在摘要中显示EditTextPreference的值

Question

我正在学习如何在Android中开发并想要进行设置活动,

我的设置活动

public class Main extends Activity  {


    protected SettingsFragment settingsFragment;


    @SuppressLint("NewApi")
    @TargetApi(11)
    public class SettingsFragment extends PreferenceFragment implements
            SharedPreferences.OnSharedPreferenceChangeListener {


        @Override
        public void onCreate(Bundle savedInstanceState) {

            super.onCreate(savedInstanceState);
            addPreferencesFromResource(R.xml.preferences);
            setSummaries();


        }


        @Override
        public void onResume() {
            final SharedPreferences sh = getPreferenceManager().getSharedPreferences() ;
            super.onResume();
            sh.registerOnSharedPreferenceChangeListener(this);

        }

        @Override
        public void onPause() {
            final SharedPreferences sh = getPreferenceManager().getSharedPreferences() ;
            super.onPause();
            sh.unregisterOnSharedPreferenceChangeListener(this);
        }

        @SuppressLint("NewApi")
        public void setSummaries(){

           final SharedPreferences sh = getPreferenceManager().getSharedPreferences() ;


            //Pref1
            Preference stylePref = findPreference("editTextPref");
            stylePref.setSummary(sh.getString("editTextPref", ""));

            //here the other preferences..
        }


        @Override
        public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
            if (key.equals("editTextPref")) {
                Preference pref = settingsFragment.findPreference(key);
                // Set summary to be the user-description for the selected value
                pref.setSummary(sharedPreferences.getString(key, ""));

            }
            //here the others preferences
        }
    }//End fragment

    @SuppressLint("NewApi")
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        settingsFragment = new SettingsFragment();
        getFragmentManager().beginTransaction()
                .replace(android.R.id.content, settingsFragment)
                .commit();


    }


}

和我的res/preferences.xml档案

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
    <PreferenceCategory
        android:title="BTA"
        xmlns:android="http://schemas.android.com/apk/res/android">


        <EditTextPreference
            android:key="editTextPref"
            android:title="Numero de telephone"
            android:summary="This allows you to enter a string"
            android:defaultValue="*"/>

    </PreferenceCategory>

</PreferenceScreen>

所以现在我有设置活动的活动.但我想显示EditTextPref的值android:summary.我找到了很多主题,但所有功能都已弃用.

编辑:感谢@Ace_McIntosh,我为想要它的人编辑了我的代码,它现在正在运行.

Answer 1

如果您使用的是AndroidX 首选项库，则可以使用属性app:useSimpleSummaryProvider。例如：

<EditTextPreference
        app:key="edittext"
        app:title="@string/title_edittext_preference"
        app:useSimpleSummaryProvider="true"
        app:dialogTitle="@string/dialog_title_edittext_preference"/>

您可以在此处阅读完整的示例。

Answer 2

只是覆盖getSummary的EditTextPreference,那么你会得到与显示总结其价值EditTextPreference.

public class EditSummaryPreference extends EditTextPreference {
    ...// omit constructor

    @Override
    public CharSequence getSummary() {
        return getText();
    }
}

Answer 3

只需在所需的 Preference 对象上使用setSummary 方法。在为您希望更新的每个条目（即，EditTextPreference您案例中的所有条目）恢复设置片段时调用它，并OnSharedPreferenceChangeListener在具体SharedPreferences对象上注册一个（以便您可以在更改摘要时更新） - 并传递它所需的 EditTextPreference 值（您可以通过其getText()方法获得）。

MyPreferenceFragment像这样实现它（我不保证它会立即起作用，它的目的只是给你一个想法）：

public class MyPreferenceFragment extends PreferenceFragment implements SharedPreferences.OnSharedPreferenceChangeListener {
    SharedPreferences sharedPreferences;

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

        // load the preferences from your XML resource (which I assume you already do anyway)
        addPreferencesFromResource(R.xml.preferences);
    }

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

        sharedPreferences = getPreferenceManager().getSharedPreferences();

        // we want to watch the preference values' changes
        sharedPreferences.registerOnSharedPreferenceChangeListener(this);

        Map<String, ?> preferencesMap = sharedPreferences.getAll();
        // iterate through the preference entries and update their summary if they are an instance of EditTextPreference
        for (Map.Entry<String, ?> preferenceEntry : preferencesMap.entrySet()) {
            if (preferenceEntry instanceof EditTextPreference) {
                updateSummary((EditTextPreference) preferenceEntry);
            }
        }
    }

    @Override
    public void onPause() {
        sharedPreferences.unregisterOnSharedPreferenceChangeListener(this);
        super.onPause();
    }

    @Override
    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,
                                          String key) {
        Map<String, ?> preferencesMap = sharedPreferences.getAll();

        // get the preference that has been changed
        Object changedPreference = preferencesMap.get(key);
        // and if it's an instance of EditTextPreference class, update its summary
        if (preferencesMap.get(key) instanceof EditTextPreference) {
            updateSummary((EditTextPreference) changedPreference);
        }
    }

    private void updateSummary(EditTextPreference preference) {
        // set the EditTextPreference's summary value to its current text
        preference.setSummary(preference.getText());
    }
}

Answer 4

（在Kotlin中）我希望做一些更简单的事情，只是创建一个扩展EditTextPreference的类：

import android.content.Context
import android.support.v7.preference.EditTextPreference
import android.util.AttributeSet

/**
 * This class was created by Anthony M Cannon on 17/04/2018.
 */
class SummarisedEditTextPreference @JvmOverloads constructor(context: Context,
    attrs: AttributeSet? = null) : EditTextPreference(context, attrs) {

    private var mOnChangeListener: OnPreferenceChangeListener? = null

    init {
        super.setOnPreferenceChangeListener { preference, newValue ->
            summary = newValue as String
            mOnChangeListener?.onPreferenceChange(preference, newValue) ?: true
        }
    }

    /**
    * Called when this Preference has been attached to a Preference hierarchy.
    * Make sure to call the super implementation.
    *
    * @param preferenceManager The PreferenceManager of the hierarchy.
    */
    override fun onAttachedToHierarchy(preferenceManager: PreferenceManager) {
        super.onAttachedToHierarchy(preferenceManager)
        summary = sharedPreferences.getString(key, null)
    }


    /**
     * Sets the callback to be invoked when this Preference is changed by the
     * user (but before the internal state has been updated).
     *
     * @param onPreferenceChangeListener The callback to be invoked.
     */
    override fun setOnPreferenceChangeListener(
        onPreferenceChangeListener: OnPreferenceChangeListener) {
        mOnChangeListener = onPreferenceChangeListener
    }
}

然后可以这样使用：

<<您的包裹名称>.SummarisedEditTextPreference/>

Answer 5

在androidx 库中， EditTextPreference 有app:useSimpleSummaryProvider属性。使用该属性，您无需扩展任何类或监听 SharedPreferences 上的任何更改。您可以在https://github.com/googlesamples/android-preferences/blob/master/app/src/main/res/xml/dialogs.xml查看示例代码