Reputation: 11
what I'm trying to do: My app connects with a Bluetooth accelerometer and gets acceleration data every 50ms. I want to check for these with a Runnable. And this worked fine. However, for the complete app I added two CountDownTimers:
1) introTimer(), which runs in an AlertDialog and counts down from 3. OnFinish() calls (i) my Runnable, that deals with new acceleration data and (ii) a second timer called
2) mainTimer(), which counts down from 20 and refreshes a TextView on the UI.
My problem is, that my Runnable is only executed once when it is first called. Why is that? Apparently I have not yet understood the threading principles behind this. My next step (probably going to be complicated) is to refresh ImageViews every 50ms (or maybe less often, but still with a relatively high frequency) on the UI, depending on the accelerometer data.
I have thought about deleting the Runnable and putting my calculations in the CountDownTimer, but this might be difficult or inaccurate with the timing/frequency/periods. What do you think?
Here are the code parts. If you think other parts are relevant, I can post them as well:
startButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
LayoutInflater layoutInflater = getActivity().getLayoutInflater();
View promptView = layoutInflater.inflate(R.layout.intro_timer_prompt, null);
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
final TextView introTimer = (TextView) promptView.findViewById(R.id.introTimer);
builder.setView(promptView);
AlertDialog alertD = builder.create();
alertD.show();
introTimer(introTimer, alertD);
}
private void introTimer(final TextView introTimer, final AlertDialog alertD) {
new CountDownTimer(4*1000, 1000) {
public void onTick(long millisUntilFinished) {
introTimer.setText( ""+ (millisUntilFinished / 1000));
}
public void onFinish() {
alertD.cancel();
// mainTimer();
clearArrayLists();
mHandler = new Handler();
mHandlerTask.run();
mainTimer();
}
}.start();
}
private void mainTimer() {
new CountDownTimer((int)DURATION*1000, 10) {
public void onTick(long millisUntilFinished) {
//mTimerView.setText("seconds remaining: " + millisUntilFinished / 1000 + ":" + millisUntilFinished / 1000. );
long millisecs = Math.round(millisUntilFinished % 1000 / 100);
mTimerView.setText("seconds remaining: " + millisUntilFinished / 1000 + ":" + millisecs );
}
public void onFinish() {
String energy = new DecimalFormat("#.##").format(accumulatedKineticEnergy.get(accumulatedKineticEnergy.size()-1));
mTimerView.setText("Accumulated Energy is " + energy + " Joule.");
}
}.start();
}
Runnable mHandlerTask = new Runnable() {
@Override
public void run() {
Log.i(TAG, "executed only once :( ");
if (a_x.size() < DURATION/INTERVAL) {
try {
calcAccList();
//...calc things...;
mHandler.postDelayed(this, (long) (1000*INTERVAL));
} catch (Exception e) {
e.getMessage();
}
}
else {
mHandler.removeCallbacks(mHandlerTask);
}
}
};
Upvotes: 1
Views: 809
Reputation: 22193
A countdown timer doesn't repeat itself when it expires, but you need to start it again. Maybe you can use the AlarmManager in this case to have a better design.
Upvotes: 0