usage of findviewbyid in preferenceactivity

Question

I have a preference screen and i am specifying a layout resource using the android:layout attribute. In the preference activity i am using/inflating the preference using addPreferencesFromResource from onCreate method. Inside the layout i have few textviews and buttons.

The problem is i am unable to find any of the textviews, checkboxes and buttons using findViewById method ! Every result for findViewById returns null.

EDIT :

I need to attach a listener to the checkbox.

Can anyone please help me over here ?

EDIT 2 :

1) preference_layout.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="33dp"
    android:gravity="center_vertical"
    android:minHeight="33dp"
    android:id="@+id/preference_header_switch_item_responder_layout"
    style="?android:attr/listSeparatorTextViewStyle" >

    <CheckBox
    android:id="@+id/switchWidget"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:clickable="true"
    android:focusable="false"
    android:padding="8dip"
    android:layout_marginRight="14dip" />
</LinearLayout>

2) preference screen

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

    <Preference
        android:defaultValue="false"
        android:key="auto_responder_key"
        android:widgetLayout="@layout/preference_layout"
        android:title="@string/auto_responder">
    </Preference>

</PreferenceScreen>

3)Preference Activity onCreate:

EDIT 3:

@Override
    protected void onCreate(Bundle savedInstanceState)
    {
        if(savedInstanceState != null && savedInstanceState.containsKey(HEADERS_KEY))
        {
            headers = savedInstanceState.getParcelableArrayList(HEADERS_KEY);
        }

        super.onCreate(savedInstanceState);
        applicationContext = getApplicationContext();

        setupSimplePreferencesScreen();
//      setContentView(getListView());
        headerCompound = findViewById(R.id.switchWidget);
        headerCompoundEmail = findViewById(R.id.switchWidgetEmail);
    }

and

private void setupSimplePreferencesScreen()
    {
        if (!isSimplePreferences(this))
        {
            return;
        }

        addPreferencesFromResource(R.xml.responder_generic);

    PreferenceCategory fakeHeader = new PreferenceCategory(this);

        fakeHeader.setLayoutResource(R.layout.place_holder_auto_reply_header);

        getPreferenceScreen().addPreference(fakeHeader);
        addPreferencesFromResource(R.xml.auto_reply_sms_call_check_box_preference);
        addPreferencesFromResource(R.xml.auto_reply_preferences);

        Preference smsTemplatePreference = findPreference(SMS_TEMPLATE_KEY);
        if(smsTemplatePreference != null)
        {
            bindPreferenceSummaryToValue(smsTemplatePreference);
        }

        Preference customTemplatePreference = findPreference(SMS_CUSTOM_TEMPLATE_KEY);
        if(customTemplatePreference != null)
        {
            customTemplatePreference.setEnabled(false);
            bindPreferenceSummaryToValue(customTemplatePreference);
            getPreferenceScreen().removePreference(customTemplatePreference);
        }

        // Add 'email' preferences, and a corresponding header.

        // Add 'email header' preferences.
        addPreferencesFromResource(R.xml.email_enable_check);
        addPreferencesFromResource(R.xml.email_preferences);

        Preference passwordPreference = findPreference(EMAIL_PWD_KEY);

        if(passwordPreference != null)
        {
            bindPreferenceSummaryToValue(passwordPreference);
            // the advanced version of SMS template
        }

        Preference customPasswordPreference = findPreference(EMAIL_CUSTOM_PWD_KEY);
        if(customPasswordPreference != null)
        {
            bindPreferenceSummaryToValue(customPasswordPreference);
            getPreferenceScreen().removePreference(customPasswordPreference);
        }

        // Add 'network' preferences, and a corresponding header.
        fakeHeader = new PreferenceCategory(this);
        fakeHeader.setLayoutResource(R.layout.place_holder_network_header);

        getPreferenceScreen().addPreference(fakeHeader);
        addPreferencesFromResource(R.xml.network_preferences_check_box);

        // Add 'misc' preferences, and a corresponding header.
        fakeHeader = new PreferenceCategory(this);
        fakeHeader.setLayoutResource(R.layout.place_holder_misc_header);

        getPreferenceScreen().addPreference(fakeHeader);
        addPreferencesFromResource(R.xml.misc_preferences);
        addPreferencesFromResource(R.xml.misc_reject_ignore_check_box_preferences);

        // Bind the summaries of EditText/Switch/CheckBox preferences to
        // their values. When their values change, their summaries are updated
        // to reflect the new value, per the Android Design guidelines.
        bindPreferenceSummaryToValue(findPreference(AUTO_REPLY_SMS_KEY));
        bindPreferenceSummaryToValue(findPreference(AUTO_REPLY_CALL_KEY));
        bindPreferenceSummaryToValue(findPreference(DATA_NETWORK_KEY));
        bindPreferenceSummaryToValue(findPreference(WIFI_KEY));
        bindPreferenceSummaryToValue(findPreference(PASSCODE_KEY));
        bindPreferenceSummaryToValue(findPreference(EMAIL_USR_KEY));
        bindPreferenceSummaryToValue(findPreference(EMAIL_INT_KEY));
        bindPreferenceSummaryToValue(findPreference(AUTO_RESPONDER_KEY));
}

I tried the above code in onPostCreate as well but still the value returned is null.

I want to find checkboxes for responder_generic.xml and email_preferences.xml. Is there a way to find and add listeners to them ?

Thanks, Adithya

Answer 1

What i did was create a custom preference and it worked. I simply extended Preference class and inflated the layout provided in the layout/%MY_LAYOUT%.xml. The listeners were being called as well which is what i wanted to achieve.

This solution was nowhere i believe, hence, i adding this to community Wiki.

Note : if there is a single preference being added then single preference solution should suffice. I am adding multiple preferences on screen (in my case 2), i implemented custom preferences.

Answer 2

From what you have asked it appears that you are not able to get any view when you are using

findViewById()

so one possible reason for this behavior could be that you may not have called

 setContentView(R.id.yourlayout);

check this out in your code...

Answer 3

I had the same problem trying to put directly a RadioGroup in the PreferenceScreen. I was trying to set the checked RadioButton when creating the Activity (eg restoring the value of a boolean from sharedpreferences) but i wasn't able to findViewById or similiar from the OnCreate method. Here's my (ugly but working) solution: I extended the RadioButton class:

public class RadioButtonSettings extends RadioButton {
public RadioButtonSettings(Context context, AttributeSet attrs) {
    super(context, attrs);
    boolean isLocal = context.getSharedPreferences("",Context.MODE_PRIVATE).getBoolean("local",true);
    switch(getId()){
        case R.id.radio_in:
            if(isLocal)
                setChecked(true);
            break;
        case R.id.radio_out:
            if(!isLocal)
                setChecked(true);
            break;
        default:
            break;
    }
}}

then put somewhere in your preferences.xml file (loaded by the PreferenceActivity):

<PreferenceCategory
android:title="CATEGORY EXAMPLE">
<Preference android:layout="@xml/category_one"
    android:selectable="false"
    android:key="radiobuttons">
</Preference>
</PreferenceCategory>

and finally create another file in the res/xml directory (named category_one.xml) and put:

<RadioGroup
    android:id="@+id/radio"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <your.package.RadioButtonSettings
        tools:context="your.package.SettingsActivity"
        android:id="@+id/radio_in"
        android:text="@string/radioIn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">
    </your.package.RadioButtonSettings>
    <your.package.RadioButtonSettings
        tools:context="your.package.SettingsActivity"
        android:id="@+id/radio_out"
        android:text="@string/radioOut"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">
    </your.package.RadioButtonSettings>
</RadioGroup>

You could also use the android:onClick="" option from the xml file to get the OnClickListener. In the specific case it was a simple check for a boolean "local" (radiobutton "in" and radiobutton "out"). You can also obviously override other classic methods. I think maybe it's a better solution than extending the entire Preference class. Hoping it will help someone.