I'm relatively new to java and android programming, and i wanted to get coordinates based on a point that i tapped on HERE maps. I really hoped you guys could help me out with this.
Edit :
This is the code that i tried to implement, however, it returned me with the error : Error:(354, 53) error: cannot find symbol variable PointF :
private void addDestination() {
image.setImageResource(R.drawable.marker);
GeoCoordinate endpoint = map.pixelToGeo(PointF);
MapMarker destination = new MapMarker(endpoint,image);
if (destination != null)
{
map.removeMapObject(destination);
}
else
{
map.addMapObject(destination);
}
}
PointF is a datatype, so calling "map.pixelToGeo(PointF)" doesn't make sense, you need to call it with concrete data.
In a short:
You need to listen for click events (or longpress, or whatever event you wanna handle), and you get PointF data that's reflecting the screen coordinates. Then you can convert the screen coordinates via pixelToGeo into geocoordinates that you can use to add mapmarker or whatever you wanna do with it on the map.
Some code to help you getting started:
Listening to click events on the map (to retrieve the PointF screencoordinates) are done via registering the gestureListener to your mapview. Means, after successfull mapengine init, you do something like that:
yourMapViewInstance.getMapGesture().addOnGestureListener(yourGestureHandlerImpementation, 10, true);
and in your gestureHandler implementation, you can override several events (click, longpress, etc.), so for example you can do for longpress the following:
private MapGesture.OnGestureListener yourGestureHandlerImpementation = new MapGesture.OnGestureListener.OnGestureListenerAdapter()
{
#Override
public boolean onLongPressEvent(PointF p) {
GeoCoordinate c = map.pixelToGeo(p);
// c is your geoccordinate on the map, where you clicked on the screen
// [...]
}
}
Related
I'm creating a media player in JavaFX. In one of my methods, I've created a way to search for metadata in a Media-file and then display it in ImageView. Works fine first time, but as soon as I want to call it again using another Media object, the image doesn't show up. I'm a bit confused and inexperienced, but I think that perhaps I need to reset/stop the listener before going to next object in line?
So my question is! How do you remove the listener when "image" has been found, what do you type to make it happen?
If you think that there's another reason why my image wont display the second time, please let me know as well.
Thanks on purpose.
private void displayAlbumCover (){
// Will start to show a blank CD
File file = new File("src/sample/images/blank_cd.jpeg");
Image image = new Image(file.toURI().toString());
albumCoverView.setImage(image);
// However if an album cover is found in the meta-data it will be displayed
ObservableMap<String,Object> meta_data=me.getMetadata();
meta_data.addListener((MapChangeListener<String, Object>) ch -> {
if(ch.wasAdded()){
String key=ch.getKey();
Object value=ch.getValueAdded();
switch(key){
case "image":
albumCoverView.setImage((Image)value);
break;
}
}
});
}
ObservableMap has removeListner method. You can keep the listener instance to variable and then remove it later.
private MapChangeListener<String, Object> listener;
private void displayAlbumCover (){
// ...
this.listener = //...
meta_data.addListener(listener);
}
private void removeListener() {
me.getMetadata().removeListener(this.listener);
}
https://docs.oracle.com/javase/8/javafx/api/javafx/collections/ObservableMap.html#removeListener-javafx.collections.MapChangeListener-
I'm currently using osmdroid to display current positioning.
Based on the following example i tried to optimize the system a little bit by not constructing the ItemizedOverlay<OverlayItem> and ArrayList<OverlayItem> each time my location is changed, but construct them only once in the constructor, and later on simply add points to my ArrayList variable.
Here's how it looks now:
private void InitializeMarkersOverlay() {
mOverlayItemArrayList = new ArrayList<OverlayItem>();
ItemizedOverlay<OverlayItem> locationOverlay =
new ItemizedIconOverlay<OverlayItem>(this, mOverlayItemArrayList, null);
mMapView.getOverlays().add(locationOverlay);
}
and when a new location arrives:
private void AddPointToOverlay(GeoPoint gPt, boolean bShouldClearList) {
OverlayItem overlayItem = new OverlayItem("", "", gPt);
Drawable markerDrawable = ContextCompat.getDrawable(this, R.drawable.pin);
overlayItem.setMarker(markerDrawable);
// first time initializer
if(bShouldClearList) {
mOverlayItemArrayList.clear();
}
mOverlayItemArrayList.add(overlayItem);
}
Since my mMapView already has a pointer to mOverlayItemArrayList i was hoping that my mapview's layer would be automatically notified regarding the change. but nothing actually happens. Only by recreating the objects, i get to see the pin.
Adding to the list does not work because ItemizedIconOverlay need to do some operations on addition. You can check source code for ItemizedIconOverlay.
You can see there is call to populate() in addItem method (and all other methods which are manipulating with items).
public boolean addItem(final Item item) {
final boolean result = mItemList.add(item);
populate();
return result;
}
But populate() is an implementation detail and is marked as protected so you cannot call it directly.
Correct solution would be:
Don't keep reference to the list but to ItemizedIconOverlay
instance.
Use mLocationOverlay.addItem(overlayItem)
You may need to call mapView.invalidate() after adding new point.
I got it working by accessing the overlay directly from the mapview object, not sure why exactly, as i was hoping mMapView.getOverlays() would hold a reference to the ItemizedIconOverlay and its itimized array
if(mMapView.getOverlays().size() > 0) {
((ItemizedIconOverlay<OverlayItem>)mMapView.getOverlays().get(0)).removeAllItems();
((ItemizedIconOverlay<OverlayItem>)mMapView.getOverlays().get(0)).addItem(overlayItem);
}
}
Having an issue with tables and updating a label! Here is the dilemma, I have a sell button in my game that is updating the player's coins whenever they sell an item, that part is working perfectly. The issue I am having is trying to get the coin value to update on the screen while there in this separate menu (see pic attached, coins in the top left). The problem is that the coin value is in another stage in another class. This is because I have different tables that pop up in the middle when I click the different buttons at the bottom. I have tried helper methods for going in and clearing that table and updating it and then sending me back to this item page but it is not working, I can post any code needed but this is more of a general question on how to update a label within a table in a stage.
Update: So to kinda sum up my question, I have a Screen and I have have three tables in it the bottom table the top left and the top right. Then I add the table to the stage in the middle when they press the inventory or shop button etc. What I am looking to do is to keep the item page open and simply just update the value of the Coin label, I know I can change the text using .setText(); Im just not sure how I can update that portion of the screen etc..
Update 2: If I just set the screen back to a new screen of this screen it updates the coin value but then I am not on the item page anymore which is not ideal.
Update 3: Thanks for the help so far guys, #John your answer is super helpful aswell. Im still not getting this working though here is a little bit of the code where the label is being handled.
playerCoinLabel = new Label(playerSave.getCoinsString(),skin,"defaultMiddle");
This is where it is getting added to the table.
tableLeft = new Table(skin);
stage.addActor(tableLeft);
tableLeft.setBounds(0,0, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
tableLeft.setFillParent(true);
tableLeft.top().left();
tableLeft.add(healthNonButton).size(84,80).left().padLeft(10).padTop(5);
tableLeft.add(playerHealthLabel).left().padLeft(15);
tableLeft.row();
tableLeft.add(levelNonButton).size(74,70).center().padLeft(10);
tableLeft.add(playerLevelLabel).left().padLeft(19);
tableLeft.row();
tableLeft.add(coinNonButton).size(74,70).center().padLeft(10);
tableLeft.add(this.playerCoinLabel).left().padLeft(15); //This line
tableLeft.row();
Then I have this method for updating my label using the setText like you guys were telling me about.
public void updatePlayerCoins() {
playerCoinLabel.setText(playerSave.getCoinsString());
}
and if I call this method anywhere, render() or where im setting the new coin value it is not updating/changing the label in the top left of my screen. I can post all the code to a github if I need to just posted the things involving the label. This is just a project im working on to increase my skill set so sorry if I sound amateur, it is because I am!
Thanks everyone!
It seems like you're asking two things- how do I update a label? and How do I structure my code? It's hard to tell what's going wrong with the former since we can't see your code, but #Tenfour04 is right- you want to retain a reference to the label somewhere and call setText() when you want to change the amount.
As far as structuring your code, I would suggest a simple OOP design and then evolve it like so:
First, we need an object to represent the player:
class Player {
private int coins; // Pretend there are getters / setters.
private int health;
private int level;
}
Now you probably have more than one way that you want to represent this player information, so we'll split the rendering code into a separate class or set of classes:
class StatWidget {
private Stage stage;
private Player player;
private Label lblCoins;
public StatWidget(Player player) { // Pseudo-code
this.player = player;
this.stage = new Stage();
Table tbl = new Table();
this.lblCoins = new Label(); // Notice we keep a reference to the label
tbl.add( this.coins );
}
public void update() {
lblCoins.setText(player.getCoins());
}
}
Now you can sync the UI with your player object's state simply by calling Player#update(). But when do you call it?
You could call update() in your render method. This is a little inefficient because you're updating the object whether it needs to be updated or not, but it's dead simple, and if you're only updating a few UI elements this way it probably doesn't matter. Personally, I'd stop here.
If you want to be more precise, you would only call update() when you actually make a change to the Player's coins. You can do this by finding the places in your code where you set the player's coins and add the update call like so:
player.setCoins( A_LOT_OF_MONEY );
statWidget.update();
Problem is this gets more cumbersome as you add more widgets- all your game logic now has to know about StatWidget and make calls to it. We could cut this dependency a little bit by using an event-driven architecture. Essentially, whenever player's state changes, it would send an event to interested parties notifying them of the change. You could use the pseudo-code below:
interface Publisher {
void subscribe(Subscriber subby);
void unsubscribe(Subscriber subby);
}
class Player implements Publisher {
private List<Subscriber> subscribers;
private int coins;
// ...
public void setCoins(int amount) {
this.coins = amount;
for(Subscriber subscriber : subscribers) subscriber.notify("COINS", amount);
}
public void subscribe(Subscriber subby) {
this.subscribers.add(subby);
}
public void unsubscribe(Subscriber subby) {
this.subscribers.remove(subby);
}
}
interface Subscriber {
void notify(String event, int qty);
void dispose();
}
class StatWidget implements Subscriber {
private Publisher player;
private Label label;
// ...
public StatWidget(Player player) {
this.player = player;
this.player.addSubscriber(this);
void notify(String event, int qty) {
if(event.equals("COINS")) label.setText(qty);
}
void dispose() {
this.player.unsubscribe(this);
}
}
The event system above could certainly be polished, and you could likely do clever things with generics (or use a library that has thought all this out for your), but hopefully it illustrates the concepts.
Intro to me and my application school project
Hi,
iam pretty new with android and for some school project iam building an application where users can configure regions to recieve alerts from. The app need also make it posible to recieve alerts around the current location of the app user.
The app gets its info from a xml feed and sorts the data by the configured regions. The workflow is 1. to get the alerts which are in the configured regions. 2. When gps alerts are enabled the app need to get the location and when it is known it needs to do the first step again but this time the gps region is included. (i need to optimize this proces LATER)
(questions bellow)
intro to my app and problem
I'm using a asynctask in my application to download some xml feed. When the asynctask is ready i need to call 3 places for do something with the result.
1 class saves the result in the local database (alertmanager)
2 fragments (in a tabview) needs to show the results (1 in a map an one in a listview)
Now i use weakreferences for giving the call back "references" to the asynctask. in the onPostExecute() i use theWeakReference.get().updateMethod(result); for updating the class/fragments.
The alertmanager (the class who needs to recieve the updates) also calls a gps manager in the same method where it calls the asynctask to get the gps location. When i comment out (in my case with a if) the line what calls the gps manager the weak reference of the alertmanager will go to null in the asynctask between the constructor (all references are filled) and the doInBackground (the alertmanager reference is null, the other 2 still filled) which results in a crashing app.
When i dont comment out the if the app works fine.....
Alertmanager information
This is the method in the alertmanager who calls the async task. The references are filled on this place.
public void GetAlerts(List<WeakReference<e_Alerts>> callbackReferences, Context context) {
//Update the alerts in the listview and mapview with the local alerts.
List<Alert> localAlerts = internalDc.GetAllAlerts();
try {
for (WeakReference<e_Alerts> callback : callbackReferences) {
callback.get().UpdateAlerts(localAlerts);
}
} catch (Exception e) {
Log.e("AlertManager", e.getMessage());
}
//If connected to the internet then update the local db and the views
if (isConnectingToInternet(context)) {
WeakReference<e_Alerts> wr = new WeakReference<e_Alerts>(this);
callbackReferences.add(wr);
// Update the alerts where no location is needed for so the user has a quick result
externalDc.getAlerts(callbackReferences, areaManager.GetActiveAreas(false));
// If gps region is enabled then find the phones location and update the alerts
if (areaManager.GetGpsArea().IsActive()) {
new GpsManager(this.context, this, callbackReferences);
}
}
}
The GpsManager extends the LocationListener:
public class GpsManager extends Service implements LocationListener {
The listener is implemented by the Alertmanager
// This method is caled by the GPS Manager when the GPS location is changed
#Override
public void OnLocationChanged(Location location, List<WeakReference<e_Alerts>> references) {Area gpsArea = areaManager.GetGpsArea();
gpsArea.SetLocation(location);
areaManager.SaveArea(gpsArea);
externalDc.getAlerts(references, areaManager.GetActiveAreas(true));
}
Asynctask information
This are the asynctask methods:
Asynctask constructor:
Here the list callbackReferences contains 3 weakrefrences and all of them are filled (2x fragment reference 1x alertmanager reference)
public At_allAlerts(List<WeakReference<e_Alerts>> callbackReferences, List<Area> areas) {
this.mCallbackReferences = callbackReferences;
this.mAreas = areas;
}
doInBackground code:
The XmlDownloader: Downloads an xml feed an parses the xml to objects with a library
The AlertConverter: converts the xml object to the object i use in my app
Both classes can work without the asynctask class and don't use the references.
#Override
protected String doInBackground(String... inputUrl) {
Log.i("At_allAlerts", "Asynctask for downloading and parsing mAlerts is started");
try {
//Downloads the alert XMLs from the internet and parses it to xmlAlerts
this.mAlerts = new XmlDownloader().DownloadAlerts(inputUrl);
// Filters the mXml mAlerts so only the mAlerts where the enduser is interessed in will remain
this.mAlerts = filterAlerts(this.mAlerts);
// Converts the remaining xmlAlerts to Alerts;
this.mResult = new AlertConverter().Convert(this.mAlerts);
}catch (Exception e) {
Log.e("At_allAlerts",e.getMessage());
}
return null;
}
The onPostExecute method:
When the programm comes in this method the this.references.get(2) reference (alertmanager reference) = null, the other 2 references are still filed
#Override
protected void onPostExecute(String xml){
for (WeakReference<e_Alerts> reference : activityWeakReferences)
{
reference.get().UpdateAlerts(this.result);
}
}
filterAlerts Method:
private List<Item> filterAlerts(List<Item> alerts) {
List<Item> filteredXmlAlerts = new ArrayList<>();
for (Item alert : alerts)
{
Location alertLocation = new Location("");
alertLocation.setLatitude(alert.getGeometries().get(0).getLocations().get(0).getLat());
alertLocation.setLongitude(alert.getGeometries().get(0).getLocations().get(0).getLng());
for(Area area : this.mAreas)
{
if (area.IsOrganization() && alert.getCountryCode().toLowerCase().equals(area.getOrganizationcode().toLowerCase())){
filteredXmlAlerts.add(alert);
break;
}
else if(!area.IsOrganization() && isAlertInRegion(alertLocation, area)) {
filteredXmlAlerts.add(alert);
break;
}
}
}
return filteredXmlAlerts;
}
My Question(s)
I think Weakreference are the right way for giving references to asynctask is this correct or do i need to give it as an other object? (class or object or whatever?).
Why goes my reference to null? and only one of the 3? and only when i dont use the gps location class? and how to solve this?
I read something about the garbage collector what can be the cause of this problem, is this true and when yes how can i solve this?
It would be fine when the answere are simple to understand since android is pretty new for me.
Hey all, I'm still relatively new to Java, and looking for a sanity check.
I've been studying this Java port of Cocos2D and noticed that the CCLayer class has built-in hooks to the Android native touch events. That's great, but what I'd really like is for objects like CCSprite to directly respond to touch events without having to listen for those events in the layer and iterate through all the children to find which ones happen to intersect the event's x/y coordinates. So I figured that this would be the perfect chance to test my understanding of how to set up some event handlers and make a subclass of CCSprite that actually listens for touches without needing to go through CCLayer to know about it. Furthermore, I wanted to be able to assign different behaviors to different CCSprite instances on an ad-hoc basis without explicitly subclassing further, much like Android Buttons don't need to be subclassed just to give them a handler for their touch events.
This is what I came up with on a first pass:
// My touch interface for all touchable CCNode objects.
package com.scriptocalypse.cocos2d;
public interface ITouchable {
boolean onCCTouchesBegan();
boolean onCCTouchesEnded();
boolean onCCTouchesMoved();
}
And now the class that uses the ITouchable interface for its callbacks...
public class CCTouchSprite extends CCSprite implements CCTouchDelegateProtocol {
protected ITouchable mTouchable;
public void setTouchable(ITouchable pTouchable){
mTouchable = pTouchable;
boolean enable = mTouchable != null;
this.setIsTouchEnabled(enable);
}
public void setIsTouchable(boolean pEnabled){
// code to enable and disable touches snipped...
}
/////
// And now implementing the CCTouchDelegateProtocol...
/////
public boolean ccTouchesBegan(MotionEvent event) {
Log.d("hi there", "touch me");
if(mTouchable != null){
mTouchable.onCCTouchesBegan();
}
return CCTouchDispatcher.kEventHandled; // TODO Auto-generated method stub
}
public boolean ccTouchesMoved(MotionEvent event) {
if(mTouchable != null){
mTouchable.onCCTouchesMoved();
}
return CCTouchDispatcher.kEventIgnored; // TODO Auto-generated method stub
}
public boolean ccTouchesEnded(MotionEvent event) {
Log.d("hi there", "not touch me");
if(mTouchable != null){
mTouchable.onCCTouchesEnded();
}
return CCTouchDispatcher.kEventIgnored; // TODO Auto-generated method stub
}
}
And finally, instantiate the class and implement the interface...
final CCTouchSprite sprite = new CCTouchSprite(tex);
sprite.setIsTouchEnabled(true);
sprite.setPosition(CGPoint.ccp(160,240));
sprite.setTouchable(new ITouchable(){
#Override
public boolean onCCTouchesBegan() {
Log.d("SWEET SUCCESS", "I got a touch through my interface!");
return true;
}
#Override
public boolean onCCTouchesEnded() {
Log.d("SWEET SUCCESS", "You stopped touching my interface!");
sprite.runAction(CCRotateBy.action(1, 360));
return false;
}
#Override
public boolean onCCTouchesMoved(){
Log.d("SWEET SUCCESS", "You moved the touch");
return false;
}
});
So all of this works. The subclass does successfully register with the Cocos2D touch dispatcher, which successfully calls those ccTouches functions and pass them MotionEvents, which in turn call my Interface functions if the interface has been instantiated.
Is this the "proper" way to do it (Define "it" as you see fit, ranging from using Interfaces to create event handlers to working with Cocos2D, to writing Java at all)? Are there drawbacks to this that I'm not aware of? Is this somehow worse for performance than iterating through all the CCNode objects that are children of CCLayer? If so, how can that possibly be?
I think you have got the basics for setting up a listener right. There are some things I would change though.
First, the setter setIsTouchable. It's weird. You need a listener object to pass touch events to right? So what is this setter going to do when you pass it true (as your example does)? You snipped the code, but setting a boolean field to true does not seem right here as it would put the sprite object in an inconsistent internal state. I would just drop that setter. The getter can just evaluate whether mTouchable is assigned or null.
Second, why limit yourself to one listener? Change mTouchable to mTouchables, being a list of ITouchables. Then change setTouchable to addTouchable and possibly add removeTouchable and clearTouchables methods. This way you can add multiple listeners for different behaviors having to respond to the same events. This is how most other event systems work as well. You then just change isTouchable to check whether the list is empty or not.
scriptoclypse... I really am not completely understanding your question, but you have not had any response and yes interfaces and events are very similar. At this level I can only respond in C#.