SettingsActivity 应该扩展什么类？
对我有用的是扩展AppCompatActivity。
static final String ANIMATION = "animation" ;
static final String COUNTDOWN_ON_OFF = "countdown_on_off";
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
if (getFragmentManager().findFragmentById(android.R.id.content) == null)
{
getFragmentManager().beginTransaction().add(android.R.id.content, new Prefs()).commit();
}
}
我踢掉了所有与偏好标头相关的生成代码，并为我的PreferenceFragment保留了一些模板方法/变量（Android Studio 在某些早期版本中生成）
public static class Prefs extends PreferenceFragment
{
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.preferences);
// Bind the summaries of EditText/List/Dialog/Ringtone preferences
// to their values. When their values change, their summaries are
// updated to reflect the new value, per the Android Design
// guidelines.
// findPreference() uses android:key like in preferences.xml !
bindPreferenceSummaryToValue(findPreference(ANIMATION));
}
}
Activity 类中的静态方法（改编自模板）。您可能需要检查其他偏好类型：
/**
* Binds a preference's summary to its value. More specifically, when the
* preference's value is changed, its summary (line of text below the
* preference title) is updated to reflect the value. The summary is also
* immediately updated upon calling this method. The exact display format is
* dependent on the type of preference.
*
* @see #sBindPreferenceSummaryToValueListener
*/
private static void bindPreferenceSummaryToValue(Preference preference)
{
// Set the listener to watch for value changes.
preference.setOnPreferenceChangeListener(sBindPreferenceSummaryToValueListener);
// Trigger the listener immediately with the preference's
// current value.
if (preference instanceof CheckBoxPreference)
{
sBindPreferenceSummaryToValueListener.onPreferenceChange(preference,
PreferenceManager
.getDefaultSharedPreferences(preference.getContext())
.getBoolean(preference.getKey(), true));
}
else
{
sBindPreferenceSummaryToValueListener.onPreferenceChange(preference,
PreferenceManager
.getDefaultSharedPreferences(preference.getContext())
.getString(preference.getKey(), ""));
}
}
最后，Preference.OnPreferenceChangeListener 作为Activity 中的静态变量（也改编自模板）：
/**
* A preference value change listener that updates the preference's summary
* to reflect its new value.<br>
* template by Android Studio minus Ringtone Preference
*/
private static Preference.OnPreferenceChangeListener sBindPreferenceSummaryToValueListener = new Preference.OnPreferenceChangeListener()
{
@Override
public boolean onPreferenceChange(Preference preference, Object value)
{
String stringValue = value.toString();
if (preference instanceof ListPreference)
{
// For list preferences, look up the correct display value in
// the preference's 'entries' list.
ListPreference listPreference = (ListPreference) preference;
int index = listPreference.findIndexOfValue(stringValue);
// Set the summary to reflect the new value.
preference.setSummary(
index >= 0
? listPreference.getEntries()[index]
: null);
}
else if (preference instanceof RingtonePreference)
{
// my app didn't need that
return true;
}
else if (preference instanceof CheckBoxPreference)
{
Context ctx = preference.getContext();
boolean isChecked = (Boolean) value;
if (preference.getKey().equals(ANIMATION))
{
preference.setSummary(isChecked ? ctx.getString(R.string.sOn) : ctx.getString(R.string.sOff));
}
else if (preference.getKey().equals(COUNTDOWN_ON_OFF))
{
preference.setSummary(isChecked ? ctx.getString(R.string.sWhenPaused) : ctx.getString(R.string.sNever) );
}
}
else
{
// For all other preferences, set the summary to the value's
// simple string representation.
preference.setSummary(stringValue);
}
return true;
}
};
}