Adding List Preference Settings using Preference Fragment Compat

In this blog post we will see how we can add a Preference List in Settings which will display a list of radio buttons in UI which user can choose from. In Open Event Orga App, the Organizer had a choice to switch between viewing Net Sales or Gross Sales in the App’s Dashboard. We decided to use a preference list to allow the user to select between using Net or Gross Sales.

The benefit of using Preference List and not any other storage media (like SQLite) to store the information is that, Preference List stores the information as key-value pair in SharedPreferences which makes it easy to store and extract small amount of data with strong consistency guarantees and using less time. Let’s move on to the implementation.

Implementation

Firstly add the dependency in build.gradle.

implementation “com.takisoft.fix:preference-v7:27.1.0.0”

In the preferences layout file, we will use checkboxes.

<PreferenceScreen xmlns:android=”http://schemas.android.com/apk/res/android”>

<CheckBoxPreference
android:key=”@string/gross_sales_key”
android:title=”@string/gross_sales”
android:defaultValue=”true” />

<CheckBoxPreference
android:key=”@string/net_sales_key”
android:title=”@string/net_sales”
android:defaultValue=”false” />
</PreferenceScreen>

We will create SalesDataSettings class which extends PreferenceFragmentCompat and override onCreatePreferenceFix method. We will request PreferenceManager and set SharedPreferencesName. The manager will be used to store and retrieve key-value pairs from SharedPreferences. Using setPreferencesFromResource we will attach the layout file to the fragment.

PreferenceManager manager = getPreferenceManager();
manager.setSharedPreferencesName(Constants.FOSS_PREFS);

setPreferencesFromResource(R.xml.sales_data_display, rootKey);

We are using CheckBox Preferences and modifying their behaviour to work as a Radio Preference List because Radio reference is not provided by Android. We are initializing two checkboxes and attaching a preference listener to unset all other checkboxes which one is selected.

CheckBoxPreference netSales = (CheckBoxPreference) findPreference(NET_SALES);
CheckBoxPreference grossSales = (CheckBoxPreference) findPreference(GROSS_SALES);

Preference.OnPreferenceChangeListener listener = (preference, newValue) -> {
String key = preference.getKey();

switch (key) {
case GROSS_SALES:
netSales.setChecked(false);
break;
case NET_SALES:
grossSales.setChecked(false);
break;
default:
break;
}
return (Boolean) newValue;
};

netSales.setOnPreferenceChangeListener(listener);
grossSales.setOnPreferenceChangeListener(listener);

We can load SalesDataDisplay Fragment class when a preference button is clicked using fragment transactions as shown below.

findPreference(getString(R.string.sales_data_display_key)).setOnPreferenceClickListener(preference -> {
getFragmentManager().beginTransaction()
.replace(R.id.fragment_container, SalesDataSettings.newInstance())
.addToBackStack(null)
.commit();
return true;
});

References

  1. Shared Preferences Documentation https://developer.android.com/reference/android/content/SharedPreferences
  2. Gericop Takisoft Android-Support-Preference-V7-Fix https://github.com/Gericop/Android-Support-Preference-V7-Fix
  3. Codebase for Open Event Organizer App https://github.com/fossasia/open-event-orga-app
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Implementation of Set Different Language for Query in SUSI Android

SUSI.AI has many skills. Some of which are displaying web search of a certain query, provide a list of relevant information of a topic, displaying a map of the certain position and simple text message of any query. Previously SUSI.AI reply all query in English language but now one important feature is added in SUSI.AI and that feature is, reply query of the user in the language that user wants. But to get the reply in different language user has to send language code of that language along with query to SUSI Server. In this blog post, I will show you how it is implemented in SUSI Android app.

Different language supported in SUSI Android

Currently, different languages added in option in SUSI Android and their language code are:

Language Language Code
English en
German de
Spanish es
French fr
Italian it
Default Default language of the device.

Layout design

I added an option for choosing the different language in settings. When the user clicks on Language option a dialog box pops up. I used listpreference to show the list of different languages.

<ListPreference

  android:title=“@string/Language”

  android:key=“Lang_Select”

  android:entries=“@array/languagentries”

  android:entryValues=“@array/languagentry”>

</ListPreference>

“title” is used to show the title of setting, “entries” is used to show the list of entry to the user and “entryValue” is the value corresponding to each entry. I used listpreference because it has own UI so we don‘t have to develop our own UI for it and also it stores the string into the SharedPreferences so we don’t need to manage the values in SharedPreference. SharedPreference needed to set value in Language in settings so that once user close app and again open it setting will show same value otherwise it will show default value. We used an array of string to show the list of languages.

<string-array name=“languagentries”>

  <item>Default</item>

  <item>English</item>

  <item>German</item>

  <item>Spanish</item>

  <item>French</item>

  <item>Italian</item>

</string-array>

SetLanguage implementation

To set language user must choose Language option in setting.

On clicking Language option a dialog box pop up with the list of different languages. When the user chooses a language then we save corresponding language code in preference with key “prefLanguage” so that we can use it later to send it to the server along with the query. It also uses to send language to the server to store user language on the server, so that user can use the same language in the different client.

querylanguage.setOnPreferenceChangeListener { _, newValue ->

  PrefManager.putString(Constant.LANGUAGE, newValue.toString())

  if(!settingsPresenter.getAnonymity()) {

      settingsPresenter.sendSetting(Constant.LANGUAGE, newValue.toString(), 1)

  }

}

newValue.toString() is the value i.e language code of corresponding language.

Now when we query anything from SUSI.AI we send language code along with query to the server. Default language is default language of the device. Before sending language to the server we check language is default language or any specific language.

val language = if (PrefManager.getString(Constant.LANGUAGE, Constant.DEFAULT).equals(Constant.DEFAULT))

Locale.getDefault().language

else PrefManager.getString(Constant.LANGUAGE, Constant.DEFAULT)

And after that, we send the corresponding language along with query to the server.

clientBuilder.susiApi.getSusiResponse(timezoneOffset, longitude, latitude, source, language, query)

Reference

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