I'm trying to make a class called timer. The timer class is supposed to be called upon when my character enters the enemy's area. And the timer class is supposed to remove the characters health by 10-health points every 5 seconds. Ive tried multiple different timers but i cant seem to get any of them right. When i tried it removed health but it didn't do it only once, it kept repeating it until the health bar was out of the screen. here is my code:
class Timer {
g = new gubbe();
gubbe g;
Timer timer = new Timer(3000, new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
g.RemoveHealth();
}
});
timer.setRepeats(false);
timer.start();
}
That is what I've come up with so far.
If any more code is needed just ask.
Here's a class which you can use to time your events:
class Delay {
protected int limit;
public Delay() {limit = millis();}
public Delay (int l) {
limit = millis() + l;
}
public boolean expired () {
if (millis() > limit) { return true; }
return false;
}
}
To check on something every 5 seconds, you would have to initialize it like this:
Delay _delay;
void setup() {
_delay = new Delay(5000);
}
void draw() {
if (_delay.expired()) {
//do something
_delay = new Delay(5000);
}
}
The 5000 is in milliseconds, so it means 5 seconds. If you want to check for a 1 second delay, it would be 1000 instead. We re-initialize it when the delay is finished so it triggers again in 5 more seconds.
Have fun!
I'm creating 2 timers in my code. One is the logic timer that updates the logic every 0.017 seconds:
logicTimer = new Timer();
logicTimer.scheduleTask(new Timer.Task() {
#Override
public void run() {
updateLogic();
}
}, 0f, timePerProcessing);
And the other one is for generating obstacles every 3 seconds:
meteoroidTimer = new Timer();
meteoroidTimer.scheduleTask(new Timer.Task() {
#Override
public void run() {
generateMeteoroids();
}
},1f,3f);
When I pause my game and resume afterwards, my logic timer still works but my obstacle timer doesn't. I thought it was because I use a Random object in my method that I call in the timer, but I tried with a simple:
System.out.println("It is showing");
and it still doesn't resume.
My code for pause and resume:
#Override
public void pause(){
meteoroidTimer.stop();
logicTimer.stop();
}
#Override
public void resume(){
meteoroidTimer.start();
logicTimer.start();
}
You dont need to use the timer.stop and star on resume because when you leave the app libgdx stops rendering/updating anyway so your timers wont be updated anyway.
I am writing a script that will cause the players HP to decrease at an interval as long as they are within a range of the item/monster/lava whatever it is. I have the detection just fine, but I cant seem to get the interval to run. I know this is probably because I am creating a new TimerTask as I render, but I cant seem to figure it out.
for(Monster monster : monsters) {
renderer.processEntity(monster);
if(player.withinDistance(10, monster.getPosition()))
timer.scheduleAtFixedRate(new TimerTask() {
#Override
public void run() {
System.out.println("tick");
Player.PLAYER_HEALTH -= 10;
}
}, 2000, 2000);
}
So for all monsters, it checks the positions, if you are near it opens a timer task that should tick every 2 seconds while that condition is true. How can I make this work properly? Is a timer task optimal for this situation?
The problem here is that you are updating the PLAYER_HEALTH static property of the Player class. You should update the Player instance!
for(Monster monster : monsters) {
renderer.processEntity(monster);
if(player.withinDistance(10, monster.getPosition()))
timer.scheduleAtFixedRate(new TimerTask() {
#Override
public void run() {
System.out.println("tick");
player.decreaseHealth(10); // Use the instance
}
}, 2000, 2000);
}
Also, if your program ends, the TimerTask will end too. Make sure your program is still running.
I'm currently using a Timer and TimerTask to perform some work every 30 seconds.
My problem is that after each time I do this work I want to increment the interval time of the Timer.
So for example it starts off with 30 seconds between the timer firing but I want to add 10 seconds to the interval then so that the next time the Timer takes 40 seconds before it fires.
Here is my previous code:
public void StartScanning() {
scanTask = new TimerTask() {
public void run() {
handler.post(new Runnable() {
public void run() {
wifiManager.startScan();
scanCount++;
if(SCAN_INTERVAL_TIME <= SCAN_MAX_INTERVAL){
SCAN_INTERVAL_TIME = SCAN_INTERVAL_TIME + SCAN_INCREASE_INTERVAL;
t.schedule(scanTask, 0, SCAN_INTERVAL_TIME);
}
}
});
}};
Log.d("SCAN_INTERVAL_TIME ** ", "SCAN_INTERVAL_TIME ** = " + SCAN_INTERVAL_TIME);
t.schedule(scanTask, 0, SCAN_INTERVAL_TIME);
}
REFACTORED CODE
#Override
public void StartScanning() {
t.schedule(new ScanTask(),SCAN_INTERVAL_TIME);
}
class ScanTask extends TimerTask{
#Override
public void run() {
wifiManager.startScan();
scanCount++;
if(SCAN_INTERVAL_TIME < SCAN_MAX_INTERVAL)
SCAN_INTERVAL_TIME = SCAN_INTERVAL_TIME + SCAN_INCREASE_INTERVAL;
t.schedule(new ScanTask(), SCAN_INTERVAL_TIME);
}
}
It works now but is creating a new ScanTask() every time wasteful?
Here is how I would do it:
1) Schedule the task for a single execution rather than a repeated one
2) At the end of the execution (possibly in a finally block), schedule a new single execution of the task, with a longer delay. Note that you must create a new instance of the task, otherwise the timer will complain (IllegalStateException). That means that you can't use an anonymous inner class anymore.
I have one simple question regarding Java TimerTask. How do I pause/resume two TimerTask tasks based on a certain condition? For example I have two timers that run between each other. When a certain condition has been met inside the task of first timer, the first timer stops and starts the second timer, and the same thing happens when a certain condition has been met inside the task of second timer. The class below shows exactly what I mean:
public class TimerTest {
Timer timer1;
Timer timer2;
volatile boolean a = false;
public TimerTest() {
timer1 = new Timer();
timer2 = new Timer();
}
public void runStart() {
timer1.scheduleAtFixedRate(new Task1(), 0, 1000);
}
class Task1 extends TimerTask {
public void run() {
System.out.println("Checking a");
a = SomeClass.getSomeStaticValue();
if (a) {
// Pause/stop timer1, start/resume timer2 for 5 seconds
timer2.schedule(new Task2(), 5000);
}
}
}
class Task2 extends TimerTask{
public void run() {
System.out.println("Checking a");
a = SomeClass.getSomeStaticValue();
if (!a) {
// Pause/stop timer2, back to timer1
timer1.scheduleAtFixedRate(new Task1(), 0, 1000);
}
// Do something...
}
}
public static void main(String args[]) {
TimerTest tt = new TimerTest();
tt.runStart();
}
}
So my question is, how do I pause timer1 while running timer2 and vice versa while timer2 is running? Performance and timing is my main concern as this needs to be implemented inside another running thread. By the way I am trying to implement these concurrent timers on Android.
Thanks for your help!
From TimerTask.cancel():
Note that calling this method from
within the run method of a repeating
timer task absolutely guarantees that
the timer task will not run again.
So once cancelled, it won't ever run again. You'd be better off instead using the more modern ScheduledExecutorService (from Java 5+).
Edit: The basic construct is:
ScheduledExecutorService exec = Executors.newSingleThreadScheduledExecutor();
exec.scheduleAtFixedRate(runnable, 0, 1000, TimeUnit.MILLISECONDS);
but looking into it there's no way of cancelling that task once its started without shutting down the service, which is a bit odd.
TimerTask might be easier in this case but you'll need to create a new instance when you start one up. It can't be reused.
Alternatively you could encapsulate each task as a separate transient service:
final ScheduledExecutorService exec = Executors.newSingleThreadScheduledExecutor();
Runnable task1 = new Runnable() {
public void run() {
a++;
if (a == 3) {
exec.shutdown();
exec = Executors.newSingleThreadScheduledExecutor();
exec.scheduleAtFixedRate(task2, 0, 1000, TimeUnit.MILLISECONDS)
}
}
};
exec.scheduleAtFixedRate(task1, 0, 1000, TimeUnit.MILLISECONDS);
easiest solution i found: just add a boolean in the run code in the timer task, like so:
timer.schedule( new TimerTask() {
public void run() {
if(!paused){
//do your thing
}
}
}, 0, 1000 );
If you have already canceled one timer, you can't re-start it, you'll have to create a new one.
See this answer, it contains a video and the source code how I did something similar.
Basically there are two method: pause and resume
In pause:
public void pause() {
this.timer.cancel();
}
In resume:
public void resume() {
this.timer = new Timer();
this.timer.schedule( aTask, 0, 1000 );
}
That makes the perception of pause/resume.
If your timers perform different actions based on the state of the application you may consider use the StatePattern
Fist define a abstract state:
abstract class TaskState {
public void run();
public TaskState next();
}
And provide as many states as you like. The key is that one state leads you to another.
class InitialState extends TaskState {
public void run() {
System.out.println( "starting...");
}
public TaskState next() {
return new FinalState();
}
}
class FinalState extends TaskState {
public void run() {
System.out.println("Finishing...");
}
public TaskState next(){
return new InitialState();
}
}
And then you change the state in your timer.
Timer timer = new Timer();
TaskState state = new InitialState();
timer.schedule( new TimerTask() {
public void run() {
this.state.run();
if( shouldChangeState() ) {
this.state = this.state.next();
}
}
}, 0, 1000 );
Finally, if what you need is to perform the same thing, but at different rates, you may consider using the TimingFramework. It is a bit more complex but let's you do cool animations, by allowing the painting of certain component take place at different rates ( instead of being linear )
In my opinion, this is somewhat misguided. If your code needs time guarantees, you can't use Timer anyway, nor would you want to. "This class does not offer real-time guarantees: it schedules tasks using the Object.wait(long) method."
The answer, IMHO, is that you don't want to pause and restart your timers. You just want to suppress their run methods from doing their business. And that's easy: you just wrap them in an if statement. The switch is on, they run, the switch is off, they miss that cycle.
Edit: The question has shifted substantially from what it was originally, but I'll leave this answer in case it helps anyone. My point is: if you don't care when your event fires in the N millisecond span (just that it doesn't EXCEED once every N milliseconds), you can just use conditionals on the run methods. This is, in fact, a very common case, especially when N is less than 1 second.
Reviewing your source code, here are the changes ( which pretty much validate my previous answer )
In task1:
// Stop timer1 and start timer2
timer1.cancel();
timer2 = new Timer(); // <-- just insert this line
timer2.scheduleAtFixedRate(new Task2(), 0, 1000);
and in task2:
// Stop timer2 and start timer1
timer2.cancel();
timer1 = new Timer(); // <-- just insert this other
timer1.scheduleAtFixedRate(new Task1(), 0, 1000);
It runs on my machine:
Android won't reuse a TimerTask that has already been scheduled once. So it's necessary to reinstantiate both the Timer and TimerTask, for example like this in a Fragment:
private Timer timer;
private TimerTask timerTask;
public void onResume ()
{
super.onResume();
timer = new Timer();
timerTask = new MyTimerTask();
timer.schedule(timerTask, 0, 1000);
}
public void onPause ()
{
super.onPause();
timer.cancel(); // Renders Timer unusable for further schedule() calls.
}
I am able to stop a timer and a task using following code:
if(null != timer)
{
timer.cancel();
Log.i(LOG_TAG,"Number of cancelled tasks purged: " + timer.purge());
timer = null;
}
if(task != null)
{
Log.i(LOG_TAG,"Tracking cancellation status: " + task.cancel());
task = null;
}
Timer timer1;
private boolean videoCompleteCDR=false;
private boolean isVideoPlaying=false;
int videoTime=0;
private int DEFAULT_VIDEO_PLAY_TIME = 30;
#Override
public View onCreate(){
isVideoPlaying = true; //when server response is successfully
}
#Override
public void onPause() {
super.onPause();
if(isVideoPlaying ) {
if(this.timer1 !=null) {
this.timer1.cancel();
}
}
}
#Override
public void onResume() {
super.onResume();
if(isVideoPlaying && !videoCompleteCDR) {
callTimerTask();
}
}
#Override
public void onHiddenChanged(boolean hidden) {
super.onHiddenChanged(hidden);
if (!hidden) {
printLog( "GameFragment visible ");
if(isVideoPlaying && !videoCompleteCDR) {
callTimerTask();
}
} else {
printLog("GameFragment in visible ");
if(isVideoPlaying) {
if(this.timer1 !=null) {
this.timer1.cancel();
}
}
}
}
private void callTimerTask() {
// TODO Timer for auto sliding
printLog( "callTimerTask Start" );
timer1 = new Timer();
timer1.schedule(new TimerTask() {
#Override
public void run() {
if (getActivity() != null) {
getActivity().runOnUiThread(new Runnable() {
#Override
public void run() {
if (getActivity() == null) {
return;
}
videoTime++;
if(DEFAULT_VIDEO_PLAY_TIME ==videoTime){
videoCompleteCDR=true;
Log.e("KeshavTimer", "callTimerTask videoCompleteCDR called.... " +videoTime);
destroyTimer();
}
Log.e("KeshavTimer", "callTimerTask videoTime " +videoTime);
}
});
} else {
printLog("callTimerTask getActivity is null ");
}
}
}, 1000, 1000);
// TODO 300, 2000;
}
private void destroyTimer(){
this.timer1.cancel();
}