我正在使用线程，当我离开片段时，应用程序关闭

Question

我在片段中使用一个线程来更新在TextView中显示的时间。 但是，当我更改片段时，我的应用程序将关闭。 我相信在我离开该片段后，该线程将继续运行。 我试图在方法onPause()和onDestroy()使用Thread.interrupt() ，但我无法解决。

fragmentTime.java（没有Thread.interrupt() ）

public class EventosFragment extends Fragment {

    TextView currentTime;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View v = inflater.inflate(R.layout.fragment_eventos, container, false);

        currentTime = (TextView) v.findViewById(R.id.currentTime);

        Thread timer = new Thread() {
            @Override
            public void run() {
                try {
                    while (!isInterrupted()) {
                        Thread.sleep(1000);
                        getActivity().runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                updateTime();
                            }
                        });
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        };
        timer.start();

        return v;
    }

    public void updateTime() {
        Calendar c = Calendar.getInstance();
        int hours = c.get(Calendar.HOUR_OF_DAY);
        int minutes = c.get(Calendar.MINUTE);
        int seconds = c.get(Calendar.SECOND);
        SimpleDateFormat sourceFormat = new SimpleDateFormat("HH:mm:ss");
        sourceFormat.setTimeZone(TimeZone.getDefault());
        Date parsed = null; // => Date is in UTC now
        try {
            parsed = sourceFormat.parse(hours+":"+minutes+":"+seconds);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        currentTime.setText(sourceFormat.format(parsed));
    }

}

fragmentTime.java（带有Thread.interrupt() ）

public class EventosFragment extends Fragment {

    TextView currentTime;
    Thread timer;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View v = inflater.inflate(R.layout.fragment_eventos, container, false);

        currentTime = (TextView) v.findViewById(R.id.currentTime);

        timer = new Thread() {
            @Override
            public void run() {
                try {
                    while (!isInterrupted()) {
                        Thread.sleep(1000);
                        getActivity().runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                updateTime();
                            }
                        });
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        };
        timer.start();

        return v;
    }

    @Override
    public void onDestroy() {
        timer.interrupt();
        super.onDestroy();
    }
    @Override
    public void onResume() {
        timer.start();
        super.onResume();
    }
    @Override
    public void onPause() {
        timer.interrupt();
        super.onPause();
    }

    public void updateTime() {
        Calendar c = Calendar.getInstance();
        int hours = c.get(Calendar.HOUR_OF_DAY);
        int minutes = c.get(Calendar.MINUTE);
        int seconds = c.get(Calendar.SECOND);
        SimpleDateFormat sourceFormat = new SimpleDateFormat("HH:mm:ss");
        sourceFormat.setTimeZone(TimeZone.getDefault());
        Date parsed = null; // => Date is in UTC now
        try {
            parsed = sourceFormat.parse(hours+":"+minutes+":"+seconds);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        currentTime.setText(sourceFormat.format(parsed));
    }

}

Answer 1

getActivity返回null因为Fragment不再附加到Activity。

您可以通过在Fragment.onDetach停止计时器来解决此问题。