How do I get Interface Bundle to deliver previous date to DatePickerDialog?

问题

I have a DatePickerDialog that opens in a fragment. On first open, the dialog's default date displays today's date. The user then selects a date. When the dialog is dismissed, I set an EditText line with the user selected date.

The next time the dialog opens (because the user wants to edit their previously selected date), I want to show the user's previously selected date as the default date, not today's date. I've set up an interface from the fragment to the activity with a Bundle. Also, not sure my emptiness test on "year" in Fragment's OnCreateDialog is working properly. Please advise.

partial DatePickerFragment file:

public class DatePickerFragment extends DialogFragment implements DatePickerDialog.OnDateSetListener {

private int currentyear;
private int currentmonth;
private int currentday;

public DatePickerFragment() {
}

public interface OnDateEnteredListener {
     void OnDateEntered(int year, int month, int day);
}
OnDateEnteredListener mListener;


// Set up a Calendar object that will capture the current date for the DatePickerDialog to use.
Calendar cal = Calendar.getInstance();

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {

    final Bundle datebundle = this.getArguments();
    currentyear = datebundle.get(Calendar.YEAR);
    currentmonth = datebundle.get(Calendar.MONTH);
    currentday = datebundle.get(Calendar.DAY_OF_MONTH);

if(currentyear != 0){
        DatePickerDialog dateDialog = new DatePickerDialog(this.getActivity(), this, currentyear, currentmonth, currentday);
        dateDialog.getDatePicker().setCalendarViewShown(true);
        dateDialog.getDatePicker().setSpinnersShown(false);
        dateDialog.setTitle("Select a Due Date");
        return dateDialog;
    }
    else {
        // Create three variables to capture the current date.
        currentyear = cal.get(Calendar.YEAR);
        currentmonth = cal.get(Calendar.MONTH);
        currentday = cal.get(Calendar.DAY_OF_MONTH);
        // Create a DatePickerDialog which is a simple dialog containing a DatePicker.  Use the current date
        // as the default date in the DatePicker.  The new instance of DatePickerDialog is created by passing
        // 5 parameters/arguments to the constructor and returning it.
        DatePickerDialog dateDialog = new DatePickerDialog(this.getActivity(), this, currentyear, currentmonth, currentday);
        dateDialog.getDatePicker().setCalendarViewShown(true);
        dateDialog.getDatePicker().setSpinnersShown(false);
        dateDialog.setTitle("Select a Due Date");
        return dateDialog;
    }
}


public void onDateSet (DatePicker view,int year, int month, int day) {
     mListener.OnDateEntered(year,month,day);
...

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
}

partial Activity file:

public class Activity extends AppCompatActivity implements DatePickerFragment.OnDateEnteredListener {

  int currentyear;
  int currentmonth;
  int currentday;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.input);

    fListenerEditText = (ListenerEditText) findViewById(R.id.FEditText);

    fListenerEditText.setOnFocusChangeListener(new OnFocusChangeListener() {
        @Override
        public void onFocusChange(View v, boolean hasFocus) {
        if (hasFocus && (fListenerEditText.getText().length() == 0)) {
        DialogFragment newFragment = new DatePickerFragment();
        Bundle datebundle = new Bundle();
              datebundle.putInt("YEAR", currentyear);
              datebundle.putInt("MONTH", currentmonth);
              datebundle.putInt("DAY", currentday);
              newFragment.setArguments(datebundle);
              newFragment.show(getSupportFragmentManager(), "datePicker");
           }
        }
    });

  @Override
  public void onDateEntered(int year, int month, int day) {
    Toast toast = Toast.makeText(getApplicationContext(), "Test", Toast.LENGTH_LONG);
    toast.show();
    }
}

回答1:

1. If previous date not found, show the dialog along with today's date using cal.get()

2. User select the date,set the EditText to the date selected.

3. If previous date found, parse the text from EditText to date format, set it to current date using cal.set(), and display the dialog using cal.get()

You can check whether the EditText is empty using .matches() method.

For example,

if(txtDate.getText().toString().matches(""))
         // txtDate was empty

来源：https://stackoverflow.com/questions/32686320/how-do-i-get-interface-bundle-to-deliver-previous-date-to-datepickerdialog