I am currently developing a game for the Android OS. In it, the player can carry out activities. Each activity costs the player "energy". The players current energy value is stored in an sqlite table and displayed on the home screen(home.class). When the player carries out activities, the energy value will decrease. When the energy reaches zero, i want a countdown timer to reset the energy value to 10.
The way I have implemented it so far is as follows. At the top of the main screen that displays the users health/energy ratings I have displayed the CountDownTimer.
The timer works. However, when I click a button and go to a different activity..and then return to the Home screen, the timer has restarted. I know this is because the following code runs when I want to return to the home screen:
Intent i = new Intent(Crime.this, Home.class);
startActivity(i);
It starts a new Home.class because i want to update the values displayed in the Home screen after some activities have been carried out.
What is a better way to implement the CountDownTimer? Any help would be appreciated...thanks :)
store the time at which you want to reset the energy in the database (at least once you hit onPause) and update the remaining time with a ticking thread thing. That way you don't need to rely on timers to finish / restart since you can always recalculate the times based on e.g. the current system time
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I want to make a hider count down so that in application when a user clicks on a Button that button should not appear again before 3 days or 2 days ...
I am new to Android Please Help
Google For AlarmManager. https://developer.android.com/training/scheduling/alarms.html .
How to set an alarm to be hit after 48Hours or more.
Save current time in preference at the alarm setting time.
Receive Device Boot Up Events. Android BroadcastReceiver on startup - keep running when Activity is in Background . As if device gets switched off. You will loose your set alarm
On device boot up fetch the time from your preference when you had set the alarm.
Calculate the time left for alarm to hit and set alarm again.
48Hours - (CurrentTime - YourLastAlarmCreationTime)
Do whatever at the time alarm manager notifies your receiver that time is over.
This should be simple. Let me know if there is anything you want more to know. And don't think of any timer or thread of your app to do this for you.
In my LibGDX game for android, if the user backs out of the game (either by pressing the home button or switching to another application) LibGDX's built in pause() method is supposed to run. Now, this is fine, and it works fine as well. My problem is that if I back out of the game to do whatever, and then rejoin the game, it has restarted the app completely (kind of like if every time you exited and rejoined in the middle of a game of Pacman your score would be zero and all the dots would be back). For my screen switching, it is necessary that the game NOT restart every time the user exits, but simply enter the corresponding state to actually simulate the 'paused' game. How do I stop LibGDX/Android from killing the game altogether upon user exit, but simply pausing it?
The libGDX application lifecycle matches the lifecycle of the Android Activity as documented in the ApplicationListener interface so you should expect the same behavior. When you press the home button while in a libGDX game then the pause method will be called, which is the same as onPause in Android. The game will go to the background but will stay in memory. However this is not guaranteed and the OS might release the games memory for other applications, there really is no way to get around this. In the case when the game comes back to the foreground and the game restarts you'll need to load the games state from when it was paused.
I've written my own article on how to save and load the game state using Json in libGDX, maybe that will be useful to you.
You should use Asset Manager to prevent it, here a good tutorial :
http://code.google.com/p/libgdx/wiki/AssetManager
the official doc :
http://code.google.com/p/libgdx/wiki/AssetManager
Load all of your textures with assets manager
I have the same problem, but I found the solution by:
Disable option in Developer options called
- Don't keep activities (Destroy every activity as soon as the user leaves it)
In my app I use a camera, and I want to take a pictures. In my app is button (Photo). If I press it one times - all work perfect, but if I press button many times until camera take picture, my app hangs. How can I fix it?
In your onClickListener call Button.setEnabled() and set it to false.
Then set it to true when you've finished taking the photo.
Use a listener that disables the button on press (setEnalbed(false)), than start a countdown thread that re-enables it after some time, 200ms maybe, or whatever fits the best.
After second thoughts this might not be a really good idea.
There is a chance that the thread will not be scheduled to run, so if you exactly know the point when you can re-enable the button in your code, don't use threads.
I have an app which uses the ACTION_MEDIA_BUTTON intent with a BroadcastReceiver to control a music player. The user pushes a button on external hardware and it controls the in-app music player. The user can also HOLD DOWN the button and change the volume.
I recently downloaded another app which uses the headset button, and it takes over the media button intent from my app! So when this other app is open and I press the button, the other app will start running, but my app will think that the button is still pressed down so it will cycle the volume.
To summarize,
my app is open, supposed to be sole listener of media button intents
other app gets opened, it also wants to be sole listener of media button intents
button gets pressed with both apps open, control goes to other app
my app thinks the button is being held down, as it lost control as the button was pressed in down mode (I think). It then launches functions I don't want launched because it thinks the user has held down the button.
Is there any way I could make sure that while my app is open it's the sole receiver of this media button intent? Could I at least check to see if another app has taken over, so I can prevent unexpected behaviour?
Thank you for any help, I've never had apps not play nicely before!
You can alter your BroadcastReceiver's priority (make it something large, like 10000): it should then get the Intent first, and then you can pass it on to the other app.
I have a similiar issue. I believe, outside of the 'arms race' over the priorites mentioned, the only real solution is to close the other application. If you are releasing this application to other users, you could possibly give them a message telling them to close other media player apps and services.
In your manifest you can set the intent priority to the max value of an integer which is: 2147483647.
You should not however set your IntentFilter priority over 1000 as it tells you in the API docs. You can set the IntentFilter priority like so:
myIntentFilter.setPriority(IntentFilter.SYSTEM_HIGH_PRIORITY);
I assume you should subtract one from the SYSTEM_HIGH_PRIORITY constant as the docs say the value must be less than SYSTEM_HIGH_PRIORITY.
Quote from docs about IntentFilter.setPriority(int):
Applications must use a value that is larger than SYSTEM_LOW_PRIORITY and smaller than SYSTEM_HIGH_PRIORITY.
I'm making a game in Android and I'm trying to add a set of menu screens. Each screen takes up the whole display and has various transitions available to other screens. As a rough summary, the menu screens are:
Start screen
Difficult select screen
Game screen.
Pause screen.
Game over screen.
And there are several different ways you can transition between screen:
1 -> 2
2 -> 3
3 -> 4 (pause game)
4 -> 1 (exit game)
4 -> 3 (resume game)
3 -> 5 (game ends)
Obviously, I need some stored state when moving between screens, such as the difficulty level select when starting a game and what the player's score is when the game over screen is shown.
Can anyone give me some advice for the easiest way to implement the above screens and transitions in Android? All the create/destroy/pause/resume methods make me nervous about writing brittle code if I'm not careful.
I'm not fond of using an Activity for each screen. It seems too heavy weight, having to pass data around using intents seems like a real pain and each screen isn't a useful module by itself. As the "back" button doesn't always go back to the previous screen either, my menu layout doesn't seem to fit the activity model well.
At the moment, I'm representing each screen as an XML layout file and
I have one activity. I set the different buttons on each layout to call setContentView to update the screen the main activity is showing (e.g. the pause button changes the layout to the pause screen). The activity holds onto all the state needed (e.g. the current difficulty level and the game high score), which makes it easy to share data between screens. This seems roughly similar to the LunarLander sample, except I'm using multiple screens.
Does what I have at the moment sound OK or am I not doing things the typical Android way? Is there a class I can use (e.g. something like ViewFlipper) that could make my life easier?
By the way, my game screen is implemented as a SurfaceView that stores the game state. I need the state in this view to persist between calls to setContentView (e.g. to resume from paused). Is the right idea to create the game view when the activity starts, keep a reference to it and then use this reference with setContentView whenever I want the game screen to appear?
This question has been asked a lot. Did you read these other posts?
Android: What is better - multiple activities or switching views manually?. This link in particular talks about the Android Design Guidelines which "don't mention switching Views at all; it's centered around an Activity-as-View design."
Android - Should I use multiple activities or multiple content views
Android app with multiple activities
How to pass the values from one activity to previous activity
I'm not sure what you mean by the back button not always going back to the right screen correctly. I've got a game with a similar structure to yours, and the back button always takes the user correctly up the chain of activities.
Furthermore, using the onResume, onPause etc is somewhat necessary. What happens to your application if the phone rings? (Yes I know, some people still do strange things like using their phone to receive calls! :P) The OS tries to call the onPause method in your activity, but if that isn't implemented then your application won't act as expected. Another useful thing with onResume is it lets you update your tables as soon as the user returns to the view. For example, your player has just completed a level and is then brought back to the select difficulty screen. If you simply recover the previous screen from memory, it might not have been updated to take into account that a the level was just completed. However, if you put some code in onResume to handle that, then that will always be executed before the player sees the screen.
Lastly, you say transferring data around activities is a pain with intents - yes, that's probably true. But I usually find transferring any kind of complex data a pain, no matter how you do it. Are intents really that much worse, or is it just that things aren't as easy as you'd hoped? I don't mean any offense with that; I also often find things which intuitively seem easy to be rather frustrating to implement in code.