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);
    }
}

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());
        }
    }
}

这是我的解决方案……就其价值而言

package com.example.PrefTest;

import android.content.SharedPreferences;
import android.content.SharedPreferences.OnSharedPreferenceChangeListener;
import android.os.Bundle;
import android.preference.EditTextPreference;
import android.preference.ListPreference;
import android.preference.Preference;
import android.preference.PreferenceActivity;
import android.preference.PreferenceGroup;
import android.preference.PreferenceManager;

public class Preferences extends PreferenceActivity implements
        OnSharedPreferenceChangeListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.preferences);
        PreferenceManager.setDefaultValues(Preferences.this, R.xml.preferences,
            false);
        initSummary(getPreferenceScreen());
    }

    @Override
    protected void onResume() {
        super.onResume();
        // Set up a listener whenever a key changes
        getPreferenceScreen().getSharedPreferences()
                .registerOnSharedPreferenceChangeListener(this);
    }

    @Override
    protected void onPause() {
        super.onPause();
        // Unregister the listener whenever a key changes
        getPreferenceScreen().getSharedPreferences()
                .unregisterOnSharedPreferenceChangeListener(this);
    }

    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,
            String key) {
        updatePrefSummary(findPreference(key));
    }

    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 {
            updatePrefSummary(p);
        }
    }

    private void updatePrefSummary(Preference p) {
        if (p instanceof ListPreference) {
            ListPreference listPref = (ListPreference) p;
            p.setSummary(listPref.getEntry());
        }
        if (p instanceof EditTextPreference) {
            EditTextPreference editTextPref = (EditTextPreference) p;
            if (p.getTitle().toString().toLowerCase().contains("password"))
            {
                p.setSummary("******");
            } else {
                p.setSummary(editTextPref.getText());
            }
        }
        if (p instanceof MultiSelectListPreference) {
            EditTextPreference editTextPref = (EditTextPreference) p;
            p.setSummary(editTextPref.getText());
        }
    }
}

如果你正在使用AndroidX，你可以使用一个自定义的SummaryProvider。此方法可用于任何首选项。

来自文档的例子(Java):

EditTextPreference countingPreference = (EditTextPreference) findPreference("counting");

countingPreference.setSummaryProvider(new SummaryProvider<EditTextPreference>() {
    @Override
    public CharSequence provideSummary(EditTextPreference preference) {
        String text = preference.getText();
        if (TextUtils.isEmpty(text)){
            return "Not set";
        }
        return "Length of saved value: " + text.length();
    }
});

来自文档的例子(Kotlin):

val countingPreference = findPreference("counting") as EditTextPreference

countingPreference.summaryProvider = SummaryProvider<EditTextPreference> { preference ->
    val text = preference.text
    if (TextUtils.isEmpty(text)) {
        "Not set"
    } else {
        "Length of saved value: " + text.length
    }
}

实际上，CheckBoxPreference确实能够根据复选框值指定不同的摘要。请参阅android:summaryOff和android:summaryOn属性(以及相应的CheckBoxPreference方法)。