsPanel$1
which means that page tryed to be serialized for SOME REASON but $1 it is mean Anonimous class. I had few class created anonimously to ges some ajax links coming from ListView to be managed on parent panel. So After removing this Anonimous class logic, everything start and run well.
So i am happy, but still don't understand which reason page did serialization after ajax, and what the reason was to refresh whole page.
Recently I have encounter a problem with the web application. I'm using the spring mvc restful application together with hibernate as jpa.
The client could build a xml file using this format:
<SCCF>
<registerSCCF>...</registerSCCF>
...
<registerSCCF>...</registerSCCF>
</SCCF>
The web app will then mapping every data inside registerSCCF tag to a class and save it in the database.
Now I am suffering with the problem that when i test it using soapui and multithreading test, i always get the exception
[ERROR] an assertion failure occured (this may indicate a bug in Hibernate, but is more likely due to unsafe use of the session)
org.hibernate.AssertionFailure: null id in draft.persistence.entity.dcrm.CustomersNoneSSO entry (don't flush the Session after an exception occurs)
or
Caused by: org.hibernate.HibernateException: Flush during cascade is dangerous
or
org.hibernate.SessionException: Session is closed!
Here is the service layer code:
#Transactional("dcrm")
public boolean postSCCFService(SCCFVO sccf){
CustomersNoneSSO cns = new CustomersNoneSSO();
cns.setAppid(sccf.getAppid());
cns.setCustomer_name(sccf.getCustomer_name());
cns.setCustomer_gender(sccf.getCustomer_gender());
cns.setContact_mobile(sccf.getContact_mobile());
cns.setContact_email(sccf.getContact_email());
cns.setAddress_province(sccf.getAddress_province());
cns.setAddress_city(sccf.getAddress_city());
cns.setCustomer_address(sccf.getCustomer_address());
cns.setCustomer_occupation(sccf.getCustomer_occupation());
cns.setPurchase_brand(sccf.getPurchase_brand());
cns.setPurchase_model(sccf.getPurchase_model());
cns.setPurchase_date(sccf.getPurchase_date());
cns.setPurchase_budget(sccf.getPurchase_budget());
cns.setOwncar_selected(sccf.getOwncar_selected());
cns.setOwncar_model(sccf.getOwncar_model());
cns.setTestdrive_permission(sccf.getTestdrive_permission());
cns.setMarketing_permission(sccf.getMarketing_permission());
Timestamp t = new Timestamp(new Date().getTime());
cns.setInsert_timestamp(t);
cns.setUpdate_timestamp(t);
cnsDao.makePersistent(cns);
}
if i set all the setter to static values like:
cns.setContact_email("test#test.test");
instead of using the value from the parameter, then the app runs well with the multithreading test.
There is the controller calls the service method:
#RequestMapping(value = "/test",method=RequestMethod.POST)
public #ResponseBody SCCFResponseList getPostResults(#RequestBody SCCFVOList sccf){
...
for(SCCFVO sccfvo : sccf.getSCCFVOList()){
...
boolean result = sccfservice.postSCCFService(sccfvo);
...
}
...
}
public class SCCFVOList {
And here is the request body class:
#XmlElement(name="registerSCCF")
public class SCCFVOList {
private Vector<SCCFVO> SCCFVOList = null;
public Vector<SCCFVO> getSCCFVOList(){
return SCCFVOList;
}
public void setSCCFVOList(Vector<SCCFVO> SCCFVOList){
this.SCCFVOList = SCCFVOList;
}
}
And here the dao
public class CNSDao extends GenericHibernateDAO<CustomersNoneSSO, Long> {}
public abstract class GenericHibernateDAO<T, ID extends Serializable>
implements GenericDAO<T, ID> {
private Class<T> persistentClass;
private Session session;
SessionFactory sessionFactory;
public void setSessionFactory(SessionFactory sessionFactory){
this.sessionFactory = sessionFactory;
}
public GenericHibernateDAO() {
this.persistentClass = (Class<T>) ((ParameterizedType) getClass()
.getGenericSuperclass()).getActualTypeArguments()[0];
}
#SuppressWarnings("unchecked")
public void setSession(Session s) {
this.session = s;
}
protected Session getSession() {
session = sessionFactory.getCurrentSession();
if (session == null)
throw new IllegalStateException(
"Session has not been set on DAO before usage");
return session;
}
public Class<T> getPersistentClass() {
return persistentClass;
}
#SuppressWarnings("unchecked")
public T makePersistent(T entity) {
getSession().saveOrUpdate(entity);
return entity;
}
public void makeTransient(T entity) {
getSession().delete(entity);
}
...
}
There should be something wrong either the controller method or the service method. Still no idea what was wrong.
Your dao is flawed.
Your dao is a singleton, there is only one. The Hibernate Session object isn't thread safe and shouldn't be used across threads.
You have 1 dao, 2 threads, Thread one gets instance X1 of a session, Thread two resets it to instance X2 now suddenly they share the same session, not to mention Thread 1 might even be operating on 2 different sessions.
As I mentioned in the comments NEVER store the Session in an instance variable. Remove it.
public abstract class GenericHibernateDAO<T, ID extends Serializable> implements GenericDAO<T, ID> {
private Class<T> persistentClass;
private SessionFactory sessionFactory;
public GenericHibernateDAO() {
this.persistentClass = (Class<T>) ((ParameterizedType) getClass().getGenericSuperclass()).getActualTypeArguments()[0];
}
public void setSessionFactory(SessionFactory sessionFactory){
this.sessionFactory = sessionFactory;
}
protected Session getSession() {
return sessionFactory.getCurrentSession();
}
Also I would suggest dropping this and instead use Spring Data JPA saves you the trouble of creating and maintaining your own generic dao. (You mention you use JPA, if the entities are annotated it should be quite easy to do).