blocks|key|1054866|text|这个问题和我的类似：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1054867|initialize-preferences-from-xml-in-main-activity|offset|length|1054868|只需在onCreate方法中使用以下代码：|style|CODE|1054869|PreferenceManager.setDefaultValues(this,+R.xml.preference,+false);|code-block|syntax|javascript|1054870|它将从XML中加载您的首选项，最后一个参数(readAgain)将保证用户的首选项不会被覆盖。这意味着将readAgain参数设置为false意味着只有在过去从未调用过此方法的情况下才会设置默认值，因此您不必担心每次创建活动时都会覆盖用户的设置|1054871|查看Android+API中的PreferenceManager.setDefaultValues以进行进一步的研究。|1054872|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/2874276/initialize-preferences-from-xml-in-main-activity|1|http://developer.android.com/reference/android/preference/PreferenceManager.html#setDefaultValues%2528android.content.Context,%2520int,%2520boolean%2529^0|0|0|1C|0|0|3|8|0|0|M|9|1G|9|1U|5|0|F|Y|1|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|13|8|@]|9|@$D|14|E|15|1|16]]|A|$]]|$1|F|3|G|5|6|7|17|8|@$D|18|E|19|H|I]]|9|@]|A|$]]|$1|J|3|K|5|L|7|1A|8|@]|9|@]|A|$M|N]]|$1|O|3|P|5|6|7|1B|8|@$D|1C|E|1D|H|I]|$D|1E|E|1F|H|I]|$D|1G|E|1H|H|I]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1I|8|@]|9|@$D|1J|E|1K|1|1L]]|A|$]]|$1|S|3|-4|5|6|7|1M|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z]]|10|$5|V|W|X|A|$Y|11]]]]

this question is similar to mine:
<a href="https://stackoverflow.com/questions/2874276/initialize-preferences-from-xml-in-main-activity">initialize-preferences-from-xml-in-main-activity</a>
Just use this code in <code>onCreate</code> method:
<pre><code>PreferenceManager.setDefaultValues(this, R.xml.preference, false);
</code></pre>
It will load your preferences from XML, and last parameter (<code>readAgain</code>) will guarantee that user preferences won't be overwritten. That means setting the <code>readAgain</code> argument to <code>false</code> means this will only set the default values if this method has never been called in the past so you don't need to worry about overriding the user's settings each time your Activity is created
Take a look into <a href="http://developer.android.com/reference/android/preference/PreferenceManager.html#setDefaultValues%28android.content.Context,%20int,%20boolean%29" rel="noreferrer">PreferenceManager.setDefaultValues</a> in Android API for further investigation.

blocks|key|1269692|text|请注意，如果您正在使用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1269693|getSharedPreferences(String+sharedPreferencesName,+int+sharedPreferencesMode)|offset|length|style|CODE|1269694|要检索首选项，您必须使用|1269695|PreferenceManager.setDefaultValues(Context+context,+String+sharedPreferencesName,+int+sharedPreferencesMode,+int+resId,+boolean+readAgain)|1269696|设置默认值！|1269697|例如：|1269698|PreferenceManager.setDefaultValues(this,+PREFS_NAME,+Context.MODE_PRIVATE,+R.xml.preference,+false);|1269699|我希望这能帮助到一些人。|1269700|entityMap|0|LINK|mutability|MUTABLE|url|http://developer.android.com/reference/android/content/Context.html#getSharedPreferences%2528java.lang.String,%2520int%2529|1|http://developer.android.com/reference/android/preference/PreferenceManager.html#setDefaultValues%2528android.content.Context,%2520java.lang.String,%2520int,%2520int,%2520boolean%2529^0|0|0|25|0|25|0|0|0|0|3U|0|3U|1|0|0|0|0|2S|0|0^^$0|@$1|2|3|4|5|6|7|13|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|14|8|@$D|15|E|16|F|G]]|9|@$D|17|E|18|1|19]]|A|$]]|$1|H|3|I|5|6|7|1A|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|1B|8|@$D|1C|E|1D|F|G]]|9|@$D|1E|E|1F|1|1G]]|A|$]]|$1|L|3|M|5|6|7|1H|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|1I|8|@]|9|@]|A|$]]|$1|P|3|Q|5|6|7|1J|8|@$D|1K|E|1L|F|G]]|9|@]|A|$]]|$1|R|3|S|5|6|7|1M|8|@]|9|@]|A|$]]|$1|T|3|-4|5|6|7|1N|8|@]|9|@]|A|$]]]|U|$V|$5|W|X|Y|A|$Z|10]]|11|$5|W|X|Y|A|$Z|12]]]]

Be aware that if you are using 
<a href="http://developer.android.com/reference/android/content/Context.html#getSharedPreferences%28java.lang.String,%20int%29"><code>getSharedPreferences(String sharedPreferencesName, int sharedPreferencesMode)</code></a> 

to retrieve preferences you have to use 
<a href="http://developer.android.com/reference/android/preference/PreferenceManager.html#setDefaultValues%28android.content.Context,%20java.lang.String,%20int,%20int,%20boolean%29"><code>PreferenceManager.setDefaultValues(Context context, String sharedPreferencesName, int sharedPreferencesMode, int resId, boolean readAgain)</code></a> 
to set defaults! 

For example: 
<code>PreferenceManager.setDefaultValues(this, PREFS_NAME, Context.MODE_PRIVATE, R.xml.preference, false);</code>

I hope this can help someone.

blocks|key|1054991|text|在Pixel接受的答案中：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1054992|PreferenceManager.setDefaultValues(this,+R.xml.preference,+false);|code-block|syntax|javascript|1054993|根据声明，false意味着默认值不会被覆盖。这不是它所做的，它只是一个效率标志，用于在应用程序有多个入口点时停止解析。不幸的是，测试不是针对每个首选项文件进行的，因此如果您有多个首选项文件，则必须在除第一个文件之外的所有文件上编写true代码。|offset|length|style|CODE|1054994|如果你担心效率，你可以像这样编写代码。|1054995|final+static+private+int+SPL+=+1;
SharedPreferences+sp+=+PreferenceManager.getDefaultSharedPreferences(this);
if+(sp.getInt("spl",+0)+!=+SPL)
{
++++PreferenceManager.setDefaultValues(this,+R.xml.prefs1,+true);
++++PreferenceManager.setDefaultValues(this,+R.xml.prefs2,+true);
++++sp.edit().putInt("spl",+SPL).apply();
}|1054996|如果您添加了更多的共享首选项，只需将SPL设置为一个较高的数字。|1054997|entityMap^0|0|0|5|5|37|4|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@$I|X|J|Y|K|L]|$I|Z|J|10|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|11|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|12|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|13|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|T|$]]

in Pixel's accepted answer:

<pre><code>PreferenceManager.setDefaultValues(this, R.xml.preference, false);
</code></pre>

it is stated that the <code>false</code> means that defaults won't be overwritten. This is not what it does, it is just an efficiency flag to stop the parsing if your application has more than one entry point. Unfortunately the test is not made per preference file, so if you have more than one preference file you must code <code>true</code> on all but the first.

If you are worried about efficiency, you could code something like this.

<pre><code>final static private int SPL = 1;
SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(this);
if (sp.getInt("spl", 0) != SPL)
{
 PreferenceManager.setDefaultValues(this, R.xml.prefs1, true);
 PreferenceManager.setDefaultValues(this, R.xml.prefs2, true);
 sp.edit().putInt("spl", SPL).apply();
}
</code></pre>

If you ever add more shared preferences, just set SPL to a hight number.

blocks|key|1055021|text|此外，还要确保您以前从未使用过SharedPreferences。为了确保它们没有被更改(这意味着setDefaultValues(this，xml，false)没有任何影响)，卸载你的应用程序，然后再次上传，以确保值没有被触动。这对我很有帮助。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1055022|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Also make sure you have never used the SharedPreferences before. To make sure they are not changed (which means setDefaultValues(this,xml,false) has no effect) uninstall your App and upload it again to be sure no values are touched. This helped me.

blocks|key|1269836|text|定义类扩展了android.preference.Preference|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1269837|public+class+IntegerPreference+extends+Preference+{
++++public+IntegerPreference(Context+context,+AttributeSet+attrs,+int+defStyleAttr,+int+defStyleRes)+{
++++++++super(context,+attrs,+defStyleAttr,+defStyleRes);
++++}

++++public+IntegerPreference(Context+context,+AttributeSet+attrs,+int+defStyleAttr)+{
++++++++super(context,+attrs,+defStyleAttr);
++++}

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

++++public+IntegerPreference(Context+context)+{
++++++++super(context);
++++}

++++@Override
++++protected+void+onSetInitialValue(boolean+restorePersistedValue,+Object+defaultValue)+{
++++++++super.onSetInitialValue(restorePersistedValue,+defaultValue);
++++++++persistInt((Integer)+defaultValue);
++++}

++++@Override
++++protected+Object+onGetDefaultValue(TypedArray+a,+int+index)+{
++++++++return+a.getInt(index,+-1);
++++}
}

public+class+StringSetPreference+extends+Preference+{
++++public+StringSetPreference(Context+context,+AttributeSet+attrs,+int+defStyleAttr,+int+defStyleRes)+{
++++++++super(context,+attrs,+defStyleAttr,+defStyleRes);
++++}

++++public+StringSetPreference(Context+context,+AttributeSet+attrs,+int+defStyleAttr)+{
++++++++super(context,+attrs,+defStyleAttr);
++++}

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

++++public+StringSetPreference(Context+context)+{
++++++++super(context);
++++}

++++@Override
++++protected+void+onSetInitialValue(boolean+restorePersistedValue,+Object+defaultValue)+{
++++++++super.onSetInitialValue(restorePersistedValue,+defaultValue);
++++++++persistStringSet((Set<String>)+defaultValue);
++++}

++++@Override
++++protected+Object+onGetDefaultValue(TypedArray+a,+int+index)+{
++++++++return+Stream.of(a.getTextArray(index)).map(String::valueOf).collect(Collectors.toSet());
++++}
}|code-block|syntax|javascript|1269838|定义首选XML资源|1269839|<?xml+version="1.0"+encoding="utf-8"?>
<PreferenceScreen+xmlns:android="http://schemas.android.com/apk/res/android">
++++<com.ainirobot.preferencetest.IntegerPreference
++++++++android:defaultValue="101"
++++++++android:key="III"+/>
++++<com.ainirobot.preferencetest.FloatPreference
++++++++android:defaultValue="1.2"
++++++++android:key="FFF"+/>
++++<com.ainirobot.preferencetest.StringPreference
++++++++android:defaultValue="SSS"
++++++++android:key="SSS"+/>
++++<com.ainirobot.preferencetest.BooleanPreference
++++++++android:defaultValue="True"
++++++++android:key="BBB"+/>
++++<com.ainirobot.preferencetest.StringSetPreference
++++++++android:defaultValue="@array/sset"
++++++++android:key="SSET"+/>
</PreferenceScreen>|1269840|然后初始化默认值并访问|1269841|++++PreferenceManager.setDefaultValues(this,+R.xml.preferences,+false);

++++Map<String,+?>+allKeys+=+PreferenceManager.getDefaultSharedPreferences(this).getAll();
++++int+iii+=+PreferenceManager.getDefaultSharedPreferences(this).getInt("III",+-1);
++++float+fff+=+PreferenceManager.getDefaultSharedPreferences(this).getFloat("FFF",+0);
++++Log.d(TAG,+"allKeys="+%2B+allKeys+%2B+"+iii="+%2B+iii+%2B+"+fff="+%2B+fff);|1269842|//Logcat|1269843|10-13+06:53:06.986+12594+12594+D+MainActivity:+allKeys={III=101,+BBB=true,+SSS=SSS,+FFF=1.2,+SSET=[XXX,+ZZZ,+YYY]}+iii=101+fff=1.2|1269844|entityMap^0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|Y|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|10|8|@]|9|@]|A|$]]|$1|Q|3|R|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

define class extends android.preference.Preference
<pre><code>public class IntegerPreference extends Preference {
 public IntegerPreference(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
 super(context, attrs, defStyleAttr, defStyleRes);
 }

 public IntegerPreference(Context context, AttributeSet attrs, int defStyleAttr) {
 super(context, attrs, defStyleAttr);
 }

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

 public IntegerPreference(Context context) {
 super(context);
 }

 @Override
 protected void onSetInitialValue(boolean restorePersistedValue, Object defaultValue) {
 super.onSetInitialValue(restorePersistedValue, defaultValue);
 persistInt((Integer) defaultValue);
 }

 @Override
 protected Object onGetDefaultValue(TypedArray a, int index) {
 return a.getInt(index, -1);
 }
}

public class StringSetPreference extends Preference {
 public StringSetPreference(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
 super(context, attrs, defStyleAttr, defStyleRes);
 }

 public StringSetPreference(Context context, AttributeSet attrs, int defStyleAttr) {
 super(context, attrs, defStyleAttr);
 }

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

 public StringSetPreference(Context context) {
 super(context);
 }

 @Override
 protected void onSetInitialValue(boolean restorePersistedValue, Object defaultValue) {
 super.onSetInitialValue(restorePersistedValue, defaultValue);
 persistStringSet((Set&lt;String&gt;) defaultValue);
 }

 @Override
 protected Object onGetDefaultValue(TypedArray a, int index) {
 return Stream.of(a.getTextArray(index)).map(String::valueOf).collect(Collectors.toSet());
 }
}
</code></pre>
define preference XML resource
<pre><code>&lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
&lt;PreferenceScreen xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;&gt;
 &lt;com.ainirobot.preferencetest.IntegerPreference
 android:defaultValue=&quot;101&quot;
 android:key=&quot;III&quot; /&gt;
 &lt;com.ainirobot.preferencetest.FloatPreference
 android:defaultValue=&quot;1.2&quot;
 android:key=&quot;FFF&quot; /&gt;
 &lt;com.ainirobot.preferencetest.StringPreference
 android:defaultValue=&quot;SSS&quot;
 android:key=&quot;SSS&quot; /&gt;
 &lt;com.ainirobot.preferencetest.BooleanPreference
 android:defaultValue=&quot;True&quot;
 android:key=&quot;BBB&quot; /&gt;
 &lt;com.ainirobot.preferencetest.StringSetPreference
 android:defaultValue=&quot;@array/sset&quot;
 android:key=&quot;SSET&quot; /&gt;
&lt;/PreferenceScreen&gt;
</code></pre>
then initialize default value and access
<pre><code> PreferenceManager.setDefaultValues(this, R.xml.preferences, false);

 Map&lt;String, ?&gt; allKeys = PreferenceManager.getDefaultSharedPreferences(this).getAll();
 int iii = PreferenceManager.getDefaultSharedPreferences(this).getInt(&quot;III&quot;, -1);
 float fff = PreferenceManager.getDefaultSharedPreferences(this).getFloat(&quot;FFF&quot;, 0);
 Log.d(TAG, &quot;allKeys=&quot; + allKeys + &quot; iii=&quot; + iii + &quot; fff=&quot; + fff);
</code></pre>
//Logcat
<pre><code>10-13 06:53:06.986 12594 12594 D MainActivity: allKeys={III=101, BBB=true, SSS=SSS, FFF=1.2, SSET=[XXX, ZZZ, YYY]} iii=101 fff=1.2
</code></pre>

I am using a PreferenceActivity to let the user set some values.
I am feeding it the xml file with the defined preferences.

I have set all the <code>android:defaultValue=""</code> for them.

When I start my application, I need the preferences, or if they are not set yet manually, I want the default values:

<pre><code>SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
boolean value = prefs.getBoolean("key"), false); 
</code></pre>

However, when <code>android:defaultValue="true"</code> I still get <code>false</code>. So, it looks like the defaultValues set in the XML are not used anywhere but when initializing the preferences-screen.

I don't want to hardcode the default values in the <code>getBoolean()</code> method. So, is there a way get the default-values with only defining these in 1 place?

Android Preferences: How to load the default values when the user hasn't used the preferences-screen?

Android

我使用PreferenceActivity让用户设置一些值。我将xml文件与定义好的首选项一起提供给它。我已经为他们设置了所有的android:defaultValue=""。当我启动我的应用程序时，我需要首选项，或者如果它们还没有手动设置，我需要缺省值：SharedPreferences prefs = Prefer...

问Android首选项:当用户没有使用首选项屏幕时，如何加载默认值？
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问Android首选项:当用户没有使用首选项屏幕时，如何加载默认值？
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