java Android 从preferences.xml 获取密钥
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Android Get Keys from preferences.xml
提问by liquid
I have a PreferencesActivitythat shows a preferences.xmlwith checkboxes.
我有一个PreferencesActivity显示preferences.xml带有复选框的。
preferences.xml:
preferences.xml：
<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
<PreferenceCategory android:title="Keywords">
<CheckBoxPreference android:key="Essen"
android:title="Essen"
android:selectable="true"
android:enabled="true"
android:persistent="false">
</CheckBoxPreference>
<CheckBoxPreference android:key="Kleidung"
android:title="Kleidung"
android:selectable="true"
android:enabled="true"
android:persistent="false">
</CheckBoxPreference>
</PreferenceCategory>
</PreferenceScreen>
PreferencesActivity:
首选项活动：
public class PreferencesViewController extends PreferenceActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.preferences);
}
}
Now in a different ListActivityI want to show all Keys/Titles from the checked checkboxes.
现在，ListActivity我想显示选中复选框中的所有键/标题。
I try to access the Preferences with
我尝试访问首选项
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
or
或者
SharedPreferences prefs = getSharedPreferences("mypackage_preferences", 0);
But both dont really work.
但两者都不起作用。
When I call prefs.getAll().size()the result is 0.
当我打电话时prefs.getAll().size()，结果是 0。
I can access the Keys/Title with getPreferenceScreen().getPreference(i).…but it doesn't work from a different Activity, only from the PreferenceActivity.
我可以访问 Keys/Title ，getPreferenceScreen().getPreference(i).…但它不能从不同Activity的PreferenceActivity.
Does anybody have a solution how to get this work?
有没有人有解决方案如何获得这项工作？
回答by rekaszeru
You don't need a PreferenceActivityto accomplish this.
你不需要一个PreferenceActivity来完成这个。
To access the preferences, that are used in your PreferenceActivity, you should use
要访问在 PreferenceActivity 中使用的首选项，您应该使用
SharedPreferences prefs =
PreferenceManager.getDefaultSharedPreferences(getBaseContext());
If your list of data comes from the server, than you can use a ListActivity / ExpandableListActivity / any custom activity to visualize it, but this way you need to write the handlers that change the preferences.
如果您的数据列表来自服务器，那么您可以使用 ListActivity / ExpandableListActivity / 任何自定义活动来对其进行可视化，但通过这种方式，您需要编写更改首选项的处理程序。
The common way to do this would be:
执行此操作的常用方法是：
private void saveStringPreference(final String key, final String value)
{
SharedPreferences.Editor editor = prefs.edit();
editor.putString(key, value);
editor.commit();
}
If you need, you should create similar wrappers to deal with int, boolean, etc. values.
如果需要，您应该创建类似的包装器来处理 int、boolean 等值。
回答by Ridcully
I use
我用
SharedPreferences prefs =
PreferenceManager.getDefaultSharedPreferences(getBaseContext());
And then I can access the preferences via prefs.get...(), e.g. prefs.getString(key).
Have you tried this?
然后我可以通过prefs.get...()例如访问首选项prefs.getString(key)。你试过这个吗？
Edit:Just checked - prefs.getAll()works as expected and returns a Mapwith all preferences.
编辑：刚刚检查 -prefs.getAll()按预期工作并返回Map所有首选项。
回答by Victor Ionescu
I had this problem too. This is a classic RTFM, sadly. You should put the line below in your MainActivity's onCreate() method:
我也有这个问题。遗憾的是，这是一个经典的 RTFM。您应该将以下行放在 MainActivity 的 onCreate() 方法中：
PreferenceManager.setDefaultValues(this, R.xml.preferences, false);
This info can be found in the paragraph "Setting Default Values" of http://developer.android.com/guide/topics/ui/settings.html
此信息可以在http://developer.android.com/guide/topics/ui/settings.html 的“设置默认值”段落中找到
回答by Robby Pond
You should use
你应该使用
SharedPreferences prefs = referenceManager.getDefaultSharedPreferences(this);
The preferences may be empty if you have never set them via the PreferencesActivity. Also I think your ListActivity has to be in the same package as the PreferencesActivity.
如果您从未通过 PreferencesActivity 设置首选项，则首选项可能为空。另外我认为您的 ListActivity 必须与 PreferencesActivity 在同一个包中。
