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文件
<?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。但我想在android:summary中显示EditTextPref的值。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。
只需在所需的Preference对象上使用setSummary method即可。在恢复您希望更新的每个条目的设置片段（即，您的案例中的所有EditTextPreference条目）时调用它，并在具体的OnSharedPreferenceChangeListener对象上注册SharedPreferences（以便您可以更新摘要以防更改） - 并传递所需的EditTextPreference值（您可以通过其getText()方法获得）。
像你这样在你的MyPreferenceFragment中实现它（我不保证它会对蝙蝠起作用，它只是为了给你一个想法）：
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());
}
}
只需覆盖getSummary的EditTextPreference，然后您将获得一个EditTextPreference，其值显示为摘要。
public class EditSummaryPreference extends EditTextPreference {
...// omit constructor
@Override
public CharSequence getSummary() {
return getText();
}
}
（在Kotlin中）我更喜欢做一些更简单的事情，只需创建一个扩展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
}
}
然后您可以像这样使用它：
<
.SummarisedEditTextPreference/>
上面发布的示例中有一些错误，所以我想我发布了一个有效的解决方案（也支持ListPreference和MultiSelectListPreference）
public class SettingsFragment extends PreferenceFragment implements SharedPreferences.OnSharedPreferenceChangeListener {
private SharedPreferences sharedPreferences;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.settings);
}
@Override
public void onResume() {
super.onResume();
sharedPreferences = getPreferenceManager().getSharedPreferences();
sharedPreferences.registerOnSharedPreferenceChangeListener(this);
PreferenceScreen preferenceScreen = getPreferenceScreen();
for(int i = 0; i < preferenceScreen.getPreferenceCount(); i++) {
setSummary(getPreferenceScreen().getPreference(i));
}
}
@Override
public void onPause() {
sharedPreferences.unregisterOnSharedPreferenceChangeListener(this);
super.onPause();
}
@Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
Preference pref = getPreferenceScreen().findPreference(key);
setSummary(pref);
}
private void setSummary(Preference pref) {
if (pref instanceof EditTextPreference) {
updateSummary((EditTextPreference) pref);
} else if (pref instanceof ListPreference) {
updateSummary((ListPreference) pref);
} else if (pref instanceof MultiSelectListPreference) {
updateSummary((MultiSelectListPreference) pref);
}
}
private void updateSummary(MultiSelectListPreference pref) {
pref.setSummary(Arrays.toString(pref.getValues().toArray()));
}
private void updateSummary(ListPreference pref) {
pref.setSummary(pref.getValue());
}
private void updateSummary(EditTextPreference preference) {
preference.setSummary(preference.getText());
}
}
在androidx库中，EditTextPreference具有app：useSimpleSummaryProvider属性。使用该属性，您不需要扩展任何类或监听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
@ serv-inc的回答对我有用。不知何故，其他答案只有在价值变化时才有效。
但在它运作之前，我不得不做如下改动：
@Override
public CharSequence getSummary() {
return getText();
}
它显示最初显示时，值更改时以及恢复后的值。
建立uppon Brett Cherrington回答，在Kotlin实施。有一个错误，即不支持PreferenceCategories，它在setSummary中使用额外的递归循环修复
class SettingsFragment : PreferenceFragment(), SharedPreferences.OnSharedPreferenceChangeListener {
private lateinit var sharedPreferences: SharedPreferences
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
addPreferencesFromResource(R.xml.preferences)
}
override fun onResume() {
super.onResume()
sharedPreferences = preferenceManager.sharedPreferences
sharedPreferences.registerOnSharedPreferenceChangeListener(this)
val preferenceScreen = preferenceScreen
for (i in 0 until preferenceScreen.preferenceCount) {
setSummary(getPreferenceScreen().getPreference(i))
}
}
override fun onPause() {
sharedPreferences.unregisterOnSharedPreferenceChangeListener(this)
super.onPause()
}
override fun onSharedPreferenceChanged(sharedPreferences: SharedPreferences, key: String) {
val pref = preferenceScreen.findPreference(key)
pref?.let { setSummary(it) }
}
private fun setSummary(pref: Preference) {
if (pref is EditTextPreference) {
updateSummary(pref)
} else if (pref is ListPreference) {
updateSummary(pref)
} else if (pref is MultiSelectListPreference) {
updateSummary(pref)
} else if (pref is PreferenceCategory){
// needs to loop through child preferences
for (i in 0 until pref.preferenceCount) {
setSummary(pref.getPreference(i))
}
}
}
private fun updateSummary(pref: MultiSelectListPreference) {
pref.setSummary(Arrays.toString(pref.values.toTypedArray()))
}
private fun updateSummary(pref: ListPreference) {
pref.summary = pref.value
}
private fun updateSummary(preference: EditTextPreference) {
preference.summary = preference.text
}
}
除了@Eke Koseoglu的回答。
如果您使用AndroidX首选项库，则可以从下面的Kotlin代码中设置summaryProvider。
val editTextPreference = EditTextPreference(context)
editTextPreference.summaryProvider = EditTextPreference.SimpleSummaryProvider.getInstance()
根据EditTextPreference.SimpleSummaryProvider的文件;
如果未设置任何值，则显示的摘要将为“未设置”，否则显示的摘要将是为此首选项设置的值。