我已经看到了所有投票的答案，展示了如何用准确的当前值设置摘要，但OP也想要这样的东西:

“x天后清理消息”* <- summary，其中x是当前首选项值

以下是我实现这一目标的答案

根据ListPreference.getSummary()上的文档:

返回此ListPreference的摘要。如果摘要中有一个字符串格式标记(即。“%s”或“%1$s”)，然后是当前值 输入值将被替换在其位置上。

然而，我在几台设备上尝试了这一功能，似乎不起作用。通过一些研究，我在这个答案中找到了一个很好的解决方案。它简单地由扩展你使用的每个Preference和覆盖getSummary()组成，以按照Android文档指定的方式工作。

谢谢Reto的详细解释!

为了对大家有所帮助，我不得不修改Reto Meier提出的代码，使其与Android 1.5的SDK兼容

@Override
protected void onResume() {
    super.onResume();

    // Setup the initial values
    mListPreference.setSummary("Current value is " + mListPreference.getEntry().toString()); 

    // Set up a listener whenever a key changes            
    ...
}

同样的变化适用于回调函数onSharedPreferenceChanged(SharedPreferences SharedPreferences, String key)

欢呼,

克里斯

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"
 ...
 />

以下是我的解决方案:

构建一个首选项类型“getter”方法。

protected String getPreference(Preference x) {
    // http://stackoverflow.com/questions/3993982/how-to-check-type-of-variable-in-java
    if (x instanceof CheckBoxPreference)
        return "CheckBoxPreference";
    else if (x instanceof EditTextPreference)
        return "EditTextPreference";
    else if (x instanceof ListPreference)
        return "ListPreference";
    else if (x instanceof MultiSelectListPreference)
        return "MultiSelectListPreference";
    else if (x instanceof RingtonePreference)
        return "RingtonePreference";
    else if (x instanceof SwitchPreference)
        return "SwitchPreference";
    else if (x instanceof TwoStatePreference)
        return "TwoStatePreference";
    else if (x instanceof DialogPreference) // Needs to be after ListPreference
        return "DialogPreference";
    else
        return "undefined";
}

构建一个'setSummaryInit'方法。

public void onSharedPreferenceChanged(SharedPreferences prefs, String key) {
        Log.i(TAG, "+ onSharedPreferenceChanged(prefs:" + prefs + ", key:" + key + ")");
        if( key != null ) {
            updatePreference(prefs, key);
            setSummary(key);
        } else {
            Log.e(TAG, "Preference without key!");
        }
        Log.i(TAG, "- onSharedPreferenceChanged()");
    }

    protected boolean setSummary() {
        return _setSummary(null);
    }
    
    protected boolean setSummary(String sKey) {
        return _setSummary(sKey);
    }
    
    private boolean _setSummary(String sKey) {
        if (sKey == null) Log.i(TAG, "Initializing");
        else Log.i(TAG, sKey);
        
        // Get Preferences
        SharedPreferences sharedPrefs = PreferenceManager
                .getDefaultSharedPreferences(this);

        // Iterate through all Shared Preferences
        // http://stackoverflow.com/questions/9310479/how-to-iterate-through-all-keys-of-shared-preferences
        Map<String, ?> keys = sharedPrefs.getAll();
        for (Map.Entry<String, ?> entry : keys.entrySet()) {
            String key = entry.getKey();
            // Do work only if initializing (null) or updating specific preference key
            if ( (sKey == null) || (sKey.equals(key)) ) {
                String value = entry.getValue().toString();
                Preference pref = findPreference(key);
                String preference = getPreference(pref);
                Log.d("map values", key + " | " + value + " | " + preference);
                pref.setSummary(key + " | " + value + " | " + preference);
                if (sKey != null) return true;
            }
        }
        return false;
    }

    private void updatePreference(SharedPreferences prefs, String key) {
        Log.i(TAG, "+ updatePreference(prefs:" + prefs + ", key:" + key + ")");
        Preference pref = findPreference(key);
        String preferenceType = getPreference(pref);
        Log.i(TAG, "preferenceType = " + preferenceType);
        Log.i(TAG, "- updatePreference()");
    }

初始化

创建一个公共类PreferenceActivity并实现OnSharedPreferenceChangeListener

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    PreferenceManager.setDefaultValues(this, R.xml.global_preferences,
    false);
    this.addPreferencesFromResource(R.xml.global_preferences);
    this.getPreferenceScreen().getSharedPreferences()
        .registerOnSharedPreferenceChangeListener(this);
}

protected void onResume() {
    super.onResume();
    setSummary();
}

简洁的解决方案只需一行代码:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    addPreferencesFromResource(R.xml.preferences);

    bindPreferenceSummaryToValue(findPreference("mySetting"));

    // initialize summary
    sBindPreferenceSummaryToValueListener.onPreferenceChange(findPreference("mySetting"), 
        ((ListPreference) findPreference("mySetting")).getEntry());
}

由于在androidx首选项类有SummaryProvider接口，它可以在没有OnSharedPreferenceChangeListener的情况下完成。为EditTextPreference和ListPreference提供了简单的实现。根据EddieB的答案，它看起来像这样。在androidx.preference上测试:preference:1.1.0-alpha03。

package com.example.util.timereminder.ui.prefs;

import android.os.Bundle;

import com.example.util.timereminder.R;

import androidx.preference.EditTextPreference;
import androidx.preference.ListPreference;
import androidx.preference.Preference;
import androidx.preference.PreferenceFragmentCompat;
import androidx.preference.PreferenceGroup;

/**
 * Displays different preferences.
 */
public class PrefsFragmentExample extends PreferenceFragmentCompat {

    @Override
    public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
        addPreferencesFromResource(R.xml.preferences);

        initSummary(getPreferenceScreen());
    }

    /**
     * Walks through all preferences.
     *
     * @param p The starting preference to search from.
     */
    private void initSummary(Preference p) {
        if (p instanceof PreferenceGroup) {
            PreferenceGroup pGrp = (PreferenceGroup) p;
            for (int i = 0; i < pGrp.getPreferenceCount(); i++) {
                initSummary(pGrp.getPreference(i));
            }
        } else {
            setPreferenceSummary(p);
        }
    }

    /**
     * Sets up summary providers for the preferences.
     *
     * @param p The preference to set up summary provider.
     */
    private void setPreferenceSummary(Preference p) {
        // No need to set up preference summaries for checkbox preferences because
        // they can be set up in xml using summaryOff and summary On
        if (p instanceof ListPreference) {
            p.setSummaryProvider(ListPreference.SimpleSummaryProvider.getInstance());
        } else if (p instanceof EditTextPreference) {
            p.setSummaryProvider(EditTextPreference.SimpleSummaryProvider.getInstance());
        }
    }
}