How to change Theme of "MaterialDatePicker" in Android?

Question

I've used MaterialDatePicker for the purpose of selecting a single date & also I had achieved that task but I cannot change the theme of the header & button.

        MaterialDatePicker.Builder builder;
        MaterialDatePicker materialDatePicker;

        long today = MaterialDatePicker.todayInUtcMilliseconds();
        CalendarConstraints.Builder con = new CalendarConstraints.Builder();
        con.setValidator(DateValidatorPointForward.now());
        builder.setSelection(today);
        builder.setCalendarConstraints(con.build());

        materialDatePicker = builder.build();

        findViewById(R.id.startCalender).setOnClickListener(v ->
                materialDatePicker.show(getSupportFragmentManager(), builder.toString())
        );

        materialDatePicker.addOnPositiveButtonClickListener(selection -> 
        Toast.makeText(this, materialDatePicker.getHeaderText(), 
        Toast.LENGTH_SHORT).show());

Answer 1

You have different options.
You can use:

builder.setTheme(R.style.MaterialCalendarTheme);

with:

  <style name="MaterialCalendarTheme" parent="ThemeOverlay.MaterialComponents.MaterialCalendar">
    <!-- just override the colors used in the default style -->
    <item name="colorOnPrimary">@color/primaryDarkColor</item>
    <item name="colorPrimary">@color/primaryLightColor</item>
  </style>

or you can use something like:

  <style name="MaterialCalendarTheme" parent="ThemeOverlay.MaterialComponents.MaterialCalendar">

    <!-- Header panel -->
    <item name="materialCalendarHeaderLayout">@style/MaterialCalendar.HeaderLayout1</item>
    <!-- Buttons -->
    <item name="buttonBarPositiveButtonStyle">@style/TextButton.Dialog1</item>
    <item name="buttonBarNegativeButtonStyle">@style/TextButton.Dialog1</item>
  </style>
  <style name="MaterialCalendar.HeaderLayout1" parent="Widget.MaterialComponents.MaterialCalendar.HeaderLayout">
    <!--<item name="android:background">?attr/colorPrimary</item>-->
    <item name="android:background">@color/primaryLightColor</item>
  </style>
  <style name="TextButton.Dialog1" parent="Widget.MaterialComponents.Button.TextButton.Dialog">
    <item name="android:textColor">@color/white</item>
    <item name="backgroundTint">@color/primaryDarkColor</item>
  </style>