如何在Android中的ProgressDialog中为不确定的ProgressBar设置主题

<style name="CustomProgressDialog" parent="Theme.AppCompat.Light.Dialog">
    <item name="android:windowBackground">@android:color/transparent</item>
    <item name="android:windowFrame">@null</item>
    <item name="android:windowIsFloating">true</item>
    <item name="android:windowContentOverlay">@null</item>
    <item name="android:windowAnimationStyle">@android:style/Animation.Dialog</item>
    <item name="android:windowSoftInputMode">stateUnspecified|adjustPan</item>
    <item name="android:windowMinWidthMajor">@dimen/abc_dialog_min_width_major</item>
    <item name="android:windowMinWidthMinor">@dimen/abc_dialog_min_width_minor</item>
</style>

ProgressDialog progressDialog = new ProgressDialog(context, R.style.CustomProgressDialog);
progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
progressDialog.setMessage("Loading...");
progressDialog.setCancelable(false);
progressDialog.show();