Develop Reference

Calling on click on button when timer ends

I'm creating a quiz app in android. I have written OnClickListener for next button to load next question. now I want to add timer to each question so that when timer ends it will automatically call OnClickListener of next button. How to implement this?

If you want to delay some code from running for a certain amount of time use a Runnable and a Handler like this
Runnable r = new Runnable() {
#Override
public void run(){
doSomething(); //<-- put your code in here.
}
};
Handler h = new Handler();
h.postDelayed(r, 1000);

You just need to call performClick() on an instance of your next button. Something like this:
nextButton.performClick()
That will execute everything you have inside of OnClickListener that is set for that button.
EDIT:
If I misunderstood your question and you are searching for Timer implementation, I recommend for you check CountDownTimer that is provided by Android team. You can check documentation with an example for his here:
https://developer.android.com/reference/android/os/CountDownTimer

You can have a method you call when the user clicks the next button say it's named as nextQuestion()
then add the listener of your next button
Button nextBtn = findViewById(..);
nextBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
nextQuestion();
}
});
And the time would be CountDownTimer of say 1 min duration (60*1000 msec) and 1 second tick (1000 msec)
new CountDownTimer(60000, 1000) { // 1 min duration (60*1000 msec) and 1 second tick (1000 msec)
#Override
public void onTick(long millisUntilFinished) {
// do something each second
}
#Override
public void onFinish() {
// timer expired
nextQuestion();
}
}.start();

Finish an activity after a time period

I am trying to develop a game like matching small pictures.My problem is that i want to finish the game after a time period.For instance in level 1 we have 10 seconds to match picture.I want to display remaining time also.I will be thankful for any help.

Since you also want to show the countdown, I would recommend a CountDownTimer. This has methods to take action at each "tick" which can be an interval you set in the constructor. And it's methods run on the UI Thread so you can easily update a TextView, etc...
In it's onFinish() method you can call finish() for your Activity or do any other appropriate action.
See this answer for an example
Edit with more clear example
Here I have an inner-class which extends CountDownTimer
#Override
public void onCreate(Bundle savedInstanceState) {
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
super.onCreate(savedInstanceState);
setContentView(R.layout.some_xml);
// initialize Views, Animation, etc...
// Initialize the CountDownClass
timer = new MyCountDown(11000, 1000);
}
// inner class
private class MyCountDown extends CountDownTimer
{
public MyCountDown(long millisInFuture, long countDownInterval) {
super(millisInFuture, countDownInterval);
frameAnimation.start();
start();
}
#Override
public void onFinish() {
secs = 10;
// I have an Intent you might not need one
startActivity(intent);
YourActivity.this.finish();
}
#Override
public void onTick(long duration) {
cd.setText(String.valueOf(secs));
secs = secs - 1;
}
}

#nKn described it pretty well.
However, if you do not want to mess around with Handler. You always can delay the progress of the system code by writing:
Thread.sleep(time_at_mili_seconds);
You probably need to surround it with try-catch, which you can easily add via Source-> Surround with --> Try & catch.

You can use postDelayed() method of Handler...pass a Thread and specific time after which time the Thread will be executed as below...
private Handler mTimerHandler = new Handler();
private Runnable mTimerExecutor = new Runnable() {
#Override
public void run() {
//here, write your code
}
};
Then call postDelayed() method of Handler to execute after your specified time as below...
mTimerHandler.postDelayed(mTimerExecutor, 10000);

Android countdown

I want to write a countdown in android which starts counting from 3 to 0. Like at first 3 in appearing and then disappearing and 2 is appearing and so on. I searched a lot but I couldn't find any good sample. Can you help me that what should I do?

use CountDownTimer
For example:
import android.os.CountDownTimer;
MyCount timerCount;
public class TestCountdown extends Activity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
timerCount = new MyCount(3 * 1000, 1000);
timerCount.start();
}
public class MyCount extends CountDownTimer {
public MyCount(long millisInFuture, long countDownInterval) {
super(millisInFuture, countDownInterval);
}
#Override
public void onFinish() {
//some script here
}
#Override
public void onTick(long millisUntilFinished) {
//some script here
}
}
}

The good guys in Android thought about you.
You have a class for that - CountDownTimer.

I am not going to write you the code for this but this should not be difficult.Just use a thread to display the value 3(using say TextView) first then sleep for say (100ms assuming you want it to change after 1 sec) then decrease it and repeat.
An example would be
for i=0 to 3
print the number
thread.sleep(100)

How to show remaining time in digital clock?

am creating one application for student. I need to show digital clock with remaining time.
here i add digital clock
but it show system date
and i need to show Remaining time means suppose if exam time is 10 minute then it must show
time in reverse manner. Or i need to use another clock.
Any help is Appreciated.

Define this code in onCreate.
// 5000 is the starting number (in milliseconds)
// 1000 is the number to count down each time (in milliseconds)
MyCount counter = new MyCount(5000, 1000);
counter.start();
Constructor for CountDownTimer is as follow.
// countdowntimer is an abstract class, so extend it and fill in methods
public class MyCount extends CountDownTimer{
public MyCount(long millisInFuture, long countDownInterval) {
super(millisInFuture, countDownInterval);
}
#Override
public void onFinish() {
tv.setText(”done!”); //TextView object should be defined in onCreate
}
#Override
public void onTick(long millisUntilFinished) {
tv.setText(”Left: ” + millisUntilFinished/1000);// This will be called every Second.
}
}

Take a look at the CountDownTimer-class.

Capture the countdown timer in different activities

I´am designing a countdown timer, that works perfectly but only If I stay in this Activity. Because, if the countdown starts and I go back for example and start other Activity, the countdonws follows counting down. And logically if I start again the activty where the countdown timer is, it appears like nothing is counting down, but in the bacground is counting down, I know because on the ontick of the timer, I throw a continue notification to show it at the notification tab.
The code is bellow, sendnotification method is a method that throws a alert when the time finishes, and the sendnotificationTiempo to send a notification to the tab every second to show at the top.
public static final int NOTIFICATION_ID = 33;
public static final int NOTIFICATION_ID_Tiempo = 34;
private int minCrono;
TextView text;
MyCounter timer;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
StartCrono = (Button) findViewById(R.id.butt_start);
CancelCrono = (Button) findViewById(R.id.butt_cancel);
text=(TextView)findViewById(R.id.text_countTime1);
CancelCrono.setEnabled(false);
minCrono = mins.getCurrentItem();
StartCrono.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
minCrono=(60000*minCrono);
timer = new MyCounter(minCrono,1000);
timer.start();
}
});
CancelCrono.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
timer.cancel();
text.setText("El tiempo se ha cancelado");
minutosCrono = mins.getCurrentItem();
if (mNotificationManager != null)
mNotificationManager.cancel(NOTIFICATION_ID_Tiempo);
}
});
}
Countdown Class:
public class MyCounter extends CountDownTimer{
public MyCounter(long millisInFuture, long countDownInterval) {
super(millisInFuture, countDownInterval);
}
#Override
public void onFinish() {
StartCrono.setEnabled(true);
CancelCrono.setEnabled(false);
mins.setEnabled(true);
minCrono = mins.getCurrentItem();
//
text.setText("Time Complete!");
sendnotification("Guau", "Time finished.");
}
#Override
public void onTick(long millisUntilFinished) {
long segRestantesTotal=(millisUntilFinished/1000);
long minRestantes= (segRestantesTotal/60);
long segRestantes= (segRestantesTotal%60);
if(segRestantes>=10){
text.setText(minRestantes+":"+segRestantes);
sendnotificationTiempo("Guau", minRestantes+":"+segRestantes);
}
else{
text.setText(minRestantes+":0"+segRestantes);
sendnotificationTiempo("Guau", minRestantes+":0"+segRestantes);
}
}
}
}
So what I would to do, is to know when I go back the Activity and I start another one, to show the time what is counting down at the background to show it for example in a textview.
Or maybe if I can get the time that is counting down from the notification tab perfect.
Thanks!

Move your MyCounter instance out of the Activity. When the Activity restarts, the instance is being recreated so the old one is gone. There are a couple ways you can do this, but you need to have your MyCounter instance live somewhere that the Activity can access it but isn't responsible for its life cycle. I use a rudimentary ServiceLocator implementation that I wrote, but you can easily create a custom Application class and keep the timer (or a controller class that creates and controls the timer) there.