我正在創(chuàng)建一個具有兩個日期選擇器的應(yīng)用程序，以設(shè)置開始日期和結(jié)束日期。當(dāng)從對話框碎片中調(diào)用 DatePrper 時，我設(shè)置了兩個標(biāo)記來區(qū)分主活動中的結(jié)果： @Override public void onClick(View v) { switch (v.getId()) { case R.id.sel_start_date: DialogFragment startDatePicker = new DatePickerFragment(); startDatePicker.show(getSupportFragmentManager(), START_DATE_PICKER_TAG); break; case R.id.sel_end_date: DialogFragment endDatePicker = new DatePickerFragment(); endDatePicker.show(getSupportFragmentManager(), END_DATE_PICKER_TAG); break;日期拾取器碎片類：public class DatePickerFragment extends DialogFragment { @NonNull @Override public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) { Calendar calendar = Calendar.getInstance(); int year = calendar.get(Calendar.YEAR); int month = calendar.get(Calendar.MONTH); int day = calendar.get(Calendar.DAY_OF_MONTH); return new DatePickerDialog(getActivity(), (DatePickerDialog.OnDateSetListener) getActivity(), year, month, day ); }這就是我在主要活動中獲得結(jié)果的方式 @Override public void onDateSet(DatePicker view, int year, int month, int dayOfMonth) { if (view.getTag().equals(START_DATE_PICKER_TAG)) { calendarStartDate.set(Calendar.YEAR, year); calendarStartDate.set(Calendar.MONTH, month); calendarStartDate.set(Calendar.DAY_OF_MONTH, dayOfMonth); start_date_btn.setText(dayOfMonth + "/" + (month + 1) + "/" + year); } else { calendarEndDate.set(Calendar.YEAR, year); calendarEndDate.set(Calendar.MONTH, month); calendarEndDate.set(Calendar.DAY_OF_MONTH, dayOfMonth); end_date_btn.setText(dayOfMonth + "/" + (month + 1) + "/" + year); } }但是，我得到了一個空點例外做視圖.getTag（）。我該如何解決這個問題，或者我該如何區(qū)分結(jié)果？分類：日期拾取者對話是一個本機類，不是我創(chuàng)建的類，所以我無法編輯他們的方法
3 回答
UYOU
TA貢獻(xiàn)1878條經(jīng)驗 獲得超4個贊
溶液：定義兩個接口以將數(shù)據(jù)從片段轉(zhuǎn)發(fā)到活動。
步驟 1.定義要在 和 之間進(jìn)行通信的接口。OnDateSetListenerMainActivityDatePickerFragment
public interface OnDateSetListener {
void onDateSet(String tag, DatePicker view, int year, int month, int dayOfMonth);
}
步驟2.定義要在 和 之間進(jìn)行通信的接口。OnTimeSetListenerMainActivityTimePickerFragment
public interface OnTimeSetListener {
void onTimeSet(String tag, TimePicker view, int hourOfDay, int minute);
}
第3步.讓我們實現(xiàn)這兩個接口。MainActivity
public class MainActivity extends AppCompatActivity implements OnDateSetListener, OnTimeSetListener {
// Your code her
...
@Override
public void onDateSet(String tag, DatePicker view, int year, int month, int dayOfMonth) {
// Process code with tag here
}
@Override
public void onTimeSet(String tag, TimePicker view, int hourOfDay, int minute) {
// Process code with tag here.
}
}
步驟 4.更改代碼DatePickerFragment
public class DatePickerFragment extends DialogFragment implements DatePickerDialog.OnDateSetListener {
private static final String ARGUMENT_TAG = "ARGUMENT_TAG";
public static DatePickerFragment newInstance(String tag) {
Bundle args = new Bundle();
args.putString(ARGUMENT_TAG, tag);
DatePickerFragment fragment = new DatePickerFragment();
fragment.setArguments(args);
return fragment;
}
@NonNull
@Override
public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
Calendar calendar = Calendar.getInstance();
int year = calendar.get(Calendar.YEAR);
int month = calendar.get(Calendar.MONTH);
int day = calendar.get(Calendar.DAY_OF_MONTH);
return new DatePickerDialog(requireActivity(), this, year, month, day);
}
@Override
public void onDateSet(DatePicker view, int year, int month, int dayOfMonth) {
final String tag = getArguments().getString(ARGUMENT_TAG);
OnDateSetListener listener = (OnDateSetListener) requireActivity();
listener.onDateSet(tag, view, year, month, dayOfMonth);
}
}
第5步.在 中更改代碼。TimePickerFragment
public class TimePickerFragment extends DialogFragment implements TimePickerDialog.OnTimeSetListener {
private static final String ARGS_TAG = "ARGS_TAG";
public static TimePickerFragment newInstance(String tag) {
Bundle args = new Bundle();
args.putString(ARGS_TAG, tag);
TimePickerFragment fragment = new TimePickerFragment();
fragment.setArguments(args);
return fragment;
}
@Override
public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
Calendar calendar = Calendar.getInstance();
int hour = calendar.get(Calendar.HOUR_OF_DAY);
int minute = calendar.get(Calendar.MINUTE);
return new TimePickerDialog(requireActivity(), this, hour, minute, DateFormat.is24HourFormat(getActivity()));
}
@Override
public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
final String tag = getArguments().getString(ARGS_TAG);
OnTimeSetListener listener = (OnTimeSetListener) requireActivity();
listener.onTimeSet(tag, view, hourOfDay, minute);
}
}
狐的傳說
TA貢獻(xiàn)1804條經(jīng)驗 獲得超3個贊
正如我所看到的，您已經(jīng)將標(biāo)記設(shè)置為片段，但您嘗試獲取的是視圖的標(biāo)記。它們不是一回事，因為視圖的標(biāo)記是對象，而片段的標(biāo)記是字符串。
富國滬深
TA貢獻(xiàn)1790條經(jīng)驗 獲得超9個贊
正如您在 onDateSet 中看到的視圖是一個日期選取器，并且您在包含日期選取器的片段上設(shè)置了標(biāo)記，即日期選取器對話框。
因此，要獲得標(biāo)簽，您應(yīng)該嘗試以下操作：
@Override
public void onDateSet(DatePicker view, int year, int month, int dayOfMonth) {
if (view.getParent() != null && view.getParent().getTag().equals(START_DATE_PICKER_TAG)) {
calendarStartDate.set(Calendar.YEAR, year);
calendarStartDate.set(Calendar.MONTH, month);
calendarStartDate.set(Calendar.DAY_OF_MONTH, dayOfMonth);
start_date_btn.setText(dayOfMonth + "/" + (month + 1) + "/" + year);
} else {
calendarEndDate.set(Calendar.YEAR, year);
calendarEndDate.set(Calendar.MONTH, month);
calendarEndDate.set(Calendar.DAY_OF_MONTH, dayOfMonth);
end_date_btn.setText(dayOfMonth + "/" + (month + 1) + "/" + year);
}
}
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