EditTextPreference:

public class MyEditTextPreference extends EditTextPreference {
    public MyEditTextPreference(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

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

    @Override
    public void setText(String text) {
        super.setText(text);
        setSummary(text);
    }
}

如果适合您的需求，有一些方法可以使其成为更通用的解决方案。

例如，如果你想让所有的列表首选项显示为摘要，你可以为你的onSharedPreferenceChanged实现:

public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
    Preference pref = findPreference(key);

    if (pref instanceof ListPreference) {
        ListPreference listPref = (ListPreference) pref;
        pref.setSummary(listPref.getEntry());
    }
}

这很容易扩展到其他首选项类。

通过使用PreferenceScreen和PreferenceCategory中的getPreferenceCount和getPreference功能，您可以轻松地编写一个泛型函数来遍历首选项树，设置所需类型的所有首选项的摘要到它们的toString表示

FYI:

findPreference(CharSequence key)
This method was deprecated in API level 11. This function is not relevant
for a modern fragment-based PreferenceActivity.

更有理由看看上面@ASD的非常圆滑的答案(来源在这里找到)，它说在android:summary中对preferences.xml中的每个字段使用%s。(首选项的当前值替换为%s。)

<ListPreference
 ...        
 android:summary="Length of longest word to return as match is %s"
 ...
 />

在我花了几个小时来解决这样的问题后，我实现了以下代码:

[更新:最终版本列表]

public class MyPreferencesActivity extends PreferenceActivity {
    ...
    ListPreference m_updateList;
    ...
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.preferences);

        m_updateList = (ListPreference) findPreference(getString(R.string.pref_update_interval_key));
        String currentValue = m_updateList.getValue();
        if (currentValue == null) {
            m_updateList.setValue((String)m_updateList.getEntryValues()[DEFAULT_UPDATE_TIME_INDEX]);
            currentValue = m_updateList.getValue();
        }
        updateListSummary(currentValue);    

        m_updateList.setOnPreferenceChangeListener(new OnPreferenceChangeListener() {
            @Override
            public boolean onPreferenceChange(Preference preference, Object newValue) {
                updateListSummary(newValue.toString());
                return true;
            }       
        });     
    }

    private void updateListSummary(String newValue) {
        int index = m_updateList.findIndexOfValue(newValue);
        CharSequence entry = m_updateList.getEntries()[index];
        m_updateList.setSummary(entry);
    }
}

这是唯一对我有效的解决方法。在我尝试子类从ListPreferences和实现android:summary="bla bla bla %s"。既不工作。

我发现这种方法使EditTextPreference从支持库句柄“%s”在总结(因为ListPreference已经处理):

public class EditTextPreference extends android.support.v7.preference.EditTextPreference {
    public EditTextPreference(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    public void setText(String text) {
        super.setText(text);
        notifyChanged();
    }

    @Override
    public CharSequence getSummary() {
        String text = super.getText();
        String summary = super.getSummary().toString();
        return String.format(summary, text == null ? "" : text);
    }
}

在xml中它看起来是这样的:

<com.example.yourapp.EditTextPreference
    android:defaultValue="1"
    android:key="cleanup_period"
    android:summary="Clean up messages after %s days"
    android:title="Clean up period" />

因为我使用了一个自定义PreferenceDataStore，我不能添加一个监听器到一些SharedPreference，所以我不得不写一个有点hack的解决方案，监听每个偏好:

class SettingsFragment : PreferenceFragmentCompat(), Preference.OnPreferenceChangeListener {
    private val handler: Handler by lazy { Handler(Looper.getMainLooper()) }

    override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
        preferenceManager.preferenceDataStore = prefs
        addPreferencesFromResource(R.xml.app_preferences)
        onPreferenceChange(preferenceScreen, null)
    }

    override fun onPreferenceChange(preference: Preference, newValue: Any?): Boolean {
        preference.onPreferenceChangeListener = this

        when (preference) {
            is PreferenceGroup -> for (i in 0 until preference.preferenceCount) {
                onPreferenceChange(preference.getPreference(i), null)
            }
            is ListPreference -> {
                if (preference.value == null) {
                    preference.isPersistent = false
                    preference.value = Preference::class.java.getDeclaredField("mDefaultValue")
                            .apply { isAccessible = true }
                            .get(preference).toString()
                    preference.isPersistent = true
                }

                postPreferenceUpdate(Runnable { preference.summary = preference.entry })
            }
        }
        return true
    }

    /**
     * We can't directly update the preference summary update because [onPreferenceChange]'s result
     * is used to decide whether or not to update the pref value.
     */
    private fun postPreferenceUpdate(r: Runnable) = handler.post(r)
}