带有ViewPager的片段上的Android CountDownTimer

Question

I'm new on android development.

I've develop a ViewPager to show a different image when user click on next button.

But I want to start a CountDownTimer when the new image is displayed.

How can I do this?

My code is for the moment :

public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        int imgNumber = mPageNumber + 1;
        String strImg = "ss0" + imgNumber;
        ViewGroup rootView = (ViewGroup) inflater.inflate(
                R.layout.fragment_ssstretch4_split, container, false);

        // Set the title view to show the page number.
        ((TextView) rootView.findViewById(R.id.text1)).setText(
                getString(R.string.title_activity_ssstretch4_split, mPageNumber + 1));

        //Mettre l'image
        int idImg = getResources().getIdentifier("com.trainwithcoachminiil.app:drawable/" + strImg, null, null);
        ((ImageView) rootView.findViewById(R.id.imgSS)).setImageResource(idImg);

        //Lancer le timer
        textActivity = (TextView) rootView.findViewById(R.id.textActivity);
        textCountDown = (TextView) rootView.findViewById(R.id.textCountDown);
        countDownTimerPrepare = new CountDownTimerActivityPrepare(startTimePrepare, interval);
        textActivity.setText(R.string.activityPrepare);
        textCountDown.setText(String.valueOf(startTimePrepare/1000));
        countDownTimerPrepare.start();

        return rootView;
    }

But when I go to the next page my countdowntimer still running so I get strange behavior.

Thanks a lot if you could tell me how to do.

Answer 1

在Fragment onDestroy上调用yourCountDownTimer.cancel()

Answer 2

Viewpager loads atleast two pages/Fragment at a time. And it will start your second Fragment/page count timer .

So you should start timer when your fragment is visible . First handle fragment Visibility using setUserVisible or setMenuVisibility delegate's of Fragment. then start your countDown Timer. and cancel timer in on DestroyView