I have a simple stopwatch code piece. Thread is running in custom class, it connects to the main activity via Interface
public class MainActivity extends AppCompatActivity implements MainActivityInteractionInterface{
public static boolean isRunning = false;
Stopwatch stopWatch;
private TextView textViewMilliSeconds;
private TextView textViewSeconds;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textViewMilliSeconds = findViewById(R.id.textViewStopwatchMilliseconds);
textViewSeconds = findViewById(R.id.textViewStopwatchSeconds);
stopWatch = new Stopwatch(this, getApplicationContext());
stopWatch.runThread();
}
#Override
public void updateUI() {
String time = String.format(Locale.getDefault(), "%03d", stopWatch.getMilliseconds());
textViewMilliSeconds.setText(time);
String timeSeconds = String.format(Locale.getDefault(), "%02d", stopWatch.getSeconds());
textViewSeconds.setText(timeSeconds);
}
public void startTimer(View view) {
isRunning = !isRunning;
}
public class Stopwatch {
private int milliseconds = 0;
private int seconds = 0;
public int getMilliseconds() {
return milliseconds;
}
public int getSeconds() {
return seconds;
}
private MainActivityInteractionInterface interactionInterface;
private Context applicationContext;
public Stopwatch(MainActivityInteractionInterface interactionInterface, Context applicationContext){
this.interactionInterface = interactionInterface;
this.applicationContext = applicationContext;
}
public void runThread(){
final Handler handler = new Handler();
handler.post(new Runnable(){
#Override
public void run(){
if(isRunning) {
milliseconds++;
if (milliseconds == 1000) {
milliseconds = 0;
seconds++;
if(seconds == 60){
seconds = 0;
}
}
}
interactionInterface.updateUI();
handler.postDelayed(this, 1);
}
});
}
handler should update every 1 millisec, when there is 1000 milliseconds, 1 second passes by
If I set handler.postDelayed delay anything below 15 reaching 1000 milliseconds would take exactly 18 seconds, why?
I don't know why it would take up to 18seconds, but I can tell you this: Android refresh the UI every 16msec (to have a rate of 60fps), so setting the handler to updateUI in a lesser time would make no sense and maybe also interfier with it.
In my humble opinion, make it to update in 20msec and change the counter values according, like this:
handler.post(new Runnable(){
#Override
public void run(){
if(isRunning) {
milliseconds++;
if (milliseconds == 50) {
milliseconds = 0;
seconds++;
if(seconds == 60){
seconds = 0;
}
}
}
interactionInterface.updateUI();
handler.postDelayed(this, 20);
}
});
Look at the second argument of handler.postDelayed(this, 1);
Change it according to the way you increment your milliseconds.
I'm creating a timer app that utilizes a thread. When I exit the app using the home button the timer is running fine. Usually, when the time is up a dialog is launched that asks the user for some input. This works completely fine if the app is in its onResume() state, however when the app is in its onStop() state the dialog will not launch and an error is thrown.
java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
How can I make it so that when the time is up and the app is NOT in the foreground the dialog is still launched. My initial thought was to save the time remaining in the bundle, but the time remaining is changing for every single tick. Then I thought about storing a boolean in the bundle mTimeRunning. However, when the time is up this value must also change. So now I'm drawing a blank. What can I possibly do so that the dialog is launched when the app is not in the foreground?
TimerActivity.java
public class TimerActivity extends AppCompatActivity implements TimeDialogFragment.sendMinutes,
TimeFinishDialogFragment.sendResponse, BreakFinishDialogFragment.userResponse {
// Variable to log activity state
private static final String TAG = "TimerActivity";
private static final boolean DEBUG = true;
// ^^ Variable used to log acitivty state
private Handler mHandler;
private Runnable mRunnable;
//private static final long START_TIME_MILLISECONDS = 600000;
// Below start time is for development purposes only
private static long mStartTime = 10000;
private long mTimeRemaining = mStartTime;
private boolean mTimeRunning;
private boolean mBreakTime = false;
private ProgressBar mTimeBar;
private TextView mTime;
private Button mStartPause;
private Button mSetTime;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_timer);
if(DEBUG) Log.d(TAG, "+ onCreate() +");
mHandler = new Handler();
mTimeBar = findViewById(R.id.time_bar);
mTime = findViewById(R.id.text_view_time);
mStartPause = findViewById(R.id.button_start_pause);
mSetTime = findViewById(R.id.button_set_time);
updateCountDownText();
mTimeBar.setMax((int) mTimeRemaining);
mSetTime.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
//FragmentManager manager = getSupportFragmentManager();
DialogFragment setTime = new TimeDialogFragment();
setTime.show(getFragmentManager(),"SET_TIME_DIALOG");
}
});
mStartPause.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if(mTimeRunning){
//pauseTimer();
mTimeRunning = false;
mStartPause.setText("Start");
mHandler.removeCallbacks(mRunnable);
}else{
//startTimer();
timer();
}
}
});
}
// Using a handler + anon runnable
private void timer(){
mRunnable = new Runnable() {
#Override
public void run() {
mTimeRunning = true;
mStartPause.setText("Pause");
mTimeRemaining = mTimeRemaining - 1000;
updateCountDownText();
mTimeBar.incrementProgressBy(1000);
if(mTimeRemaining > 0) {
mHandler.postDelayed(this, 1000);
}else{
// if breaktime is false
if(!mBreakTime) {
DialogFragment dialog = new TimeFinishDialogFragment();
dialog.show(getFragmentManager(),"TIME_FINISH_DIALOG");
mTimeRunning = false;
}else{
// launch break time up dialog.
mBreakTime = false;
DialogFragment dialog = new BreakFinishDialogFragment();
dialog.show(getFragmentManager(), "BREAK_FINSIH_DIALOG");
}
}
}
};
mHandler.postDelayed(mRunnable,1000);
}
public void updateCountDownText(){
int min = (int) (mTimeRemaining / 1000) / 60;
int sec = (int) (mTimeRemaining / 1000) % 60;
String formattedString = String.format(Locale.getDefault(), "%02d:%02d", min, sec);
mTime.setText(formattedString);
}
public void setCountDownText(long time){
int min = (int) (time / 1000) / 60;
int sec = (int) (time / 1000) % 60;
String formattedString = String.format(Locale.getDefault(), "%02d:%02d", min, sec);
mTime.setText(formattedString);
}
#Override
public void userTime(int minutes) {
TimerActivity.mStartTime = (minutes * 60) * 1000;
mTimeRemaining = TimerActivity.mStartTime;
mTimeBar.setMax((int) mTimeRemaining);
setCountDownText(mTimeRemaining);
}
#Override
public void sendResponse(int val) {
if(val == -1){
mTimeRemaining = TimerActivity.mStartTime;
mTimeBar.setMax((int) mTimeRemaining);
updateCountDownText();
mTimeBar.setProgress(0);
mStartPause.setText("Start");
}else if(val == 1) {
mBreakTime = true;
mTimeRemaining = 15000;
mTimeBar.setMax((int) mTimeRemaining);
setCountDownText(mTimeRemaining);
mTimeBar.setProgress(0);
mStartPause.setVisibility(View.INVISIBLE);
timer();
}else {
mTimeRemaining = TimerActivity.mStartTime;
mTimeBar.setMax((int) mTimeRemaining);
updateCountDownText();
mTimeBar.setProgress(0);
timer();
}
}
#Override
public void userResponse(int val) {
if(val < 0) {
// user clicked cance
mTimeRemaining = TimerActivity.mStartTime;
mTimeBar.setMax((int) mTimeRemaining);
updateCountDownText();
mTimeBar.setProgress(0);
mStartPause.setText("Start");
}else {
mTimeRemaining = TimerActivity.mStartTime;
mTimeBar.setMax((int) mTimeRemaining);
updateCountDownText();
mTimeBar.setProgress(0);
timer();
}
mStartPause.setVisibility(View.VISIBLE);
}
TimeFinishedDialog.java
public class TimeFinishDialogFragment extends DialogFragment implements View.OnClickListener{
private Button mCancel;
private Button mSkip;
private Button mStartBreak;
private sendResponse mResponse;
interface sendResponse{
void sendResponse(int val);
}
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
//return super.onCreateDialog(savedInstanceState);
View view = LayoutInflater.from(getActivity()).inflate(R.layout.time_finish_dialog_fragment, null, false);
mCancel = view.findViewById(R.id.button_cancel);
mSkip = view.findViewById(R.id.button_skip);
mStartBreak = view.findViewById(R.id.button_start_break);
mCancel.setOnClickListener(this);
mSkip.setOnClickListener(this);
mStartBreak.setOnClickListener(this);
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
builder.setView(view)
.setTitle("Start Break?");
AlertDialog dialog = builder.create();
dialog.setContentView(view);
return dialog;
}
#Override
public void onClick(View view) {
switch(view.getId()){
case R.id.button_cancel:
mResponse.sendResponse(-1);
getDialog().dismiss();
break;
case R.id.button_skip:
mResponse.sendResponse(0);
getDialog().dismiss();
break;
case R.id.button_start_break:
mResponse.sendResponse(1);
getDialog().dismiss();
break;
default:
break;
}
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
try{
mResponse = (sendResponse) getActivity();
}catch (ClassCastException e){
System.out.println("Error: " + e);
}
}
}
when the time is up and the app is NOT in the foreground the dialog is still launched
You should not be doing this since this will interrupt the user from doing other work which they might be doing at that time and this can be irritating.
What can I possibly do so that the dialog is launched when the app is not in the foreground?
You can show the dialog only the user is actively using your application or you can fall back to show a notification when the user is not using the app.
And if you desperately want to show a dialog, you can try a dialog themed activity
So I'm doing an Android game for an assignment resit. This is not my first app but it is my first game. I've never been that much of an expert and quite frankly this is hard for me. I hope someone here can help.
I actually have two problems to add a score (I sincerely hope it's not too much). The thing is, I want to display it in a TextView. When the Sprite "bad" is hit, I want the score to increase by 1.
My first problem is that said TextView doesn't appear on my activity even when I'm not putting anything else than text in it. I tried to put it in LinearLayout, or change some parameters for its position, but I didn't find any other helpful thing on internet.
My second problem is for the score, which even if I can't see it, probably doesn't work. I found some helps saying to put a JPanel or JLabel but I don't think this is what I need. I tried a simple thing where I just made it an int that increases in the isHit and then displays it on the page. But it doesn't display anything, and the program took the bad habit of crashing before I can't even do anything when I have these written in the code.
I don't actually know which other page would be useful, so here is my GameView.java, if any other might be needed, please tell me.
package com.example.proprietaire.assignmentna2;
import com.example.proprietaire.assignmentna2.R;
import com.example.proprietaire.assignmentna2.Sprite;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.List;
public class GameView extends SurfaceView implements Runnable {
private SurfaceHolder holder;
private int x = 0, xSpeed = 1;
private Bitmap bmp;
Thread thread = null;
volatile boolean running = false;
static final long FPS = 10;
private long lastClick;
private List<Sprite> sprites = new ArrayList<Sprite>();
private List<Sprite> sprites2 = new ArrayList<Sprite>();
private List<TempSprite> temps = new ArrayList<TempSprite>();
private Bitmap bmpSmoke;
int score = 0;
public GameView(Context context) {
super(context);
thread = new Thread(this);
holder = getHolder();
holder.addCallback(new SurfaceHolder.Callback() {
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
boolean retry = true;
running = false;
while (retry) {
try {
thread.join();
retry = false;
} catch (InterruptedException e) {
}
}
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
createSprites();
running = true;
thread.start();
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format,
int width, int height) {
}
});
bmpSmoke = BitmapFactory.decodeResource(getResources(), R.drawable.smoke);
}
private void createSprites() {
sprites.add(createSprite(R.drawable.bad));
sprites2.add(createSprite(R.drawable.good));
}
private Sprite createSprite(int resource) {
bmp = BitmapFactory.decodeResource(getResources(), resource);
return new Sprite(this, bmp);
}
#Override
protected void onDraw(Canvas canvas) {
canvas.drawColor(Color.WHITE);
for (int i = temps.size() - 1; i>= 0; i--) {
temps.get(i).onDraw(canvas);
}
for (Sprite sprite : sprites) {
sprite.onDraw(canvas);
}
for (Sprite sprite : sprites2) {
sprite.onDraw(canvas);
}
}
#Override
public void run() {
long ticksPS = 1000 / FPS;
long startTime;
long sleepTime;
while (running) {
Canvas c = null;
startTime = System.currentTimeMillis();
try {
c = getHolder().lockCanvas();
synchronized (getHolder()) {
onDraw(c);
}
} finally {
if (c != null) {
getHolder().unlockCanvasAndPost(c);
}
}
sleepTime = ticksPS - (System.currentTimeMillis() - startTime);
try {
if (sleepTime > 0)
thread.sleep(sleepTime);
else
thread.sleep(10);
} catch (Exception e) {
}
}
}
#Override
public boolean onTouchEvent(MotionEvent event) {
if (System.currentTimeMillis() - lastClick> 300) {
lastClick = System.currentTimeMillis();
float x = event.getX();
float y = event.getY();
synchronized (getHolder()) {
for (int i = sprites.size() - 1; i >= 0; i--) {
Sprite sprite = sprites.get(i);
if (sprite.isHit(event.getX(), event.getY())) {
sprites.remove(sprite);
temps.add(new TempSprite(temps, this, x, y, bmpSmoke));
sprites.add(createSprite(R.drawable.bad));
sprites.add(createSprite(R.drawable.bad));
sprites2.add(createSprite(R.drawable.good));
score++;
break;
}
//TextView textView = (TextView)findViewById(R.id.textView);
//String s = "" + score;
//textView.setText((new Integer(score)).toString(Integer.parseInt(s)));
}
}
}
return true;
}
}
Here is GameActivity.java
package com.example.proprietaire.assignmentna2;
import android.app.Activity;
import android.os.Bundle;
public class GameActivity extends Activity {
GameView GV;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
GV = new GameView(this);
setContentView(GV);
}
}
The xml for the game is a simple TextView without any special thing added.
Thank you in advance.
I just checked some of my old code when I was making my own game, I made a dummy .xml file with nothing but a RelativeLayout in it. So your `GameActivity would look something like this:
private TextView tv;
private GameView gv;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.dummyXml);
initializeGameView();
}
From this point on, you can play around with your GameView and your TextView. I will give an example of the start:
private void initializeGameView(){
RelativeLayout rl = (RelativeLayout) findViewById(R.id.rl_dummy_xml);
LinearLayout ll = new LinearLayout(this);
//Layout stuff
ll.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
ll.setOrientation(LinearLayout.VERTICAL);
ll.setGravity(Gravity.CENTER_HORIZONTAL);
//add more stuff, play around with whatever you want to do here
gv = new GameView();
ll.addView(gv);
tv = new TextView(this);
tv.setText(gv.getScore());
ll.addView(tv);
//Finally, don't forget to add the linear layout to the relative layout
rl.addView(ll);
}
Add a getScore() method to your GameView class or alternatively in a more elegant location :P
If you still have questions (after you've tried and tried and tried), feel free to ask ahead! =)
EDIT:
Updated code example with init of the TextView tv. If you want to update the textview you added at any point, add a method toughly similar to this one:
public void updateTextViewScore(){
tv.setText(gv.getScore());
}
I made the GameView and TextView variables global, therefore you can access them in any method you wish.
You probably want to call this method (thus update the textview) inside the game loop e.g. whenever the score changes.
Good luck! Hope this clears it up a bit.
I was trying to build some sort of sequential countdown. Meaning, that I build up a queue of "exercises", each one containing a specific duration, which is the countdown time. In a custom Countdown class, I pop these exercises off the queue and use the duration as countdown.
I want these countdowns to run one after another. For this I built a Countdown class, based on the code basis of the abstract class CountDownTimer.
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Locale;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.os.SystemClock;
import android.widget.Button;
import android.widget.TextView;
public class ExerciseMeCountDownTimer {
private static final int MSG_COUNTDOWN = 100;
private static final int MSG_FINISH = 99;
private ArrayDeque<Exercise> eq;
private long mMillisInFuture;
private int mCountdownInterval;
private String name;
private long mStopTimeInFuture;
CountdownHandler cHandler;
public ExerciseMeCountDownTimer(ArrayList<Exercise> elist,
Button startStopButton, TextView countdownText,
CountdownHandler cHandler) {
this.cHandler = cHandler;
eq = new ArrayDeque<Exercise>(elist);
this.start();
}
public final void cancel() {
mHandler.removeMessages(MSG);
}
private synchronized final ExerciseMeCountDownTimer start() {
if (!eq.isEmpty()) {
Exercise e = eq.pop();
this.mMillisInFuture = Long.parseLong(e.getDuration());
this.mCountdownInterval = 30;
this.name = e.getName();
} else {
onFinish();
return this;
}
if (mMillisInFuture <= 0) {
onFinish();
return this;
}
mStopTimeInFuture = SystemClock.elapsedRealtime() + mMillisInFuture;
mHandler.sendMessage(mHandler.obtainMessage(MSG));
return this;
}
public void onTick(long millisUntilFinished) {
Message msg = cHandler.obtainMessage(MSG_COUNTDOWN);
Bundle data = new Bundle();
String text = String.format(Locale.GERMANY, "%02d:%02d:%03d",
millisUntilFinished / 100000, millisUntilFinished / 1000,
millisUntilFinished % 1000);
data.putString("countdown", text);
msg.setData(data);
cHandler.sendMessage(msg);
}
public void onFinish() {
if (!eq.isEmpty()) {
this.start();
}
Message msg = cHandler.obtainMessage(MSG_FINISH);
Bundle data = new Bundle();
String text = String.format(Locale.GERMANY, "00:00:000");
data.putString("finish", text);
msg.setData(data);
cHandler.sendMessage(msg);
}
private static final int MSG = 1;
// handles counting down
private Handler mHandler = new Handler() {
#Override
public void handleMessage(Message msg) {
final long millisLeft = mStopTimeInFuture
- SystemClock.elapsedRealtime();
if (millisLeft <= 0) {
onFinish();
} else if (millisLeft < mCountdownInterval) {
// no tick, just delay until done
sendMessageDelayed(obtainMessage(MSG), millisLeft);
} else {
long lastTickStart = SystemClock.elapsedRealtime();
onTick(millisLeft);
// take into account user's onTick taking time to
// execute
long delay = lastTickStart + mCountdownInterval
- SystemClock.elapsedRealtime();
// special case: user's onTick took more than interval
// to
// complete, skip to next interval
while (delay < 0)
delay += mCountdownInterval;
sendMessageDelayed(obtainMessage(MSG), delay);
}
}
};
#Override
public String toString() {
return this.name;
}
}
The important part is the sendMessage part, where I send the time left on the countdown to a handler of my MainActivity, which then, should update a textview.
import android.os.Handler;
import android.os.Message;
class CountdownHandler extends Handler {
private static final int MSG_COUNTDOWN = 100;
private static final int MSG_FINISH = 99;
private MainActivity mActivity;
CountdownHandler(MainActivity activity) {
this.mActivity = activity;
}
#Override
public void handleMessage(Message msg) {
if (msg.what == MSG_COUNTDOWN) {
String text = msg.getData().getString("countdown");
this.mActivity.sayLog(text);
}
if (msg.what == MSG_FINISH) {
String text = msg.getData().getString("finish");
this.mActivity.sayLog(text);
}
}
And finally updates the textView in MainActivty
public void sayLog(String text) {
countdown.setText(text);
}
ExerciseMeCountDownTimer is called by
new ExerciseMeCountDownTimer(elist, cHandler);
on some onClick().
The problem is, that sometimes (actually most of the time) the textView is not updated properly. It stops updating on random times like 00:05:211 etc.
Would anyone mind telling me why this is keeps happening? Maybe also adding a solution or at least some literature (maybe pointing out some sections) which I should read to understand the problem? I am also upen for alternative approaches, as I am new to this "handler", "threads" thing in android.
EDIT
the textview was updating, but the textview was clickable. Whenever I clicked on the textview it stopped updating!
as the accepted answer shows, I decided to use the direkt approach of updating the appropriate textview inside the onTick() method.
Using Handler and things in this situation is making it overly complicated.
CountDownTimers onTick() and onFinish() both run on the UI Thread so updating TextViews and other Views from either method can be done easily just by passing a reference of the View to the constructor of the class, as you are already doing. Then you simply update it in the method needed.
// could create a member variable for the TextView with your other member variables
...
mTV;
then in your constructor assign it
// removed reference to Handler--you already have reference to TextView here
public ExerciseMeCountDownTimer(ArrayList elist,
Button startStopButton, TextView countdownText) {
mTV = countdownText;
then update in whichever method is needed
public void onTick(long millisUntilFinished) {
String text = String.format(Locale.GERMANY, "%02d:%02d:%03d",
millisUntilFinished / 100000, millisUntilFinished / 1000,
millisUntilFinished % 1000);
mTV.setText(text); // set the text here
}
public void onFinish() {
if (!eq.isEmpty()) {
this.start();
}
Can someone give a simple example of updating a textfield every second or so?
I want to make a flying ball and need to calculate/update the ball coordinates every second, that's why I need some sort of a timer.
I don't get anything from here.
ok since this isn't cleared up yet there are 3 simple ways to handle this.
Below is an example showing all 3 and at the bottom is an example showing just the method I believe is preferable. Also remember to clean up your tasks in onPause, saving state if necessary.
import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.os.Handler.Callback;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class main extends Activity {
TextView text, text2, text3;
long starttime = 0;
//this posts a message to the main thread from our timertask
//and updates the textfield
final Handler h = new Handler(new Callback() {
#Override
public boolean handleMessage(Message msg) {
long millis = System.currentTimeMillis() - starttime;
int seconds = (int) (millis / 1000);
int minutes = seconds / 60;
seconds = seconds % 60;
text.setText(String.format("%d:%02d", minutes, seconds));
return false;
}
});
//runs without timer be reposting self
Handler h2 = new Handler();
Runnable run = new Runnable() {
#Override
public void run() {
long millis = System.currentTimeMillis() - starttime;
int seconds = (int) (millis / 1000);
int minutes = seconds / 60;
seconds = seconds % 60;
text3.setText(String.format("%d:%02d", minutes, seconds));
h2.postDelayed(this, 500);
}
};
//tells handler to send a message
class firstTask extends TimerTask {
#Override
public void run() {
h.sendEmptyMessage(0);
}
};
//tells activity to run on ui thread
class secondTask extends TimerTask {
#Override
public void run() {
main.this.runOnUiThread(new Runnable() {
#Override
public void run() {
long millis = System.currentTimeMillis() - starttime;
int seconds = (int) (millis / 1000);
int minutes = seconds / 60;
seconds = seconds % 60;
text2.setText(String.format("%d:%02d", minutes, seconds));
}
});
}
};
Timer timer = new Timer();
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
text = (TextView)findViewById(R.id.text);
text2 = (TextView)findViewById(R.id.text2);
text3 = (TextView)findViewById(R.id.text3);
Button b = (Button)findViewById(R.id.button);
b.setText("start");
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Button b = (Button)v;
if(b.getText().equals("stop")){
timer.cancel();
timer.purge();
h2.removeCallbacks(run);
b.setText("start");
}else{
starttime = System.currentTimeMillis();
timer = new Timer();
timer.schedule(new firstTask(), 0,500);
timer.schedule(new secondTask(), 0,500);
h2.postDelayed(run, 0);
b.setText("stop");
}
}
});
}
#Override
public void onPause() {
super.onPause();
timer.cancel();
timer.purge();
h2.removeCallbacks(run);
Button b = (Button)findViewById(R.id.button);
b.setText("start");
}
}
the main thing to remember is that the UI can only be modified from the main ui thread so use a handler or activity.runOnUIThread(Runnable r);
Here is what I consider to be the preferred method.
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class TestActivity extends Activity {
TextView timerTextView;
long startTime = 0;
//runs without a timer by reposting this handler at the end of the runnable
Handler timerHandler = new Handler();
Runnable timerRunnable = new Runnable() {
#Override
public void run() {
long millis = System.currentTimeMillis() - startTime;
int seconds = (int) (millis / 1000);
int minutes = seconds / 60;
seconds = seconds % 60;
timerTextView.setText(String.format("%d:%02d", minutes, seconds));
timerHandler.postDelayed(this, 500);
}
};
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.test_activity);
timerTextView = (TextView) findViewById(R.id.timerTextView);
Button b = (Button) findViewById(R.id.button);
b.setText("start");
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Button b = (Button) v;
if (b.getText().equals("stop")) {
timerHandler.removeCallbacks(timerRunnable);
b.setText("start");
} else {
startTime = System.currentTimeMillis();
timerHandler.postDelayed(timerRunnable, 0);
b.setText("stop");
}
}
});
}
#Override
public void onPause() {
super.onPause();
timerHandler.removeCallbacks(timerRunnable);
Button b = (Button)findViewById(R.id.button);
b.setText("start");
}
}
It is simple!
You create new timer.
Timer timer = new Timer();
Then you extend the timer task
class UpdateBallTask extends TimerTask {
Ball myBall;
public void run() {
//calculate the new position of myBall
}
}
And then add the new task to the Timer with some update interval
final int FPS = 40;
TimerTask updateBall = new UpdateBallTask();
timer.scheduleAtFixedRate(updateBall, 0, 1000/FPS);
Disclaimer: This is not the ideal solution. This is solution using the Timer class (as asked by OP). In Android SDK, it is recommended to use the Handler class (there is example in the accepted answer).
If you also need to run your code on UI thread (and not on timer thread), take a look on the blog: http://steve.odyfamily.com/?p=12
public class myActivity extends Activity {
private Timer myTimer;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.main);
myTimer = new Timer();
myTimer.schedule(new TimerTask() {
#Override
public void run() {
TimerMethod();
}
}, 0, 1000);
}
private void TimerMethod()
{
//This method is called directly by the timer
//and runs in the same thread as the timer.
//We call the method that will work with the UI
//through the runOnUiThread method.
this.runOnUiThread(Timer_Tick);
}
private Runnable Timer_Tick = new Runnable() {
public void run() {
//This method runs in the same thread as the UI.
//Do something to the UI thread here
}
};
}
If one just want to schedule a countdown until a time in the future with regular notifications on intervals along the way, you can use the CountDownTimer class that is available since API level 1.
new CountDownTimer(30000, 1000) {
public void onTick(long millisUntilFinished) {
editText.setText("Seconds remaining: " + millisUntilFinished / 1000);
}
public void onFinish() {
editText.setText("Done");
}
}.start();
This is some simple code for a timer:
Timer timer = new Timer();
TimerTask t = new TimerTask() {
#Override
public void run() {
System.out.println("1");
}
};
timer.scheduleAtFixedRate(t,1000,1000);
I think you can do it in Rx way like:
timerSubscribe = Observable.interval(1, TimeUnit.SECONDS)
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Action1<Long>() {
#Override
public void call(Long aLong) {
//TODO do your stuff
}
});
And cancel this like:
timerSubscribe.unsubscribe();
Rx Timer http://reactivex.io/documentation/operators/timer.html
I'm surprised that there is no answer that would mention solution with RxJava2. It is really simple and provides an easy way to setup timer in Android.
First you need to setup Gradle dependency, if you didn't do so already:
implementation "io.reactivex.rxjava2:rxjava:2.x.y"
(replace x and y with current version number)
Since we have just a simple, NON-REPEATING TASK, we can use Completable object:
Completable.timer(2, TimeUnit.SECONDS, Schedulers.computation())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(() -> {
// Timer finished, do something...
});
For REPEATING TASK, you can use Observable in a similar way:
Observable.interval(2, TimeUnit.SECONDS, Schedulers.computation())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(tick -> {
// called every 2 seconds, do something...
}, throwable -> {
// handle error
});
Schedulers.computation() ensures that our timer is running on background thread and .observeOn(AndroidSchedulers.mainThread()) means code we run after timer finishes will be done on main thread.
To avoid unwanted memory leaks, you should ensure to unsubscribe when Activity/Fragment is destroyed.
Because this question is still attracting a lot of users from google search(about Android timer) I would like to insert my two coins.
First of all, the Timer class will be deprecated in Java 9 (read the accepted answer).
The official suggested way is to use ScheduledThreadPoolExecutor which is more effective and features-rich that can additionally schedule commands to run after a given delay, or to execute periodically. Plus,it gives additional flexibility and capabilities of ThreadPoolExecutor.
Here is an example of using plain functionalities.
Create executor service:
final ScheduledExecutorService SCHEDULER = Executors.newScheduledThreadPool(1);
Just schedule you runnable:
final Future<?> future = SCHEDULER.schedule(Runnable task, long delay,TimeUnit unit);
You can now use future to cancel the task or check if it is done for example:
future.isDone();
Hope you will find this useful for creating a tasks in Android.
Complete example:
ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
Future<?> sampleFutureTimer = scheduler.schedule(new Runnable(), 120, TimeUnit.SECONDS);
if (sampleFutureTimer.isDone()){
// Do something which will save world.
}
for whom wants to do this in kotlin:
val timer = fixedRateTimer(period = 1000L) {
val currentTime: Date = Calendar.getInstance().time
runOnUiThread {
tvFOO.text = currentTime.toString()
}
}
for stopping the timer you can use this:
timer.cancel()
this function has many other options, give it a try
import kotlin.concurrent.fixedRateTimer
val timer = fixedRateTimer("Tag", false, 1000, 2500) { /* Your code here */ }
Pretty simple with Kotlin
You want your UI updates to happen in the already-existent UI thread.
The best way is to use a Handler that uses postDelayed to run a Runnable after a delay (each run schedules the next); clear the callback with removeCallbacks.
You're already looking in the right place, so look at it again, perhaps clarify why that code sample isn't what you want. (See also the identical article at Updating the UI from a Timer).
He're is simplier solution, works fine in my app.
public class MyActivity extends Acitivity {
TextView myTextView;
boolean someCondition=true;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.my_activity);
myTextView = (TextView) findViewById(R.id.refreshing_field);
//starting our task which update textview every 1000 ms
new RefreshTask().execute();
}
//class which updates our textview every second
class RefreshTask extends AsyncTask {
#Override
protected void onProgressUpdate(Object... values) {
super.onProgressUpdate(values);
String text = String.valueOf(System.currentTimeMillis());
myTextView.setText(text);
}
#Override
protected Object doInBackground(Object... params) {
while(someCondition) {
try {
//sleep for 1s in background...
Thread.sleep(1000);
//and update textview in ui thread
publishProgress();
} catch (InterruptedException e) {
e.printStackTrace();
};
return null;
}
}
}
You can also use an animator for it:
int secondsToRun = 999;
ValueAnimator timer = ValueAnimator.ofInt(secondsToRun);
timer.setDuration(secondsToRun * 1000).setInterpolator(new LinearInterpolator());
timer.addUpdateListener(new ValueAnimator.AnimatorUpdateListener()
{
#Override
public void onAnimationUpdate(ValueAnimator animation)
{
int elapsedSeconds = (int) animation.getAnimatedValue();
int minutes = elapsedSeconds / 60;
int seconds = elapsedSeconds % 60;
textView.setText(String.format("%d:%02d", minutes, seconds));
}
});
timer.start();
For those who can't rely on Chronometer, I made a utility class out of one of the suggestions:
public class TimerTextHelper implements Runnable {
private final Handler handler = new Handler();
private final TextView textView;
private volatile long startTime;
private volatile long elapsedTime;
public TimerTextHelper(TextView textView) {
this.textView = textView;
}
#Override
public void run() {
long millis = System.currentTimeMillis() - startTime;
int seconds = (int) (millis / 1000);
int minutes = seconds / 60;
seconds = seconds % 60;
textView.setText(String.format("%d:%02d", minutes, seconds));
if (elapsedTime == -1) {
handler.postDelayed(this, 500);
}
}
public void start() {
this.startTime = System.currentTimeMillis();
this.elapsedTime = -1;
handler.post(this);
}
public void stop() {
this.elapsedTime = System.currentTimeMillis() - startTime;
handler.removeCallbacks(this);
}
public long getElapsedTime() {
return elapsedTime;
}
}
to use..just do:
TimerTextHelper timerTextHelper = new TimerTextHelper(textView);
timerTextHelper.start();
.....
timerTextHelper.stop();
long elapsedTime = timerTextHelper.getElapsedTime();
enter code here
Thread th=new Thread(new Runnable() {
#Override
public void run() {
try { for(int i=0;i<5;i++) {
b1.setText(""+i);
Thread.sleep(5000);
runOnUiThread(new Runnable() {
#Override
public void run() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
pp();
}
}
});
}} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
th.start();
Here is the solution for this you need to add the following class in your code. And you can directly add a view to your XML file.
import android.annotation.TargetApi;
import android.content.Context;
import android.os.Build;
import android.util.AttributeSet;
import android.view.View;
import android.widget.TextView;
import java.util.Locale;
import java.util.Timer;
import java.util.TimerTask;
import java.util.concurrent.TimeUnit;
public class TimerTextView extends TextView {
private static final int DEFAULT_INTERVAL = 1000;
private Timer timer = new Timer();
private long endTime = 0;
private long interval = DEFAULT_INTERVAL;
private boolean isCanceled = false;
public TimerTextView(Context context) {
super(context);
}
public TimerTextView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public TimerTextView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#TargetApi(Build.VERSION_CODES.LOLLIPOP)
public TimerTextView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
}
#Override protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
stopTimer();
}
#Override protected void onVisibilityChanged(View changedView, int visibility) {
super.onVisibilityChanged(changedView, visibility);
if (VISIBLE == visibility) {
startTimer();
} else {
stopTimer();
}
}
public void setInterval(long interval) {
if (interval >= 0) {
this.interval = interval;
stopTimer();
startTimer();
}
}
public void setEndTime(long endTime) {
if (endTime >= 0) {
this.endTime = endTime;
stopTimer();
startTimer();
}
}
private void startTimer() {
if (endTime == 0) {
return;
}
if (isCanceled) {
timer = new Timer();
isCanceled = false;
}
timer.scheduleAtFixedRate(new TimerTask() {
#Override public void run() {
if (null == getHandler()) {
return;
}
getHandler().post(new Runnable() {
#Override public void run() {
setText(getDurationBreakdown(endTime - System.currentTimeMillis()));
}
});
}
}, 0, interval);
}
private void stopTimer() {
timer.cancel();
isCanceled = true;
}
private String getDurationBreakdown(long diff) {
long millis = diff;
if (millis < 0) {
return "00:00:00";
}
long hours = TimeUnit.MILLISECONDS.toHours(millis);
millis -= TimeUnit.HOURS.toMillis(hours);
long minutes = TimeUnit.MILLISECONDS.toMinutes(millis);
millis -= TimeUnit.MINUTES.toMillis(minutes);
long seconds = TimeUnit.MILLISECONDS.toSeconds(millis);
return String.format(Locale.ENGLISH, "%02d:%02d:%02d", hours, minutes, seconds);
//return "${getWithLeadZero(hours)}:${getWithLeadZero(minutes)}:${getWithLeadZero(seconds)}"
}
}
You need to create a thread to handle the update loop and use it to update the textarea. The tricky part though is that only the main thread can actually modify the ui so the update loop thread needs to signal the main thread to do the update. This is done using a Handler.
Check out this link: http://developer.android.com/guide/topics/ui/dialogs.html#
Click on the section titled "Example ProgressDialog with a second thread". It's an example of exactly what you need to do, except with a progress dialog instead of a textfield.
void method(boolean u,int max)
{
uu=u;
maxi=max;
if (uu==true)
{
CountDownTimer uy = new CountDownTimer(maxi, 1000)
{
public void onFinish()
{
text.setText("Finish");
}
#Override
public void onTick(long l) {
String currentTimeString=DateFormat.getTimeInstance().format(new Date());
text.setText(currentTimeString);
}
}.start();
}
else{text.setText("Stop ");
}
If anyone is interested, I started playing around with creating a standard object to run on an activities UI thread. Seems to work ok. Comments welcome. I'd love this to be available on the layout designer as a component to drag onto an Activity. Can't believe something like that doesn't already exist.
package com.example.util.timer;
import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
public class ActivityTimer {
private Activity m_Activity;
private boolean m_Enabled;
private Timer m_Timer;
private long m_Delay;
private long m_Period;
private ActivityTimerListener m_Listener;
private ActivityTimer _self;
private boolean m_FireOnce;
public ActivityTimer() {
m_Delay = 0;
m_Period = 100;
m_Listener = null;
m_FireOnce = false;
_self = this;
}
public boolean isEnabled() {
return m_Enabled;
}
public void setEnabled(boolean enabled) {
if (m_Enabled == enabled)
return;
// Disable any existing timer before we enable a new one
Disable();
if (enabled) {
Enable();
}
}
private void Enable() {
if (m_Enabled)
return;
m_Enabled = true;
m_Timer = new Timer();
if (m_FireOnce) {
m_Timer.schedule(new TimerTask() {
#Override
public void run() {
OnTick();
}
}, m_Delay);
} else {
m_Timer.schedule(new TimerTask() {
#Override
public void run() {
OnTick();
}
}, m_Delay, m_Period);
}
}
private void Disable() {
if (!m_Enabled)
return;
m_Enabled = false;
if (m_Timer == null)
return;
m_Timer.cancel();
m_Timer.purge();
m_Timer = null;
}
private void OnTick() {
if (m_Activity != null && m_Listener != null) {
m_Activity.runOnUiThread(new Runnable() {
#Override
public void run() {
m_Listener.OnTimerTick(m_Activity, _self);
}
});
}
if (m_FireOnce)
Disable();
}
public long getDelay() {
return m_Delay;
}
public void setDelay(long delay) {
m_Delay = delay;
}
public long getPeriod() {
return m_Period;
}
public void setPeriod(long period) {
if (m_Period == period)
return;
m_Period = period;
}
public Activity getActivity() {
return m_Activity;
}
public void setActivity(Activity activity) {
if (m_Activity == activity)
return;
m_Activity = activity;
}
public ActivityTimerListener getActionListener() {
return m_Listener;
}
public void setActionListener(ActivityTimerListener listener) {
m_Listener = listener;
}
public void start() {
if (m_Enabled)
return;
Enable();
}
public boolean isFireOnlyOnce() {
return m_FireOnce;
}
public void setFireOnlyOnce(boolean fireOnce) {
m_FireOnce = fireOnce;
}
}
In the activity, I have this onStart:
#Override
protected void onStart() {
super.onStart();
m_Timer = new ActivityTimer();
m_Timer.setFireOnlyOnce(true);
m_Timer.setActivity(this);
m_Timer.setActionListener(this);
m_Timer.setDelay(3000);
m_Timer.start();
}
Here is a simple reliable way...
Put the following code in your Activity, and the tick() method will be called every second in the UI thread while your activity is in the "resumed" state. Of course, you can change the tick() method to do what you want, or to be called more or less frequently.
#Override
public void onPause() {
_handler = null;
super.onPause();
}
private Handler _handler;
#Override
public void onResume() {
super.onResume();
_handler = new Handler();
Runnable r = new Runnable() {
public void run() {
if (_handler == _h0) {
tick();
_handler.postDelayed(this, 1000);
}
}
private final Handler _h0 = _handler;
};
r.run();
}
private void tick() {
System.out.println("Tick " + System.currentTimeMillis());
}
For those interested, the "_h0=_handler" code is necessary to avoid two timers running simultaneously if your activity is paused and resumed within the tick period.
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Timer;
import java.util.TimerTask;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.TextView;
import android.app.Activity;
public class MainActivity extends Activity {
CheckBox optSingleShot;
Button btnStart, btnCancel;
TextView textCounter;
Timer timer;
MyTimerTask myTimerTask;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
optSingleShot = (CheckBox)findViewById(R.id.singleshot);
btnStart = (Button)findViewById(R.id.start);
btnCancel = (Button)findViewById(R.id.cancel);
textCounter = (TextView)findViewById(R.id.counter);
btnStart.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View arg0) {
if(timer != null){
timer.cancel();
}
//re-schedule timer here
//otherwise, IllegalStateException of
//"TimerTask is scheduled already"
//will be thrown
timer = new Timer();
myTimerTask = new MyTimerTask();
if(optSingleShot.isChecked()){
//singleshot delay 1000 ms
timer.schedule(myTimerTask, 1000);
}else{
//delay 1000ms, repeat in 5000ms
timer.schedule(myTimerTask, 1000, 5000);
}
}});
btnCancel.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v) {
if (timer!=null){
timer.cancel();
timer = null;
}
}
});
}
class MyTimerTask extends TimerTask {
#Override
public void run() {
Calendar calendar = Calendar.getInstance();
SimpleDateFormat simpleDateFormat =
new SimpleDateFormat("dd:MMMM:yyyy HH:mm:ss a");
final String strDate = simpleDateFormat.format(calendar.getTime());
runOnUiThread(new Runnable(){
#Override
public void run() {
textCounter.setText(strDate);
}});
}
}
}
.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:orientation="vertical"
tools:context=".MainActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:autoLink="web"
android:text="http://android-er.blogspot.com/"
android:textStyle="bold" />
<CheckBox
android:id="#+id/singleshot"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Single Shot"/>
If you have delta time already.
public class Timer {
private float lastFrameChanged;
private float frameDuration;
private Runnable r;
public Timer(float frameDuration, Runnable r) {
this.frameDuration = frameDuration;
this.lastFrameChanged = 0;
this.r = r;
}
public void update(float dt) {
lastFrameChanged += dt;
if (lastFrameChanged > frameDuration) {
lastFrameChanged = 0;
r.run();
}
}
}
I Abstract Timer away and made it a separate class:
Timer.java
import android.os.Handler;
public class Timer {
IAction action;
Handler timerHandler = new Handler();
int delayMS = 1000;
public Timer(IAction action, int delayMS) {
this.action = action;
this.delayMS = delayMS;
}
public Timer(IAction action) {
this(action, 1000);
}
public Timer() {
this(null);
}
Runnable timerRunnable = new Runnable() {
#Override
public void run() {
if (action != null)
action.Task();
timerHandler.postDelayed(this, delayMS);
}
};
public void start() {
timerHandler.postDelayed(timerRunnable, 0);
}
public void stop() {
timerHandler.removeCallbacks(timerRunnable);
}
}
And Extract main action from Timer class out as
IAction.java
public interface IAction {
void Task();
}
And I used it just like this:
MainActivity.java
public class MainActivity extends Activity implements IAction{
...
Timer timerClass;
#Override
protected void onCreate(Bundle savedInstanceState) {
...
timerClass = new Timer(this,1000);
timerClass.start();
...
}
...
int i = 1;
#Override
public void Task() {
runOnUiThread(new Runnable() {
#Override
public void run() {
timer.setText(i + "");
i++;
}
});
}
...
}
I Hope This Helps 😊👌
I use this way:
String[] array={
"man","for","think"
}; int j;
then below the onCreate
TextView t = findViewById(R.id.textView);
new CountDownTimer(5000,1000) {
#Override
public void onTick(long millisUntilFinished) {}
#Override
public void onFinish() {
t.setText("I "+array[j] +" You");
j++;
if(j== array.length-1) j=0;
start();
}
}.start();
it's easy way to solve this problem.