如何使用两个按钮实现多个日期选择器功能并保存选择的日期？

Question

我想创建一个活动，我想在其中有两个按钮和多个标签。用户可以单击按钮来选择从和到的日期。而那些选定的日期可以显示在标签中，以便用户可以知道用户已经选择了哪些日期。

谁能指导我如何做到这一点。

1. 使用多个日期选择器功能，两个按钮上只有两个日期选择器。
2. 如何保存这些日期。因此，每当用户离开此活动并再次访问时，他可能会知道。

Answer 1

我已经创建了DatePickerFragment 助手类，通过这个你可以选择任意数量的日期，只需要一个 DatePickerFragment 类。

public class DatePickerFragment extends DialogFragment implements DatePickerDialog.OnDateSetListener {

    /**
     * The callback interface used to indicate the user is done filling in the date (they clicked on the 'Set' button).
     */
    public interface OnDateSetListener {

        /**
         * @param dialog The view associated with this listener.
         * @param year The year that was set.
         * @param monthOfYear The monthOfYear that was set.
         * @param dayOfMonth The dayOfMonth that was set.
         */
        void onDateSet(DatePicker dialog, int year, int monthOfYear, int dayOfMonth, int reqCode);
    }

    private OnDateSetListener mListener;
    private int reqCode;
    public void setOnDateSetListener(OnDateSetListener mListener, int reqCode){
        this.mListener  = mListener;
        this.reqCode = reqCode;
    }

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {

        int year;
        int month;
        int day;
        final Calendar c = Calendar.getInstance();
        Bundle bundle = this.getArguments();
        if(bundle!=null) {
            // Use the given date as the default date in the picker
            year = bundle.getInt("YEAR");
            month = bundle.getInt("MONTH");
            day = bundle.getInt("DAY");
        }else{
            // Use the current date as the default date in the picker
            year = c.get(Calendar.YEAR);
            month = c.get(Calendar.MONTH);
            day = c.get(Calendar.DAY_OF_MONTH);
        }

        // Create a new instance of DatePickerDialog and return it
        return new DatePickerDialog(getActivity(), this, year, month, day);
    }

    @Override
    public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
        if(mListener!=null)
            mListener.onDateSet(view, year, monthOfYear, dayOfMonth, reqCode);
        this.dismiss();
    }
}

在Activity或Fragment中使用

public class MainActivity extends FragmentActivity implements DatePickerFragment.OnDateSetListener {
    private static final int FROM_DATE_TAG = 2404;
    private static final int TO_DATE_TAG = 2405;

    @Override
    public void onClick(View view) {
        FragmentManager fragmentManager = getSupportFragmentManager();
        DatePickerFragment fragment;
        switch(view.getId()){
        case R.id.fromDate:
            fragment = new DatePickerFragment();
            fragment.setOnDateSetListener(this, FROM_DATE_TAG);
            fragment.show(fragmentManager, "Date Picker");
            break;
        case R.id.toDate:
            fragment = new DatePickerFragment();
            fragment.setOnDateSetListener(this, TO_DATE_TAG);
            fragment.show(fragmentManager, "Date Picker");
            break;
        }
    }

    //If you want to update the alredy selected date, Specify it in budle. DatePickerFragment will take specified bundle date as default date.
    private void updateDate() {
        //get to date stored in SharedPrefrence
        String toDate = SharedPrefrenceUtils.getString(mContext, "FROM_DATE");
        SimpleDateFormat sdf = new SimpleDateFormat("MMM dd, yyyy", Locale.getDefault());
        Date parse = sdf.parse(toDate);
        Calendar c = Calendar.getInstance();
        c.setTime(parse);
        FragmentManager fragmentManager = this.getActivity().getSupportFragmentManager();
        DatePickerFragment fragment = new DatePickerFragment();
        Bundle bundle = new Bundle();
        bundle.putInt("YEAR", c.get(Calendar.YEAR));
        bundle.putInt("MONTH", c.get(Calendar.MONTH));
        bundle.putInt("DAY", c.get(Calendar.DATE));
        fragment.setArguments(bundle);
        fragment.setOnDateSetListener(this, FROM_DATE_TAG);
        fragment.show(fragmentManager, "Date Picker");
    }

    @Override
    public void onDateSet(DatePicker dialog, int year, int monthOfYear, int dayOfMonth, int reqCode) {
        if(reqCode == FROM_DATE_TAG){
            Calendar myCalendar  = Calendar.getInstance();
            myCalendar.set(year, monthOfYear, dayOfMonth);
            SimpleDateFormat formatter = new SimpleDateFormat("MMM dd, yyyy", Locale.getDefault());
            String dateString = formatter.format(myCalendar.getTime());
            Log.i("From Date","DATE:"+dateString);//"Result = DATE:May 24, 2015"
            //Store FROM_DATE in SharedPrefrence
            SharedPrefrenceUtils.putString(mContext,"FROM_DATE", dateString);
        } else if(reqCode == TO_DATE_TAG){
            Calendar myCalendar  = Calendar.getInstance();
            myCalendar.set(year, monthOfYear, dayOfMonth);
            SimpleDateFormat formatter = new SimpleDateFormat("MMM dd, yyyy", Locale.getDefault());
            String dateString = formatter.format(myCalendar.getTime());
            Log.i("To Date","DATE:"+dateString);//"Result = DATE:May 25, 2015"
            //Store TO_DATE in SharedPrefrence
            SharedPrefrenceUtils.putString(mContext,"TO_DATE", dateString);
        }
    }
}

请参阅 How to display SharedPreference stored data in Fragment? 了解 SharedPrefrenceUtils 类。

Answer 2

您可以使用共享首选项来存储最后一个日期选择器值。