PreferenceFragmentCompat 屏幕上的 DatePicker

Question

我用的是 unofficial PreferenceFragment compatibility layer for Android 1.6 and up. But Google has released v7 Preference Support Library。所以我的想法是迁移项目库。

当前实施： 在项目中我创建了一个自定义设置来支持 dates.

public class DatePreference extends DialogPreference implements DatePicker.OnDateChangedListener {

    private String dateString;
    private String changedValueCanBeNull;
    private DatePicker datePicker;
    private Calendar maxCalendar;
    private int maxYear;
    private int maxMonth;
    private int maxDay;

    public DatePreference(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    @Override
    protected View onCreateDialogView() {

        this.datePicker = new DatePicker(getContext());

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
           this.datePicker.setMaxDate(Calendar.getInstance().getTimeInMillis());
        } else {
            maxCalendar = Calendar.getInstance();
            maxYear = maxCalendar.get(Calendar.YEAR);
            maxMonth = maxCalendar.get(Calendar.MONTH);
            maxDay = maxCalendar.get(Calendar.DAY_OF_MONTH);
        }

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
            this.datePicker.setCalendarViewShown(false);
        }

        final Calendar calendar = getDate();
        datePicker.init(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH), calendar.get(Calendar.DAY_OF_MONTH),
                this);
        return datePicker;
    }

    public Calendar getDate() {
        try {
            final SimpleDateFormat sfd = formatter();
            final Date date = sfd.parse(defaultValue());
            final Calendar cal = Calendar.getInstance();
            cal.setTime(date);
            return cal;
        } catch (ParseException e) {
            return defaultCalendar();
        }
    }

    public void setDate(final String dateString) {
        this.dateString = dateString;
    }

    public static SimpleDateFormat formatter() {
        return new SimpleDateFormat("yyyy.MM.dd",    Locale.getDefault());
    }

    public static SimpleDateFormat summaryFormatter() {
        return new SimpleDateFormat("MMMM dd, yyyy",    Locale.getDefault());
    }

    @Override
    protected Object onGetDefaultValue(final TypedArray a, final int index) {
        return a.getString(index);
   }

    @Override
    protected void onSetInitialValue(final boolean restoreValue, final Object def) {
        if (restoreValue) {
            this.dateString = getPersistedString(defaultValue());
            setTheDate(this.dateString);
        } else {
            final boolean wasNull = this.dateString == null;
            setDate((String) def);
            if (!wasNull) {
                persistDate(this.dateString);
            }
        }
    }

    @Override
    protected Parcelable onSaveInstanceState() {
        if (isPersistent()) {
            return super.onSaveInstanceState();
        } else {
            return new SavedState(super.onSaveInstanceState());
        }
    }

    @Override
    protected void onRestoreInstanceState(final Parcelable state) {
        if (state == null || !state.getClass().equals(SavedState.class)) {
            super.onRestoreInstanceState(state);
            try {
                if (state != null) {
                    setTheDate(((SavedState) state).dateValue);
                }
            } catch (ClassCastException e) {
                  SiempreListoLogger.INSTANCE.error(DatePreference.class.getSimpleName(), "Error casting class to date preference " + Log.getStackTraceString(e));
            }
        } else {
            final SavedState s = (SavedState) state;
            super.onRestoreInstanceState(s.getSuperState());
            setTheDate(s.dateValue);
        }
    }

    @Override
    public void onDateChanged(final DatePicker view, final int year, final int month, final int day) {
        Calendar selected = new GregorianCalendar(year, month, day);
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB && selected.after(maxCalendar)) {
            selected = new GregorianCalendar(maxYear, maxMonth, maxDay);
        }
        this.changedValueCanBeNull = formatter().format(selected.getTime());

    }

    @Override
    protected void onDialogClosed(final boolean shouldSave) {
        if (shouldSave && this.changedValueCanBeNull != null) {
            setTheDate(this.changedValueCanBeNull);
            this.changedValueCanBeNull = null;
        }
    }

    private void setTheDate(final String s) {
        setDate(s);
        persistDate(s);
    }

    private void persistDate(final String s) {
        persistString(s);
        setSummary(summaryFormatter().format(getDate().getTime()));
    }

    public static Calendar defaultCalendar() {
        return new GregorianCalendar(1900, 0, 1);
    }

    public static String defaultCalendarString() {
        return formatter().format(defaultCalendar().getTime());
    }

    private String defaultValue() {
        if (this.dateString == null) {
            setDate(defaultCalendarString());
        }
        return this.dateString;
    }

    @Override
    public void onClick(final DialogInterface dialog, final int which)    {
        super.onClick(dialog, which);
        datePicker.clearFocus();
        onDateChanged(datePicker, datePicker.getYear(), datePicker.getMonth(), datePicker.getDayOfMonth());
        onDialogClosed(which == DialogInterface.BUTTON_POSITIVE); // OK?
    }

    private static class SavedState extends BaseSavedState {

        private transient String dateValue;

        @SuppressWarnings("unused")
        public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() {
            @Override
            public SavedState createFromParcel(final Parcel parcel) {
                return new SavedState(parcel);
            }

            @Override
            public SavedState[] newArray(final int size) {
                return new SavedState[size];
            }
        };

        public SavedState(final Parcel p) {
            super(p);
            dateValue = p.readString();
        }

        public SavedState(final Parcelable p) {
            super(p);
        }

        @Override
        public void writeToParcel(final Parcel parcel, final int flags) {
            super.writeToParcel(parcel, flags);
            parcel.writeString(dateValue);
        }

    }
}

为了支持这种偏好，我使用 DatePickerFragment 来允许用户 select 使用本机 DatePicker 的日期。

public class DatePickerFragment extends DialogFragment {

    public static final String TAG = DatePickerFragment.class.getName();

    private static final String MINIMUM_DATE_TO_SHOW = "minimum_date_to_show";

    private static final String DATE_TO_SHOW = "date_to_show";

    private DatePickerDialog.OnDateSetListener mListener;

    public static DatePickerFragment newInstance(DatePickerDialog.OnDateSetListener listener) {
        DatePickerFragment newInstance = new DatePickerFragment();
        newInstance.mListener = listener;
        return newInstance;
    }

    public static DatePickerFragment newInstance(DatePickerDialog.OnDateSetListener listener, Date date) {
        DatePickerFragment newInstance = new DatePickerFragment();
        Bundle args = new Bundle();
        args.putSerializable(MINIMUM_DATE_TO_SHOW, date);
        args.putSerializable(DATE_TO_SHOW, date);
        newInstance.setArguments(args);
        newInstance.mListener = listener;
        return newInstance;
    }

    @Override
    @NonNull
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        // Use the current date as the default date in the picker
        final Calendar c = Calendar.getInstance();
        int minimumYear = c.get(Calendar.YEAR);
        int minimumMonth = c.get(Calendar.MONTH);
        int minimumDay = c.get(Calendar.DAY_OF_MONTH);

        int year = c.get(Calendar.YEAR);
        int month = c.get(Calendar.MONTH);
        int day = c.get(Calendar.DAY_OF_MONTH);

        if (getArguments() != null &&    getArguments().containsKey(MINIMUM_DATE_TO_SHOW)) {
            Date date = (Date) getArguments().getSerializable(MINIMUM_DATE_TO_SHOW);
            if (date != null) {
                c.setTime(date);
                minimumYear = c.get(Calendar.YEAR);
                minimumMonth = c.get(Calendar.MONTH);
                minimumDay = c.get(Calendar.DAY_OF_MONTH);
            }
        }

        if (getArguments() != null &&    getArguments().containsKey(DATE_TO_SHOW)) {
            Date date = (Date) getArguments().getSerializable(DATE_TO_SHOW);
            if (date != null) {
                c.setTime(date);
                year = c.get(Calendar.YEAR);
                month = c.get(Calendar.MONTH);
                day = c.get(Calendar.DAY_OF_MONTH);
            }
        }

        final Date minimumDate = Utils.getDateFromValues(minimumYear, minimumMonth, minimumDay);

        // Create a new instance of DatePickerDialog and return it
        final DatePickerDialog datePickerDialog = new DatePickerDialog(getActivity(), mListener, year, month, day);
        datePickerDialog.setButton(DialogInterface.BUTTON_POSITIVE, getString(android.R.string.ok), new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                DatePicker datePicker = datePickerDialog.getDatePicker();
                datePicker.setMinDate(minimumDate.getTime());
                mListener.onDateSet(datePicker, datePicker.getYear(), datePicker.getMonth(), datePicker.getDayOfMonth());
            }
        });

        datePickerDialog.setButton(DialogInterface.BUTTON_NEGATIVE, getString(android.R.string.cancel), new DialogInterface.OnClickListener()    {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                DatePickerFragment.this.dismiss();
            }
        });
        return datePickerDialog;
    }

}

和settings.xml:

<PreferenceCategory
    android:layout="@layout/preference_activity_bg"
    android:title="@string/pref_user_private_info">

    <com.company.project.util.DatePreference
        android:defaultValue="1980.01.01"
        android:icon="@drawable/ic_birthdate"
        android:key="prefBirthdate"
        android:title="@string/pref_user_birthdate"/>

    <Preference
        android:icon="@drawable/ic_email"
        android:key="prefEmail"
        android:summary="@string/pref_user_email"
        android:title="@string/pref_user_email"/>

    <EditTextPreference
        android:icon="@drawable/ic_ic_telefono"
        android:inputType="phone"
        android:key="prefTel"
        android:maxLength="10"
        android:summary="@string/pref_user_phone"
        android:title="@string/pref_user_phone"/>

    <Preference
        android:icon="@drawable/ic_points"
        android:key="prefBalance"
        android:title="@string/pref_user_points"/>
</PreferenceCategory>

问题： 问题是 onCreateDialogView 和 onDialogClosed 在 v7 支持中找不到 DialogPreference.

编辑： 我发现 v7 PreferenceDialogFragmentCompat 应该与 v7 DialogPreference.

一起使用

Answer 1

v7 PreferenceDialogFragmentCompat 应与 v7 DialogPreference 结合使用。所以使用这个 response 代码可以用这种方式重构。

已修改 DatePrefence class:

public class DatePreference extends DialogPreference {

    private final String TAG = getClass().getSimpleName();

    public String dateString;

    public DatePreference(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public static String dateToString(Calendar calendar) {
        return summaryFormatter().format(calendar.getTime());
    }

    @Override
    protected Object onGetDefaultValue(TypedArray a, int index) {
        return a.getString(index);
    }

    @Override
    protected void onSetInitialValue(boolean restorePersistedValue, Object defaultValue) {
        if (restorePersistedValue) {
            if (defaultValue == null) dateString = getPersistedString(defaultValue());
            else dateString = getPersistedString(defaultValue.toString());
            setTheDate(dateString);
        } else {
            final boolean wasNull = dateString == null;
            setDate((String) defaultValue);
            if (!wasNull) {
                persistStringValue(dateString);
            }
        }
    }

    @Override
    protected Parcelable onSaveInstanceState() {
        if (isPersistent()) {
            return super.onSaveInstanceState();
        } else {
            return new SavedState(super.onSaveInstanceState());
        }
    }

    @Override
    protected void onRestoreInstanceState(Parcelable state) {
        if (state == null || !state.getClass().equals(SavedState.class)) {
            super.onRestoreInstanceState(state);
            try {
                if (state != null) {
                    setTheDate(((SavedState) state).dateValue);
                }
            } catch (ClassCastException e) {
                SiempreListoLogger.INSTANCE.error(TAG, "Error casting class to date preference " + Log.getStackTraceString(e));
            }
        } else {
            SavedState s = (SavedState) state;
            super.onRestoreInstanceState(s.getSuperState());
            setTheDate(s.dateValue);
        }
    }

    private String defaultValue() {
        if (this.dateString == null) {
            setDate(defaultCalendarString());
        }
        return this.dateString;
    }

    public static String defaultCalendarString() {
        return formatter().format(defaultCalendar().getTime());
    }

    public static SimpleDateFormat formatter() {
        return new SimpleDateFormat("yyyy.MM.dd", Locale.getDefault());
    }

    public static SimpleDateFormat summaryFormatter() {
        return new SimpleDateFormat("MMMM dd, yyyy", Locale.getDefault());
    }

    public static Calendar defaultCalendar() {
        return new GregorianCalendar(1900, 0, 1);
    }

    public void setTheDate(String s) {
        setDate(s);
        persistStringValue(s);
    }

    public void persistStringValue(String value) {
        persistString(value);
        setSummary(summaryFormatter().format(getDate().getTime()));
    }

    public void setDate(String dateString) {
        this.dateString = dateString;
    }

    public Calendar getDate() {
        try {
            final SimpleDateFormat sfd = formatter();
            final Date date = sfd.parse(defaultValue());
            final Calendar cal = Calendar.getInstance();
            cal.setTime(date);
            return cal;
        } catch (ParseException e) {
            return defaultCalendar();
        }
    }

    private static class SavedState extends Preference.BaseSavedState {

        private transient String dateValue;

        @SuppressWarnings("unused")
        public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() {
            @Override
            public SavedState createFromParcel(final Parcel parcel) {
                return new SavedState(parcel);
            }

            @Override
            public SavedState[] newArray(final int size) {
                return new SavedState[size];
            }
        };

        public SavedState(final Parcel p) {
            super(p);
            dateValue = p.readString();
        }

        public SavedState(final Parcelable p) {
            super(p);
        }

        @Override
        public void writeToParcel(final Parcel parcel, final int flags) {
            super.writeToParcel(parcel, flags);
            parcel.writeString(dateValue);
        }

    }

}

新建 DatePreferenceDialogFragmentCompat class:

public class DatePreferenceDialogFragmentCompat extends PreferenceDialogFragmentCompat implements DialogPreference.TargetFragment, DatePicker.OnDateChangedListener {

    DatePicker datePicker = null;
    private String changedValueCanBeNull;
    private Calendar maxCalendar;
    private int maxYear;
    private int maxMonth;
    private int maxDay;

    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    @Override
    protected View onCreateDialogView(Context context) {
        datePicker = new DatePicker(context);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
            datePicker.setMaxDate(Calendar.getInstance().getTimeInMillis());
        } else {
            maxCalendar = Calendar.getInstance();
            maxYear = maxCalendar.get(Calendar.YEAR);
            maxMonth = maxCalendar.get(Calendar.MONTH);
            maxDay = maxCalendar.get(Calendar.DAY_OF_MONTH);
        }

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
            this.datePicker.setCalendarViewShown(false);
        }

        DatePreference pref = (DatePreference) getPreference();
        Calendar calendar = pref.getDate();
        datePicker.init(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH), calendar.get(Calendar.DAY_OF_MONTH), this);
        return datePicker;
    }

    @Override
    protected void onBindDialogView(View view) {
        super.onBindDialogView(view);
        DatePreference pref = (DatePreference) getPreference();
        String value = DatePreference.dateToString(pref.getDate());
        if (pref.callChangeListener(value)) pref.persistStringValue(value);
    }

    @Override
    public void onDialogClosed(boolean positiveResult) {
        if (positiveResult && changedValueCanBeNull != null) {
            DatePreference pref = (DatePreference) getPreference();
            pref.setTheDate(changedValueCanBeNull);
            changedValueCanBeNull = null;
        }
    }

    @Override
    public void onClick(DialogInterface dialog, int which) {
        super.onClick(dialog, which);
        datePicker.clearFocus();
        onDateChanged(datePicker, datePicker.getYear(), datePicker.getMonth(), datePicker.getDayOfMonth());
        onDialogClosed(which == DialogInterface.BUTTON_POSITIVE); // OK?
    }

    @Override
    public Preference findPreference(CharSequence charSequence) {
        return getPreference();
    }

    @Override
    public void onDateChanged(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
        Calendar selected = new GregorianCalendar(year, monthOfYear, dayOfMonth);
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB && selected.after(maxCalendar)) {
            selected = new GregorianCalendar(maxYear, maxMonth, maxDay);
        }
        changedValueCanBeNull = DatePreference.formatter().format(selected.getTime());
    }
}

我还在 SettingsFragment 中添加了以下代码，它扩展了 PreferenceFragmentCompat:

@Override
public void onDisplayPreferenceDialog(Preference preference) {
    DialogFragment dialogFragment = null;
    if (preference instanceof DatePreference) {
        dialogFragment = new DatePreferenceDialogFragmentCompat();
        Bundle bundle = new Bundle(1);
        bundle.putString("key", preference.getKey());
        dialogFragment.setArguments(bundle);
    }

    if (dialogFragment != null) {
        dialogFragment.setTargetFragment(this, 0);
        dialogFragment.show(this.getFragmentManager(), "android.support.v7.preference.PreferenceFragment.DIALOG");
    } else {
        super.onDisplayPreferenceDialog(preference);
    }
}

PreferenceFragmentCompat 屏幕上的 DatePicker

DatePicker on PreferenceFragmentCompat screen

android

android-layout

android-preferences

android-datepicker