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[Q] Why cant I call a method from another class?

I have 2 classes in one .java file and it runs fine without errors or anything (the second class is used as a timer and changes variables every second) everything works but it wont call methods properly. Any idea of why this would be??? Heres my code of the second class.
Code:
class MyTime extends TimerTask{
//java.text.DateFormat format = SimpleDateFormat.getTimeInstance(SimpleDateFormat.MEDIUM, Locale.getDefault());
public game timecall2= new game();
public MyTime(Context ctx) {
// create internal instance
Context ctx2;
}
@Override
public void run() {
game.sec--;
if(game.sec==-1){game.sec=59;game.min--;}
game.Title2(); // set text in title bar
}
}

It would be easier if you explain more cleary, what you want to do.
Or post more code.
public game timecall2= new game();
I think, game is your first class?
Then you want to use the variable sec of the class game?
-> are they declared as static or why you don't call it over the object timecall2 you created?
Sry, but without more Code/Information to unterstand your problem, it's difficult to help. Also don't know, how skilled your are in programming.

*game* is the first class
I've tried calling the method through *timecall2* object but it doesn't help.
I've tried declaring the function as both static and no-static but nothing seems to change.
I've got lots of programming experience in other languages, but I'm less experienced with Java

And what's going wrong now?
Why don't you debug trough the code. Should be the easiest ways to find the problem.

You generally should use getters and setters for accessing variables inside of another class. Meaning that you have a method to set the value of the variable and a method to retrieve the value
Code:
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class MyClass extends Activity {
private static int mMin = 0;
private static int mSec = 0;
private TextView titleText;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
TextView titleText = (TextView) findViewById(R.id.titleText);
}
public static int getSec() {
return mSec;
}
public static void setSec(int newVal) {
mSec = newVal;
}
public static int getMin() {
return mMin;
}
public static void setMin(int newVal) {
mMin = newVal;
}
public static void setTitleText(String newVal) {
if (titleText != null) {
titleText.setText(newVal);
}
}
}
Notice the "static" modifier of the class methods.
Generally, you wouldn't instantiate this activity class. Especially if it already lives in memory. What I am guessing that you are doing here is that "game" is your activity and that MyTime is an object that you are using from inside of the activity and that you need to modify variables that live in the main Activity.
If that is the case then you would just do something like this:
Code:
import java.util.TimerTask;
import com.myapp.game.MyActivity;
class MyTime extends TimerTask {
private int sec = 0;
private int min = 0;
@Override
public void run() {
sec = MyActivity.getSec();
min = MyActivity.getMin();
sec--;
if(sec==-1) {
sec=59;
min--;
}
String title = String.valueOf(min)+":"+String.valueOf(sec); //obviously you need formatting
MyActivity.SetTitle(title); // set text in title bar
MyActivity.setSec(sec);
MyActivity.setMin(min);
}
}
That said... I just did the above as an example. This is entirely the wrong way to make a game timer. There is a better example here

From what I remember from C++, you would have a "base" class and then other classes beneath that base class.
To use the base class methods, the other classes had to be "friends". I'm a little rusty on my JAVA syntax...is "extends" the same thing as a friend class?

Java doesn't have friend functions, and "extends" means that the class is a subclass of whatever its extending.

To access a function/variable between classes that said function/variable must be static. Beware tho when do this depending on you implementation you must check for null variables. Since its static you can access you dont need a class object to access them through.
ak. SomeClass.function();
instead of using SomClass sc = new SomeClass(); sc.function();
since u can access it at any time its contents may not be initialized and be null. So ALWAYS check for null varaibles! lol. That or u can have one variable of that class to check if its class is initialized. such as..
SomeFunction.isInit();
where isInit(); is
private static initialized = false;
public static boolean isInit()
{
return initialized;
}
where in your onCreate & on onDestroy functions you set the initialized variable accordingly.
or..u could just do if(SomeClass.this!=null) lol :S
/me stops writting wot

Thanks for the input everyone. I've realised the problem (but still can't fix it). I can call methods in other classes from my timer class.... but my main class that has the methods that I need implements OnClickListener (public class game extends Activity implements OnClickListener) so it is ONLY updating the view methods when something is clicked on. How should I go about fixing it so that I can call methods that will update when a timer calls them (e.g. I display the remaining time in the title bar and it doesn't update the current time UNLESS a button is clicked on)

Why not run the timer as a thread in the activity class itself?

[Q] update view of activity that implements onClickListener without needing to click

How do you update an activity that implements on click listener WITHOUT needing to click something? (e.g. with a timer)

What is it you are trying to do? Why the new thread?

I need to update button, background images and text based on a timer instead of only updating when something is clicked

I don't understand what you mean by "only updating when something is clicked."

the images used (e.g. back ground, or buttons) will not change (update) unless a button is clicked. So its basically waiting for something to be pressed (any button) before it updates any imgaes

So let me get this straight; you're changing the images associated with layout controls in a timer of some kind? What kind of timer implementation? Is the timer in its own thread?

yeah. I tried making another class for the time but it doesn't work for updating the view of the main activity that I want. So I am trying to use:
Timer timer2 = new Timer();
timer2.scheduleAtFixedRate(Title(), 1, 1000);
Title() is defined as: public TimerTask Title()

NEVERMIND!! I GOT IT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
TimerTask scanTask;
final Handler handler = new Handler();
Timer t = new Timer();
scanTask = new TimerTask() {
public void run() {
handler.post(new Runnable() {
public void run() {
// stuff to do
}
});
}};
t.schedule(scanTask, 1, 1000);

Help writing something with setOnItemClickListener

In my Android app, I have a sound that I want to play when a certain selection has been made from a spinner, but I want it to play the when the user actually makes the proper selection (or just after). My problem is that although the sound does play when they make the correct selection, as long as that selection stays chosen, it also plays every time the app starts up, when it should ONLY play at the time it's chosen. I think I need to change my setOnItemSelectedListener to setOnItemClickListener, but I'm not sure how (still pretty new to java). Can any generous soul out there show me how to change this up (assuming that's how to best solve this problem)?
Here is the code I have now:
Code:
fitnessSpinner = (Spinner) findViewById(R.id.fitness_spinner);
ArrayAdapter adapter4 = ArrayAdapter.createFromResource(
this, R.array.fitness_array, android.R.layout.simple_spinner_item);
adapter4.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
fitnessSpinner.setAdapter(adapter4);
fitnessSpinner.setOnItemSelectedListener(new OnItemSelectedListener()
{
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long i) {
Log.d("test", "p: " + position + " " + i);
if(position == 0) {
//First Entry
MediaPlayer mp = MediaPlayer.create(mContext, R.raw.bowchica);
mp.start();
} if(position == 4) {
MediaPlayer mp = MediaPlayer.create(mContext, R.raw.debbie2);
mp.start();
}
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
}
});

I haven't try the below code but you can try it on your own and tell us.
In onCreate() declare MediaPlayer mp;
In every if statement that you use for check insert this code:
Code:
if(mp!=null){mp.release();}
int resid = R.raw.yoursound;
mp = MediaPlayer.create(this, resid);
After that override the methods onPause() and onResume() and insert this:
if(mp!=null){mp.release();}
If it is still playing a sound when you start your app, then you should check your code again if you have set as default option any of your selection options.

I would LOVE to try this out...Unfortunately, I'm way too dumb at this point point ot figure out exactly where those code snippets would go inside of what I already have.
Does anyone have a couple of minutes to show me where it would go?

Below is a sample code. Since i don't know your code I give you a snippet that you should adjust it to your code.
Code:
public class SampleSound extends Activity{
private Spinner fitnessSpinner;
private MediaPlayer mp;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);//here goes your layout
setViews();//here you will set all your views(spinners buttons textviews etc..)
setAdapters();//set your adapters here
setListeners();//
}
private void setListeners() {
fitnessSpinner.setOnItemSelectedListener(new OnItemSelectedListener(){
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long i) {
Log.d("test", "p: " + position + " " + i);
if(position == 0) {
//First Entry
if(mp!=null){mp.release();}
int resid = R.raw.bowchica;
mp = MediaPlayer.create(this, resid);
mp.start();
} if(position == 4) {
if(mp!=null){mp.release();}
int resid = R.raw.debbie2;
mp = MediaPlayer.create(this, resid);
mp.start();
}
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
}
});
}
private void setAdapters() {
ArrayAdapter adapter4 = ArrayAdapter.createFromResource(this, R.array.fitness_array, android.R.layout.simple_spinner_item);
adapter4.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
fitnessSpinner.setAdapter(adapter4);
}
private void setViews() {
fitnessSpinner = (Spinner) findViewById(R.id.fitness_spinner);
}
public void onResume(){
super.onResume();
if(mp!=null){mp.release();}
}
public void onPause(){
super.onPause();
if(mp!=null){mp.release();}
}
}

I really appreciate the help. I put the code in my routine, but it still plays the sound every time the activity is loaded (as long as the selection in the spinner is correct). It should only play the sound when the correct selection is made.
Any other ideas?

I am sure that your Spinner is set to some value (since you have values to display). Because your Spinner points to a selection (doesn't matter if you have selected or it is selected by default) your sound plays (even when you start the app).
A way to stop the sound playing at start is to declare and an other Item like you did with the previous 4 and set it as default selection of your Spinner.
To sum up:
1.You have to append in R.array.fitness_array an Item (like you did with the previous Items) and give it a name.
2.At the end of method setAdapters() insert this:
Code:
fitnessSpiner.setSelection(5);// or whatever is your selection number
Now it should work but you should know that this is not a good practice and you should try make a ListView or something else.

I'd be happy to change this out to a listview, or whatever would work. I just have to give my user a choice of 4 or 5 items, from which they can choose only one. Something like a drop down box, but in Android, I thought my only option was a spinner. But whatever I use, I have to be able to play a sound when certain items are chosen, but ONLY when those items are chosen, NOT whenever the activity is called up.
Any specific ideas of what I might change to?

What if I had another control like a textview or an edittext (with it's visibility property set to false) that I programatically populated with the users selection (when it's the selection that I want) and then have an OnItemClcickListener set to play the sound?
Could that work?

I will answer from the last to the top of your questions.
1.You can do whatever you want with android. You want TextViews and EditTexts with complex and nested Layouts you can do it. Write services that will communicate with your contacts through a content provider? You can do it.
Write, read and test code. Only this way you will actually learn.
2.Read developer.android.com. Read the android tutorials from there and specifically the Notepad example. You will learn a lot.
A good resource with small examples for ListViews is this.
3.Have you tried the changes I told you from the last post? Did it worked?
Since you just started with android and programming you must first be happy if you have the expected result and then read more to make your code better

Your suggested changes (fitnessSpiner.setSelection(5);// or whatever is your selection number) would stop the sound from playing, but defeat the apps purpose. Every time this activity is loaded, the spinners hit preferences to load the previously stored data. So if I force the spinner to a different selection to NOT play sound when the activity loads, then I would be displaying the wrong data for the user.

Yes you are right. So it is better to make a ListActivity. Read developer.android.com and the link i gave you before. You will be ok with this!

You're using "setOnItemSelectedListener", which sounds like when the app starts, its getting "selected" again.
Have you tried using "setOnItemClickListener" instead?
fitnessSpinner.setOnItemClickListener(new AdapterView.OnItemClickListener () {
public void onItemClicked() {}
};

Lakers16 said:
You're using "setOnItemSelectedListener", which sounds like when the app starts, its getting "selected" again.
Have you tried using "setOnItemClickListener" instead?
fitnessSpinner.setOnItemClickListener(new AdapterView.OnItemClickListener () {
public void onItemClicked() {}
};
Click to expand...
Click to collapse
onClickListener doesn't work for the spinner...I wish it did.
I REALLY need the drop down functionality of teh spinner, so I guess I'm going to try and figure out a way to have an invisible edittext that I set to the spinner selection and then use onClickListener or onChange...

Strange error while returning an Object value

I posted my problem at stackoverflow, please help me if you can.
my problem is very.. different. I got a code similar to:
Code:
public class PlayerCharacter
{
public void move(int direction)
{
if(direction != 0) //Skips this
{
...
}
else //Enter here
{
destinationMap = GamePlayScreen.canTransferMap(direction);
...
}
...
}
}
public Class GamePlayScreen
{
private PlayerCharacter p;
private static GamePlayScreen instance;
...
public void codeStartsHere()
{
//heppens in motionEvent only
p.move(0);
}
public static Map canTransferMap(int direction)
{
return instance.canTransferToMap(direction); //returns here the currect value
}
private Map canTransferToMap(int direction)
{
...
return getMap(nextMapName); //returns here the currect value
}
public Map getMap(String mapName)
{
for(Map t : maps)
{
if(t.getMapName().equals(mapName) == true)
{
return t; //returns here the currect value
}
}
return null; //never gets here
}
}
Everything works fine until "GamePlayScreen.canTransferMap(direction)" ends. Though it gets the correct value from "instance.canTransferToMap(direction)", when I watch PlayerCharacter->move->destinationMap I see that it returns a null!
I went step by step and watched the return values in every "return", before & after it: it returns null instead of the value! What is even stranger, it ALWAYS works at the first time and fails at the 2nd.
I updated the android SDK but didn't help, and so reinstalling the application & doing "project->clean".
Notes:
1. I'm using Galaxy S I9000, eclipse and it is a canvas drawn application.
2. I wrote as close a copy as I could (please note that this is my REAL code).
Thanks in advance

It's hard to tell for sure, but I think you've got a scope problem. You're assigning a value to destinationMap by calling a static function of the class GamePlayScreen, but the static function is calling non-static functions within the same class so unless maps is declared static, your for loop: for (Map t: maps) , is probably returning a local variable Map that is going out of scope as soon as your call return t.

It isn't a local array, it's "private ArrayList<Map> maps;" that is defined along side "private PlayerCharacter p;" and "private static GamePlayScreen instance;" in GamePlayScreen's instance;
I tired to replace the "for-each" loop with a regular "for" but it doesn't change anything.
Though a return of a non-existing object address may sound logical, it is not possible in Java because all of the objects are allocated in the heap and not in stack. (Though I had such problems in C++)

Well, I'd have to see all the code involved I guess. I know that all objects in Java are heap based, but that also means that they must be new'd somewhere too and I saw no new for the Map object, but I suppose you did that when you placed them in the ArrayList. The static qualifier on canTransferMap() throws me off though. Why is it there if you're returning a properly new'd object?

In my code I wish to access GamePlayScreen's data from within PlayerCharacter, even though I do not have the needed reference.
My solution for that is to have a static reference to GamePlayScreen in GamePlayScreen and thus it is available from everywhere. (And I know I will not have more then one GamePlayScreen at once in my game)
About the "new" keyword, as for now I have zero "new"-s while playing the game.
I pre-allocate ALL of my data and release the temporary in a loading screen, right before the actual game starts.

[Q] How to register a listener inside the AccessibilityService?

I'd like to register a listener inside AccessibilityService extented class but I don't know how to achieve that as I don't have a instance of it (it is started using intent). Or maybe there is another way of getting callback from this class? I just want to notify another class when the "onAccessibilityEven()" is trigerred.
Code:
public class NotifyService extends AccessibilityService {
// declaration of the interface
public interface Listener {
public void onNotifyChange(boolean newNotification);
}
// registration of the listener
public void registerListener(Listener listener) {
mListener = listener;
}
// ...
@Override
public void onAccessibilityEvent(AccessibilityEvent event) {
if(mListener != null) {
mListener.onNotifyChange(true);
}
}
}

Can you build an handler in the other class? If yes, just send a message and the handler in the other class will receive it If you need an example I will write it.

Do you mean the same handler which is usually used for communicating between threads? If you could give me some example would be great.