So I am trying to implement a preferences menu in my app. I used the standard generated template in android studio. THe issue is that now I can't figure out how save the values the user specifies. I thought about using a click listener to determine when a user clicked a checkbox and then getting the actual value of the checkbox and saving that to sharedpreferences, but I can't figure out how to do it.
Does anyone have any suggestions on how use onClick in a preference activity?
OK, we seem to be on the right track about the system storing the values automatically, but whenever I try to reference them from my main class, it always returns null. Here is my code:
boolean trueorfalse = PreferenceManager.getDefaultSharedPreferences(getActivity())
.getBoolean("my_key", false)
;
So I assume you've already defined your Preferences in res --> xml and it looks something like this:
<PreferenceScreen
xmlns:android="http://schemas.android.com/apk/res/android">
<CheckBoxPreference
android:key="my_key"
android:summary="#string/desc_string"
android:title="#string/title_string" />
</PreferenceScreen>
As soon as the user checks or unchecks the CheckBox the systen will automatically create an entry in the default Preference-file which you can access like this:
PreferenceManager.getDefaultSharedPreferences(this)
.getBoolean("my_key", false);
But back to your initial question: If you want to assign an onClick-Listener to your preference you have to do something like this:
Preference myPreference = (Preference) findPreference("my_key");
myPreference .setOnPreferenceClickListener(new OnPreferenceClickListener() {
#Override
public boolean onPreferenceClick(Preference preference) {
// do something
}
});
Note: In this example it isn't a CheckBoxPreference, it's just a simple Preference
I tried the same in my SettingsMenu by implementing OnSharedPreferenceChangeListener
public class SettingsMenu extends PreferenceActivity implements OnSharedPreferenceChangeListener {
#Override
public void onCreate(Bundle savedInstanceState) {
Context context = getApplicationContext();
SharedPreferences menu_settings = PreferenceManager.getDefaultSharedPreferences(context);
menu_settings.registerOnSharedPreferenceChangeListener(this);
...
}
#Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
// check the checkboxes
}
}
Hope it helps :)
Related
I'm a bit unclear on how Preference.setSummary() is supposed to work. Is this method supposed to update a menu item's summary in a Preference fragment in a non-volatile way? In other words, is the displayed summary supposed to persist after closing and re-opening the preference menu fragment?
I thought it is supposed to work like this, yet any time I press the back button and then re-open the preference menu the summaries are blank again.
public class FragmentSettingsMenu extends com.takisoft.fix.support.v7.preference.PreferenceFragmentCompat {
private SharedPreferences.OnSharedPreferenceChangeListener listener;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Load the preferences from the XML resource
addPreferencesFromResource(R.xml.preferences);
listener = new SharedPreferences.OnSharedPreferenceChangeListener() {
public void onSharedPreferenceChanged(SharedPreferences prefs, String key) {
if (key.equals("pref_wood")) {
Preference woodPref = findPreference(key);
String color = woodPref.getSharedPreferences().getString(key, "Maple");
MainActivity.getGLSurfaceView().setTexture(color);
woodPref.setSummary(color); // Set summary to be the user-description for the selected value
}
}
};
}
}
Is this method supposed to update a menu item's summary in a Preference fragment in a non-volatile way?
No.
In other words, is the displayed summary supposed to persist after closing and re-opening the preference menu fragment?
No.
I'm getting a compiler error cannot resolve method findPreference when I try to intialize an OnSharedPreferencesChanged listener in my MainActivity. According to the answer here:
findPreference() should be called from a class implementing PreferenceActivity interface
but I don't understand what the code to do this would be. How can I get rid of the compiler error and successfully set listeners for preference changes?
MainActivity.java
public class MainActivity extends FragmentActivity implements SharedPreferences.OnSharedPreferenceChangeListener {
private SharedPreferences.OnSharedPreferenceChangeListener listener;
#Override
protected void onCreate(Bundle savedInstanceState) {
...
//Test preference menu
listener = new SharedPreferences.OnSharedPreferenceChangeListener() {
public void onSharedPreferenceChanged(SharedPreferences prefs, String key) {
if (key.equals("pref_wood")) {
Preference woodPref = findPreference(key); //COMPILER ERROR HERE
MainActivity.getGLSurfaceView().setTexture("");
// Set summary to be the user-description for the selected value
woodPref.setSummary(sharedPreferences.getString(key, ""));
}
}
}
}
}
findPreference is a method which is part of both PreferenceFragment and PreferenceActivity - these are the Fragments/Activities that actually show your Preference screen (the activity is deprecated and you should be using the PreferenceFragment).
You're trying to use it in your MainActivity. This doesn't work because the Preference objects don't actually exist on this screen (they exist in another activity that usually have a PreferenceFragment as part of it). If you need to get access to a preference value of a preference in an activity that is not your preference screen, use SharedPreferences, something like:
SharedPreferences sharedPref = getActivity().getPreferences(Context.MODE_PRIVATE);
int defaultValue = getResources().getBoolean(R.bool.saved_high_score_default);
boolean wood = sharedPref.getBoolean(pref_wood, defaultValue);
You can check out the documentation for further examples.
If your MainActivity is supposed to be a screen that shows settings, then you should probably rename it and include a preference fragment inside of it.
I believe you're also going to run into trouble with setSummary because the Preference is not part of this activity, it's part of the activity where you actually modify the preferences. setSummary is used to update the actual UI of the Preference so that if you, for example, select one of three values when using a list preference, it shows the value you just selected on the screen.
I have a Preference Screen in my android app which contains a call to the system settings via an inner Preference and some Switches options as below:
<PreferenceCategory
android:title="#string/preferences_activity_supervisor_settings_title">
<Preference
android:key="#+id/instrument_preference"
android:title="#string/instrument_settings"
android:summary="#string/instrument_settings">
</Preference>
<com.CustomSwitchPreference
android:key="#string/prefs_super_autosend_key"
android:title="#string/prefs_super_autosend_title"
android:summary="#string/prefs_super_autosend_summary"
android:defaultValue="false"/>
...
...
My class extends PreferenceFragment and I added the resources using addPreferencesFromResource(). It works without problems.
However, the method onPreferenceTreeClick(), when I click in the Fragment (keyID = instrument_preference) the preferences always brings me key as NULL. All other options in the preference fragment I can read the key.
The question is why and how I detect the user clicked in the first element of my preference list ?
First remove + from #+id, because every time it create a new key due to #+id, thats why you get null.
And to detect SharedPreference is changed use this simple code:
public class MyPreferences extends PreferenceActivity implements SharedPreferences.OnSharedPreferenceChangeListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.fw_preferences); //deprecated
PreferenceManager.getDefaultSharedPreferences(this).registerOnSharedPreferenceChangeListener(this);
}
#Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
// handle the preference change here
}
}
Try removing #+id before the preference key name
It should be like
<Preference
android:key="instrument_preference"
android:title="#string/instrument_settings"
android:summary="#string/instrument_settings">
</Preference>
I'm writing an android app with a preferencesActivity in which selections made in my instance of preferencesActivity affect the values of other preferences items displayed. While I'm able to change the values of the underlying SharedPreferences items pogrammatically, those changed values aren't reflected in the displayed list items until I exit my preferencesActivity and reload it. Below is a stripped down version of my settings class and xml file which illustrate the problem. If a user sets Guitar as the value for the preference with the key instrumentList, I'd like the preference with key tuningChoice to revert to Standard.
//necessary import declarations go here
public class Settings extends PreferenceActivity implements OnSharedPreferenceChangeListener{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.preferences);
SharedPreferences app_preferences = PreferenceManager.getDefaultSharedPreferences(this);
app_preferences.registerOnSharedPreferenceChangeListener(this);
}
public void onSharedPreferenceChanged (SharedPreferences sharedPreferences, String key) {
Log.d("onSharedPreferencesChanged", "sharedPreferences changed. key: " + key);
Editor preferencesMod = sharedPreferences.edit();
String instrumentChoice = sharedPreferences.getString("instrumentList", "Guitar");
if(key.equals("instrumentList")) {
Log.d("Settings", "key is instrumentList. chooseTuning before if: " + sharedPreferences.getString("chooseTuning", "no luck"));
if(instrumentChoice.equals("Guitar")) {
preferencesMod.putString("chooseTuning", "Standard");
preferencesMod.commit();
Log.d("Settings", "chooseTuning after if: " + sharedPreferences.getString("chooseTuning", "ciao"));
}
}
}
}
xml file preferences.xml
<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"
android:title="Settings">
<ListPreference android:title="Choose an Instrument" android:key="instrumentList" android:entryValues="#array/instruments" android:entries="#array/instruments"/>
<ListPreference android:title="Choose Tuning" android:key="chooseTuning" android:entryValues="#array/tuningChoices" android:entries="#array/tuningChoices" android:persistent="true"/>
</PreferenceScreen>
I can call addPreferencesFromResource again in my onSharedPreferenceChanged method and that loads a duplicate of all the preferences items, displayed below the old items, with the correct values. If I could figure out some way to cancel out the initial addPreferencesFromResource called during onCreate, I guess I would be set.
Any help would be appreciated, Thanks
I do something along these lines...hopefully it helps:
ListPreference list = (ListPreference) getPreferenceManager().findPreference("myList");
list.setValue(sharedPrefs.getString("myList", "default"));
list.setOnPreferenceChangeListener(new OnPreferenceChangeListener() {
public boolean onPreferenceChange(Preference preference, Object newValue) {
sharedPrefs.put("myList", newValue.toString());
return true;
}
});
You need to prevent addPReferencesFromResource from running twice? Is this loading your default values? If so, add an additional SharedPreference called DEFAULTS_LOADED and read its value in on create like: (WARNING PSUEDO CODE):
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
SharedPreferences app_preferences = PreferenceManager.getDefaultSharedPreferences(this);
boolean loadDefaults = app_preferences.getBoolean(DEFAULTS_LOADED, true);
if(loadDefaults)
{
addPreferencesFromResource(R.xml.preferences);
Editor editor = app_preferences.edit();
editor.putBoolean(DEFAULTS_LOADED, true);
editor.commit();
}
app_preferences.registerOnSharedPreferenceChangeListener(this);
}
This will prevent you defaults from being written to the shared preferences every time your activity starts. I assume this is at least a portion of your issue.
If anyone comes to this problem, this is the solution:
ListView list = preferenceActivity.getListView();
list.performItemClick(list, 1, list.getItemIdAtPosition(1));
Maybe I am too late for answering this. But, I hope this might help beginner like me.
PackageInfo packageInfo = null;
try {
packageInfo = preference.getContext().getPackageManager().getPackageInfo(preference.getContext().getPackageName(), 0);
} catch (PackageManager.NameNotFoundException e) {
e.printStackTrace();
}
preference.setSummary(packageInfo.versionName);
in the onCreate method of my PreferenceActivity i set some Properties like this:
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
SharedPreferences.Editor editor = preferences.edit();
editor.putBoolean("pref_mykey", true);
editor.commit();
It seems to work but the View is not updating so when i open the properties the onCreate runs and changes the values. I will then see the "old" values on the Screen until i close and reopen the prefs screen, then i do see the new properties.
I already tried this after the commit:
((BaseAdapter) getPreferenceScreen().getRootAdapter()).notifyDataSetChanged();
But without any effect. I still see the "old" Prefs until i close and reopen the PreferenceActivity .
What am i doing wrong? How can i refresh the PreferenceActivity after setting values in the onCreate method?
Thanks a lot for your help.
This was buggin me all day but finally found a solution.
((ListPreference)getPreferenceScreen().findPreference("key_of_preference_in_xml_file")).setValue(code);
Your example is with a boolean so it'll have to change based on what kind of preference it is.
IE:
((CheckBoxPreference)getPreferenceScreen().findPreference("key_of_preference_in_xml_file")).setChecked(true);
If you use a PreferenceFragment than you need to inject the PreferenceScreen in the activity.
public class SettingsActivity extends Activity implements ScanFragment.OnFragmentInteractionListener {
private PreferenceScreen prefScreen;
public void setPreferenceScreen(PreferenceScreen prefScreen){
this.prefScreen = prefScreen;
}
#Override
public void onFragmentInteraction(String scanContent) {
// commiting to editor retrieved from preference manager would not refresh view
EditTextPreference pref = (EditTextPreference)this.prefScreen.findPreference(getString(R.string.preference_url_key));
pref.setText(scanContent);
}
public static class SettingsFragment extends PreferenceFragment {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Load the preferences from an XML resource
addPreferencesFromResource(R.xml.preferences);
((SettingsActivity)this.getActivity()).setPreferenceScreen(this.getPreferenceScreen());
}
}
}