Develop Reference

Checkboxpreference change value

I have checkboxpreference in preference activity and I want that when one of the checkbox is enabled then other checkbox should get to disable and vice versa.
I wants to do that from my main class activity.
Here is my code:
Preferencecheckbox.xml
<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
<CheckBoxPreference
android:defaultValue="true"
android:icon="#drawable/img"
android:key="check1"
android:title="first" />
<CheckBoxPreference
android:defaultValue="false"
android:icon="#drawable/img2"
android:key="check2"
android:title="second" />
</PreferenceScreen>
Preferenceclass.java
public class preferenceclass extends PreferenceActivity {
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.preferencecheckbox);
}

You need to add a dependency to the checkbox you need disabled.
Like this:
<CheckBoxPreference
android:defaultValue="false"
android:icon="#drawable/img2"
android:key="check2"
android:title="second"
android:dependency="check1" />
Update
To disable other preferences via code.
final CheckBoxPreference checkbox2 = (CheakBoxPreference) findPreference("pref_checkbox2_key");
CheckBoxPreference switch = (CheakBoxPreference) findPreference("pref_switch_key");
switch.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
#Override
public boolean onPreferenceClick(Preference preference) {
if (switch.isChecked()) {
checkbox2.setEnabled(false);
} else {
checkbox2.setEnabled(true);
}
return true;
}
});
persistCheckBoxState(switch, checkbox2);
To persist the change when activity is closed, you need to get the preferences references like this and add directly below.
public void persistCheckBoxState (CheckBoxPreference switch, CheckBoxPreference checkbox2) {
if (switch.isChecked ()){
checkbox2.setEnabled(false);
} else {
checkbox2.setEnabled(true);
}
}

Maybe a ListPreference is more what you want. From a usability point of view this would make more sense. When you have to choose one selection out of many this would be the most obvious way to do it. See this post for further instructions

How to get setting value from VolumePreference

For the application I am working on, I need to have a preference screen, which has a EditTextPreference, SwitchPreference and a VolumePreference. I am using the VolumePreference as I need a preference that is set with a slider, and VolumePreference was the only one I could find that fit the bill. Here is my Preference XML:
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
<EditTextPreference
android:capitalize="words"
android:defaultValue="#string/pref_default_channel"
android:inputType="number"
android:key="pref_channel"
android:selectAllOnFocus="true"
android:singleLine="true"
android:title="#string/pref_title_channel"
android:summary="#string/pref_summary_channel"/>
<SwitchPreference
android:key="pref_customVol"
android:title="#string/pref_title_custom_vol"
android:summary="#string/pref_summary_custom_vol"
android:defaultValue="false" />
<VolumePreference
android:name="Volume Preference"
android:title="Notification Volume"
android:summary="Set your notification volume, so you will be notified when your Seahorse is almost finished running"
android:key="pref_notifVolPref"
android:dependency="pref_customVol"/>
I am able to get the value set by the SwitchPreference easily from shared preferences, using the code:
SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
boolean customVol = sharedPref.getBoolean("pref_customVol", false);
However, when I try to do the same to get the value from my VolumePreference, it always returns the default value of -1. Here is the code I use to retrieve the volume preference:
SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
int vol = sharedPref.getBoolean("pref_notifVolPref", -1);
Am I using the VolumePreference incorrectly? Do I need to create my own custom preference to display a slider preference? Has anyone had this issue before? Thanks

first extends PreferenceActivity
second add this to onCreate()
addPreferencesFromResource(R.xml.account_preferences);
Preference checkPreference = getPreferenceScreen().findPreference("checkbox_contacts_sync");
Preference.OnPreferenceChangeListener lis1 = new Preference.OnPreferenceChangeListener()
{
#Override
public boolean onPreferenceChange(Preference preference, Object o)
{
Toast.makeText(SystemManager.getAppContext(), "yess", Toast.LENGTH_LONG).show();
return true;
}
};
checkPreference.setOnPreferenceChangeListener(lis1);
and add this to layout
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:visibility="visible"
android:id="#android:id/list">
</ListView>
Or in main activity use this.
SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
SharedPreferences.OnSharedPreferenceChangeListener shListener = new SharedPreferences.OnSharedPreferenceChangeListener()
{
#Override
public void onSharedPreferenceChanged(SharedPreferences sharedPref, String key)
{
Assistance.print("change");
Toast.makeText(SystemManager.getAppContext(),"ohh",Toast.LENGTH_LONG).show();
}
};
sharedPreferences.registerOnSharedPreferenceChangeListener(shListener);

Setting Preferences Android

I´m having trouble with setting preferences in my app.
In the main layout I have the button to open the settings layout:
Button btnPreferences = (Button) findViewById(R.id.btnPreferences);
btnPreferences.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent i = new Intent("com.absolutkarlos.AppPreferenceActivity");
startActivity(i);
}
});
Then, it open the PreferenceActivity:
public class AppPreferenceActivity extends PreferenceActivity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//--load the preferences from an XML file---
addPreferencesFromResource(R.xml.user_references);
}
}
The xml file:
<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen
xmlns:android="http://schemas.android.com/apk/res/android">
<PreferenceCategory android:title="Category 1">
<CheckBoxPreference
android:title="Checkbox"
android:defaultValue="false"
android:summary="True of False"
android:key="checkboxPref" />
</PreferenceCategory>
<PreferenceCategory android:title="Category 2">
<EditTextPreference
android:summary="Enter a string"
android:defaultValue="#string/food"
android:title="Edit Text"
android:key="editTextPref"
android:name="#string/name"/>
<RingtonePreference
android:summary="Select a ringtone"
android:title="Ringtones"
android:key="ringtonePref"
android:name="Ringtone Preference" />
<PreferenceScreen
android:title="Second Preference Screen"
android:summary=
"Click here to go to the second Preference Screen"
android:key="secondPrefScreenPref" >
<EditTextPreference
android:summary="Enter a string"
android:title="Edit Text (second Screen)"
android:key="secondEditTextPref"
android:name="EditText" />
</PreferenceScreen>
</PreferenceCategory>
</PreferenceScreen>
Everything looks like its going to work ok, but when I test it, don´t save the string I want it to save.
I Mean, I click the setting button, open the setting layout, I write a text on the EditTextPreference call NAME, but it doesn´t save it, instead the LogCat: sendUserActionEvet() mView == null
So, what I´m doing wrong? Did I miss a step? or forgot to add something?
Basically, I just want to user write his name as part of the settings, this name will be shown at the main layout as a big title. The user can write a nickname if he want. It´s just a string that the app must remember always.
Thanks for your help...

As you might have read, the message:
LogCat: sendUserActionEvet() mView == null
can be ignored on S4 devices.
You need read the value of Preference, and change it, for his title, on your AppPreferenceActivity, set onResume method:
#Override
public void onResume(){
super.onResume();
EditTextPreference preference = (EditTextPreference) findPreference("secondEditTextPref");
preference.setOnPreferenceChangeListener(new Preference.OnPreferenceChangeListener() {
#Override
public boolean onPreferenceChange(Preference preference, Object newValue) {
preference.setTitle(newValue.toString());
return true;
}
});
String name = preference.getText();
if(name != null)
preference.setTitle(name);
}
Also, you must remove addPreferencesFromResource method, because is deprecated. You should use onBuildHeaders method. Here you can see an example of PreferenceActivity.

Using logical NOT with android:dependency from preferences

http://developer.android.com/reference/android/preference/Preference.html#attr_android:dependency
if I want my list to be dependent from other check preference named on_off I can do this
<ListPreference
android:defaultValue="100"
android:dependency="on_off"
android:dialogTitle="text"
android:entries="#array/display_values"
android:entryValues="#array/entry_values"
android:key="preferences_text"
android:summary="text"
android:title="text" />
and every time when the check preference on_off have value false this list preference will be disabled.
But what If I want everytime when on_off is true the list preference to be disabled ?
I need something like logical NOT for the android:dependency
is this possible ?

In preference XML, set android:disableDependentsState attribute of the "on_off" CheckBoxPreference to true. E.g.:
<CheckBoxPreference
android:disableDependentsState="true"
android:key="on_off"
android:summaryOff="Dependent is enabled"
android:summaryOn="Dependent is disabled"
android:title="Checkbox that disables its dependents state in reverse manner" />

You can implement it in the code:
chb = (CheckBoxPreference) findPreference("chb");
list = (ListPreference) findPreference("list");
chb.setOnPreferenceClickListener(new OnPreferenceClickListener() {
public boolean onPreferenceClick(Preference preference) {
list.setEnabled(!chb.isChecked());
return false;
}
});

How to remove a preference from PreferenceActivity?

I'm using PreferenceActivity. How do I remove a preference? I cannot seem to get this to work:
Preference p = findPreference("grok");
boolean worked = getPreferenceScreen().removePreference(p);
// worked == false.
So the preference is found, but the removePreference() call fails. What's the right way to do this? I'm using a preference.xml file for the keys like so:
<PreferenceScreen
xmlns:android="http://schemas.android.com/apk/res/android">
<PreferenceCategory
android:title="foo">
<CheckBoxPreference
android:key="grok" />
...
Thanks

you can remove only exact child in PreferenceGroup. So in your case, you should add some key to PreferenceCategory (with title="foo"), then findPreference with this key & then remove it child
XML:
<PreferenceScreen
xmlns:android="http://schemas.android.com/apk/res/android">
<PreferenceCategory
android:key="category_foo"
android:title="foo">
<CheckBoxPreference
android:key="grok" />
...
Code:
Preference p = findPreference("grok");
// removing Preference
((PreferenceGroup) findPreference("category_foo")).removePreference(p);

Instead of setting multiple ids, you can get the entire tree of preferences and find the parent of any preference, and then remove any of its children preferences:
public static Map<Preference,PreferenceGroup> buildPreferenceParentTree(final PreferenceActivity activity)
{
final Map<Preference,PreferenceGroup> result=new HashMap<Preference,PreferenceGroup>();
final Stack<PreferenceGroup> curParents=new Stack<PreferenceGroup>();
curParents.add(activity.getPreferenceScreen());
while(!curParents.isEmpty())
{
final PreferenceGroup parent=curParents.pop();
final int childCount=parent.getPreferenceCount();
for(int i=0;i<childCount;++i)
{
final Preference child=parent.getPreference(i);
result.put(child,parent);
if(child instanceof PreferenceGroup)
curParents.push((PreferenceGroup)child);
}
}
return result;
}
example:
final Map<Preference,PreferenceGroup> preferenceParentTree=buildPreferenceParentTree(SettingsActivity.this);
final PreferenceGroup preferenceParent=preferenceParentTree.get(preferenceToRemove);
preferenceGroup.removePreference(preferenceToRemove);
EDIT: seems there is a new API for this :
https://developer.android.com/reference/androidx/preference/Preference#setVisible(boolean)
I'm not sure if currently it's available or not, though.