How do you get the default value of an Android preference defined in XML? I don't want to repeat the definition of the default value in both the code and the preferences XML.
You can define default value in resources (/values/bool.xml):
<resources>
<bool name="mypreference_default">true</bool>
</resources>
Use the value in the preferences.xml:
<CheckBoxPreference
android:defaultValue="#bool/mypreference_default"
android:key="mypreference"
android:title="#string/mypreference_title" />
Then use in code:
SharedPreferences p = PreferenceManager.getDefaultSharedPreferences(context);
Boolean value = context.getResources().getBoolean(R.bool.mypreference_default);
Boolean b = p.getBoolean("mypreference", value);
First you need to define default values in your preference XML file.
Then you can populate preferences with default values in your main Activity by calling:
PreferenceManager.setDefaultValues(this, R.xml.preference, false);
When you need to retrieve a some preference just call:
int value = prefs.getInt("key", null);
Since your preferences are populated you won't get null value.
Create integer.xml under res/values to store integer constants.
In prefereces.xml reference "#integer/default_brightness"
In code context.getResources().getInteger(R.integer.default_brightness)
Related
How do I call the real value integer from res/values/stings.xml like below
<integer name="GUI_OK">0x9001</integer>
<integer name="GUI_Error">0x9002</integer>
R.Integer.GUI_OK is an int(2131230720) not the real value
First, don't put them in strings.xml. Put them in integers.xml.
Second, you should use context.getResources().getInteger(R.integer.GUI_OK), where context is an instance of a Context object, such as an Activity or Service.
R.integer.GUI_OK is simply a resource value which Android uses to retrieve the actual value of that resource.
I have string field <string name="categegoriesStatus">true</string>
Now inside settingsActivity I am changing its value on preference click.
final SharedPreferences sharedpreferences = getActivity().getPreferences(Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedpreferences.edit();
editor.putBoolean(getResources().getString(R.string.categegoriesStatus), false );
editor.apply();
But it is not changing it to false, but change it to some numeric value. And I don't get my desired result.
You have a string, but you want to save a boolean. Then, you should be this:
boolean result = getResources().getString(R.string.categegoriesStatus).equals("true");
editor.putBoolean(result, false );
Good luck!
You are using Sharedpreferences wrongly.
in the statement editor.putBoolean(getResources().getString(R.string.categegoriesStatus), false );
you are inserting editor.putBoolean("true", false); which is not what you are expecting it to do.
Information stored in shared preferences should be in key value format.
Read the android documentation from this link: http://developer.android.com/reference/android/content/SharedPreferences.Editor.html
Shared Preferences only saves/retrieve key value pairs. It does not change your string resource values. Once you have declared a string resource field, you cannot change it's value at runtime. Please refer to this answer.
I am new to Android and I am kind of stuck for 6 hours straight.
The problem is I don't know the name of the preferences file, and I need to get values from preferences file. I am using Android Studio and created a "Settings Activity". All the way I had not given name to any file except SettingsActivity.java.
So my question is what is the name of the Shared Preferences file (cause the application is keeping the values). Or otherwise if there is a way to find out.
Or perhaps I am missing something obvious in code. Following is my relevant code.
String key = "example_text";
final String PREF_FILE_NAME = "SettingsActivity";
SharedPreferences preferences = getSharedPreferences(PREF_FILE_NAME, MODE_PRIVATE);
String value = preferences.getString(key, " null");
EDIT 1: I have an activity named RemoteDevice.java, within this activity I have a Async Task subclass for internet usage. Now I have stored IP address through the above mentioned PreferencesActivity and now want to retrieve it. But am unable to find it.
EDIT 2: In the following code I am trying to get value from edit text.
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
<!-- NOTE: EditTextPreference accepts EditText attributes. -->
<!-- NOTE: EditTextPreference's summary should be set to its value by the activity code. -->
<EditTextPreference
android:key="example_text"
android:title="#string/pref_host_ip_address"
android:defaultValue="#string/pref_default_host_address"
android:selectAllOnFocus="true"
android:inputType="numberDecimal"
android:digits="123456789."
android:capitalize="words"
android:singleLine="true"
android:maxLines="1" />
<!-- NOTE: Hide buttons to simplify the UI. Users can touch outside the dialog to
dismiss it. -->
<!-- NOTE: ListPreference's summary should be set to its value by the activity code. -->
<ListPreference
android:key="example_list"
android:title="#string/pref_title_add_friends_to_messages"
android:defaultValue="-1"
android:entries="#array/pref_example_list_titles"
android:entryValues="#array/pref_example_list_values"
android:negativeButtonText="#null"
android:positiveButtonText="#null" />
And I am guessing here android:key is the key to be passed as arguments in
String value = preferences.getString(key, " null");
I am using Android Studio and created a "Settings Activity".
Then you get your SharedPreferences via PreferenceManager.getDefaultSharedPreferences(). Replace:
SharedPreferences preferences = getSharedPreferences(PREF_FILE_NAME, MODE_PRIVATE);
with:
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
You can use this:
String key = "example_text";
final String PREF_FILE_NAME = "SettingsActivity";
shared = getSharedPreferences(PREF_FILE_NAME, Context.MODE_PRIVATE);
String value = preferences.getString(key, " null");
But first you have to save some value with your key like:
shared.edit().putString(key,"MY_VALUE").commit();
Run your project on a real device and if a SharedPreferences file (it has .xml extension) is created you can find it in the root catalog of the device, here to be more exact:
/data/data/YOUR_PACKAGE_NAME/shared_prefs/YOUR_PREFS_NAME.xml
or
/data/data/YOUR_PACKAGE_NAME/shared_prefs/YOUR_PACKAGE_NAME_preferences.xml
By the way, you may just use getPreferences() method. Change your
SharedPreferences preferences = getSharedPreferences(PREF_FILE_NAME, MODE_PRIVATE);
into
SharedPreferences preferences = getPreferences(MODE_PRIVATE);
Your SharedPreferences file will get a default name. But keep in mind that it is worth using getPreferences() instead of getSharedPreferences() only if you won't need more than one SharedPreferences file in your project.
I'm trying to create a game. Now for some data i need to keep(music, effects, background on/of) i would like to use preferences.
I create new xml file named preferences.xml
<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >
<EditTextPreference android:key="music" android:title="Some title" android:defaultValue="true"/>
</PreferenceScreen>
Then i go to the location(with root privileges) and there is only lib folder in data/data/my.app.folder/. No shared_prefs folder.
When i try to access the preferences it is null. I tried with getSharedPreferences() and with PreferenceManager.getDefaultSharedPreferences(). What could be the reason?
Also i don't have activity for the preferences, I want to manage them manually.
How can I get over this problem?
To use shared preferences you will have to create it first. Like this:
SharedPreferences prefs = getApplicationContext().getSharedPreferences(
"music", Context.MODE_PRIVATE);
To create preferences in first time in it:
final String BACKGROUND_DEFAULT_VALUE = "on";
final String DEFAULT_TITILE = "";
final String TITILE_KEY = "title";
final String BACKGROUND_KEY = "background_key";
Editor editor= prefs.edit();
editor.putString(TITILE_KEY, DEFAULT_TITILE);
editor.putString(BACKGROUND_KEY, BACKGROUND_DEFAULT_VALUE);
editor.commit();
Than to edit/and save preferences in it:
Editor editor= prefs.edit();
editor.putString(TITILE_KEY, "new title");
editor.putString(BACKGROUND_KEY, "new background value i.e on/off");
editor.commit();
Than To read preferences:
String background_value = prefs.getString(BACKGROUND_KEY);
String title_value = prefs.getString(TITILE_KEY );
And you can see your shared preference file at location, it will be there after the creation.
/data/data/<packagename>/shared_prefs/music.xml
For more details and help, The android sdk's sample directory contains an example of retrieving and stroing shared preferences. Its located in the:
<android-sdk-home>/samples/android-<platformversion>/ApiDemos directory
Hope it helps.
There are two different types of xml files related to preferences.
The one you are showing is the xml resource file representing the preference hierarchy (screen representation).
The second one is the file containing the actual key value pairs.
Creating the first one doesn't create the second one. You'll actually need to display the file using a PreferenceActivity (or the Fragment equivalent or your own display method which - as I understand - you intend to do) or you'll have to create the preferences in code.
I have setup ability for a user to specify some settings using the in-built preference system. My preference.xml is simple, with only a ListPreference:
<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen
xmlns:android="http://schemas.android.com/apk/res/android" android:persistent="true">
<PreferenceCategory android:title="Your nuSTOCK Settings" android:persistent="true">
<ListPreference android:key="operation_section" android:entries="#array/array_nustock_section_values" android:summary="What's your operational section in nuSTOCK?" android:entryValues="#array/array_nustock_section_keys" android:title="Operation Section" android:negativeButtonText="Cancel" android:positiveButtonText="OK" android:persistent="true" android:enabled="true"/>
</PreferenceCategory>
</PreferenceScreen>
That references my Arrays, which are:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string-array name="array_nustock_section_keys">
<item>store</item>
<item>branch</item>
</string-array>
<string-array name="array_nustock_section_values">
<item>Store</item>
<item>Branch</item>
</string-array>
</resources>
And then I load it (the Preference Module) into my Activity Like this:
nustock_preferences = PreferenceManager.getDefaultSharedPreferences(getBaseContext());
After which I then prompt the user to set the values (select from only two options), by invoking the preference activity via an Intent:
Intent settingsActivity = new Intent(this,
MyPreferenceActivity.class);
startActivity(settingsActivity);
The Preference Activity is like so:
public class MyPreferenceActivity extends PreferenceActivity {
private static final String PREF_FILENAME = "nustock_preferences";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getPreferenceManager().setSharedPreferencesName(PREF_FILENAME);
addPreferencesFromResource(R.xml.preferences);
}
}
And I then try to read the preference value set by the user like this:
nustock_preferences = PreferenceManager
.getDefaultSharedPreferences(getBaseContext());
String op = nustock_preferences.getString(PREF_OPERATION_SECTION,"none");
Log.d(Tag,String.format("Operation Section : %s", op));
PROBLEM:
No matter what value of the preference I select, only value I get is the default "none" (which I've actually added as different from the actual values in the list, just to highlight the problem -- selected value never gets returned!).
So, What Am I doing wrong? I've tried many variations of this approach, but I can't get the user's selected preference! Even tried restarting the app (hoping that the preferences get set at start-up, nothing!)
But, interestingly, whenever I load the preference screen, the correct value is still selected under the ListPreference dialog!
I believe you specify a particular preference file name with getPreferenceManager().setSharedPreferencesName(PREF_FILENAME);
but later you are trying to get preference value from default preferences .getDefaultSharedPreferences(getBaseContext());
It's like writing data to table PERSON, but later trying to find it in the table DEFAULT
Either remove the setting for preference file name, or get your value from the preference file you specified