java - 使用 PreferenceFragment 绑定(bind)自定义首选项

Question

嗨!

我有一个扩展 DialogPreference 的自定义首选项类。我需要将它与我的 PreferenceFragment 类绑定(bind)(我从这里得到它:http://stackoverflow.com/questions/5533078/timepicker-in-preferencescreen)。如何实现？我是否需要在我的 preferences.xml 布局文件中声明自定义 DialogPrefrence？

这是 DialogPreference 类:

public class TimePreference extends DialogPreference {
    private int lastHour=0;
    private int lastMinute=0;
    private TimePicker picker=null;

    public static int getHour(String time) {
        String[] pieces=time.split(":");

        return(Integer.parseInt(pieces[0]));
    }

    public static int getMinute(String time) {
        String[] pieces=time.split(":");

        return(Integer.parseInt(pieces[1]));
    }

    public TimePreference(Context ctxt) {
        this(ctxt, null);
    }

    public TimePreference(Context ctxt, AttributeSet attrs) {
        this(ctxt, attrs, 0);
    }

    public TimePreference(Context ctxt, AttributeSet attrs, int defStyle) {
        super(ctxt, attrs, defStyle);

        setPositiveButtonText("Set");
        setNegativeButtonText("Cancel");
    }

    @Override
    protected View onCreateDialogView() {
        picker=new TimePicker(getContext());

        return(picker);
    }

    @Override
    protected void onBindDialogView(View v) {
        super.onBindDialogView(v);

        picker.setCurrentHour(lastHour);
        picker.setCurrentMinute(lastMinute);
    }

    @Override
    protected void onDialogClosed(boolean positiveResult) {
        super.onDialogClosed(positiveResult);

        if (positiveResult) {
            lastHour=picker.getCurrentHour();
            lastMinute=picker.getCurrentMinute();

            String time=String.valueOf(lastHour)+":"+String.valueOf(lastMinute);

            if (callChangeListener(time)) {
                persistString(time);
            }
        }
    }

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

    @Override
    protected void onSetInitialValue(boolean restoreValue, Object defaultValue) {
        String time=null;

        if (restoreValue) {
            if (defaultValue==null) {
                time=getPersistedString("00:00");
            }
            else {
                time=getPersistedString(defaultValue.toString());
            }
        }
        else {
            time=defaultValue.toString();
        }

        lastHour=getHour(time);
        lastMinute=getMinute(time);
    }
}

非常感谢!

Answer 1

在首选项 fragment 中，您需要从预定义的 xml 加载首选项:

public static class MyPreferenceFragment extends PreferenceFragment {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Load the preferences from an XML resource
        addPreferencesFromResource(R.xml.preferences);
    }
}

在您的 preferences.xml 中使用自定义首选项对话框，如果它是自定义 View ，则以相同的方式:

<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >

    <com.example.TimePreference
        android:key="prefKey"
        android:defaultValue="00:00"
        android:summary="@string/pref_summary"
        android:title="@string/pref_title" />

</PreferenceScreen>