Q:

what style has dynamically added view? 

I experience strange situation: when I put check box by code, it has diffrent style then check box added by xml file. 
this is the dynamically adding the check boxes:
LinearLayout checkboxGroup = (LinearLayout) v.findViewById(R.id.category_checkbox_group);
for(String category : categories) {
    CheckBox checkBox = new CheckBox(getActivity());
    checkBox.setText("dynamically added");
    checkBox.setOnClickListener(mCategoryChecked);
    checkboxGroup.addView(checkBox);
}

fragment of xml:
        <LinearLayout
            android:id="@+id/category_checkbox_group"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:orientation="vertical">

            <CheckBox
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="xml added" />
        </LinearLayout>

So after all I have one checkbox form xml and few checkboxes from code. 
The screen looks like below:

so my questions are: 

what style is default for dynamic views? 
how to apply this style to xml's views? 
is a easy way to change box in check box? 

A:

The style for the dynamically added view depends on the context.  In your situation the context is your activity, so the style of the added view is the style of your activity.  If you didn't setup a theme for your activity, then it is the theme of your application, that you defined in your styles.xml.  Example:
<style name="AppTheme" parent="Theme. AppCompat. Light. DarkActionBar">
</style>

You most probably inflated the xml layout from a different context.  If you are inflating it from the same context like your added views, the views should have the same style.  Try to check this. 

You can also set a style for one view in xml like that:
<View
    style="@style/Example" />

