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.
Related
What I want to do is tell my main activity if there is a SharedPreferences file, change a bunch of strings using the values in the file. And if there is no SharedPreferences file created yet, use the default strings that are assigned in the layout (essentially do nothing).
You can save preferences with this snippet:
SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(context);
Editor edit = sp.edit();
edit.putString(yourkey, yourvalue);
edit.commit();
And you can fetch them using this:
SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(context);
sp.getString(yourkey,defaultvalue);
Why not just use the SharedPreferences#getString(String key, String defaultValue) API that let's you specify a default value?
You can try this:
PreferenceManager.getDefaultSharedPreferences(this).getString(key, defValue).
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 some Shared Preferences in my application defined in an XML file. They are EditTextPreferences. I want to display the existing values on the Preference screen so that the user doesn't have to enter the Preference Edit Dialog to see the current value of the Preference. The defaultValue is only visible in the Dialog screen. I want to see the defaultValue in the main preferences screen - maybe in the place of android:summary. How can I do this?
<EditTextPreference
android:key="PREF_LT_500"
android:title="Step 1"
android:summary="I dont want a summary - I want to show current value"
android:inputType="numberDecimal"
android:defaultValue="0.8952"
android:dialogTitle="Enter Blah " />
Thanks in advance
You could try:
yourPrefrence.getText();
Or a more generic solution:
SharedPreferences p = PreferenceManager.getDefaultSharedPreferences(this);
String ans = p.getString(keyStr, defaultValue);
When this is a Context, keyStr is the key & defaultValue is a default value in case the key is not found (usually "")
I know it's been asked before, but it doesn't seem to work for me.
I have an XML file preferences.xml in the folder res\xml. It contains an optionscreen like so:
<PreferenceScreen>
<EditTextPreference
android:name="prfEmail"
android:summary="Your account's e-mail address"
android:title="E-mail"
android:key="prfEmail" />
</PreferenceScreen>
I can make an activity from it and it shows fine. Now I'd like to read values from these preferences, but I can't seem to find it. In another activity I do:
SharedPreferences appSharedPrefs;
appSharedPrefs = getSharedPreferences("preferences",Activity.MODE_PRIVATE);
String restoredText = appSharedPrefs.getString("prfEmail",null);
Whan I'd like to print this value it gives null back. What am I doing wrong?
The app preferences are stored in the default SharedPreferences. You can access them with :
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
How to make Preferences items with programmatically filled values (like: Version, Model number...)?
Why not use android.preference.Preference directly?
<Preference
android:key="version"
android:title="#string/version" />
No edit dialog, no more attribute, and information only!!
//Set the version string in your code
findPreference("version").setSummary(version);
I accomplished this with the following:
In my application_preferences.xml I have the following preference. This makes it so it is still black (not gray), but still cannot be edited by the user. Making it gray makes it difficult to read.
<EditTextPreference
android:key="version"
android:title="#string/version"
android:enabled="false"
android:selectable="false"
android:persistent="false"
android:shouldDisableView="false"/>
In the preference activity onCreate method, get the version preference and set the title to the application version.
EditTextPreference versionPref = (EditTextPreference)findPreference("version");
String version = getPackageManager().getPackageInfo(getPackageName(), 0).versionName;
versionPref.setTitle(getString(R.string.version) + ": " + version);
You can set the preferences within you code, and check if it already is filled before you fill it. As long as you do not give users access to change this information, all they can do is "clear local data", which will cause the program to re-fill the data if you do it right.
I use this technique to store unique IDs for the device, who is logged in, etc. The user doesn't even (and should never) know what I keep track of, all they know is they have a smooth program that does what they need it to do.
Example:
SharedPreferences settings = context.getSharedPreferences("preferanceName", 0);
SharedPreferences.Editor editor = settings.edit();
int value = foo;
editor.putInt("ValueToStore", value);
editor.commit();
Kevin Westwood it is perfect thanks!!
In my case I just change the setTitle to setSummary, so the value is visible bellow the title.
String serverUrl = "http://...";
EditTextPreference pref = (EditTextPreference)findPreference("serverPrefKey");
pref.setSummary(serverUrl);