android - material checkbox style after customize

Question

My customized checkbox (MyCheckbox) has extended from androidx.appcompat.widget.AppCompatCheckBox, but the default styles don't apply to it.

<style name="AppTheme" parent="Theme.MaterialComponents.Light.NoActionBar">
    ...
    <item name="android:checkboxStyle">@style/CheckboxTheme</item>
    <item name="checkboxStyle">@style/CheckboxTheme</item>
</style>

<style name="CheckboxTheme" parent="@style/Widget.AppCompat.CompoundButton.CheckBox">
     <!-- for example try to change background -->
    <item name="android:background">@color/colorPrimary</item>
</style>

but did not change anything in preview and runtime.

Also, I migrated on MaterialComponent (extending from com.google.android.material.checkbox.MaterialCheckBox) version:

com.google.android.material:material:1.1.0-beta01

and using @style/Widget.MaterialComponents.CompoundButton.CheckBox for style. but DIDN'T change.

NOTE: This issue fixes just when I mentioned the style for each instance:

            <com.something.MyCheckBox
                android:id="@+id/ch"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="some thing"
                style="@style/CheckboxTheme"
             />

but I want to set this style for all instances of this class. Could you help me?

Answer 1

The MaterialCheckBox provided by the Material Components library uses the checkboxStyle attribute defined in the theme.
Just override this attribute to define globally the style in your app:

<style name="AppTheme" parent="Theme.MaterialComponents.DayNight">
   <!-- .... -->
   <item name="checkboxStyle">@style/MyCheckBox</item>
</style>

If you want to customize the color you can use the materialThemeOverlay attribute in the style:

<style name="MyCheckBox" parent="@style/Widget.MaterialComponents.CompoundButton.CheckBox">
   <item name="materialThemeOverlay">@style/ThemeOverlay.CheckBox</item>
</style>

with:

  <style name="ThemeOverlay.CheckBox" parent="">
    <item name="colorSecondary">@color/....</item>   <!-- checked -->
    <item name="colorOnSurface">@color/.....</item>  <!-- unchecked -->
  </style>

You can also apply the style to the single checkbox using:

<com.google.android.material.checkbox.MaterialCheckBox
    style="@style/MyCheckBox"
    ..>

As alternative you can also use the android:theme in the layout, but it doesn't work globally.

<com.google.android.material.checkbox.MaterialCheckBox
    ...
    android:theme="@style/ThemeOverlay.CheckBox"/>

Just a note.
The colorTint selector is defined programmatically in the MaterialCheckBox code. You can also define a custom colorTint selector adding the buttonTint attribute in your custom style. In this case the colors defined above are ignored.