First, you need to add more constructors to SomeDialog. The Context constructor is not enough since the Preference will be inflated from xml. Having the following three constructors is usually sufficient:

public SomeDialog(Context context) {
    super(context);
}

public SomeDialog(Context context, AttributeSet attrs) {
    super(context, attrs);
}

public SomeDialog(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
}

In addition to that, the SettingsFragment in your SettingsActivity needs to implement onDisplayPreferenceDialog(Preference preference) to show a custom dialog for the custom Preference.

public static class SettingsFragment extends PreferenceFragmentCompat {
    @Override
    public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
        setPreferencesFromResource(R.xml.root_preferences, rootKey);
    }

    @Override
    public void onDisplayPreferenceDialog(Preference preference) {
        if (preference instanceof SomeDialog) {
            MyDialogFragment dialogFragment = new MyDialogFragment();
            Bundle b = new Bundle();
            b.putString(MyDialogFragment.KEY, preference.getKey());
            b.putInt(MyDialogFragment.KEY_LAYOUT_RES_ID,  ((SomeDialog) preference).getDialogLayoutResource());

            dialogFragment.setArguments(b);
            dialogFragment.setTargetFragment(this, 0);
            dialogFragment.show(getFragmentManager(), null);
        } else super.onDisplayPreferenceDialog(preference);
    }
}

And, last not least, you also have to provide the custom dialog itself. This is done via a class extending DialogFragment.

My very simple DialogFragment has a TextView inside a FrameLayout, just to show it works

MyDialogFragment code:

public class MyDialogFragment extends DialogFragment {

    public static final String KEY = "key";
    public static final String KEY_LAYOUT_RES_ID = "resid";


    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
                return inflater.inflate(requireArguments().getInt(KEY_LAYOUT_RES_ID), container, false);

    }


    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        TextView textView = view.findViewById(R.id.textView);
        textView.setText(requireArguments().getString(KEY));
    }
}

• Here is a random layout called some_layout.xml:

  <?xml version="1.0" encoding="utf-8"?>
  <androidx.constraintlayout.widget.ConstraintLayout
      xmlns_android="http://schemas.android.com/apk/res/android"
      xmlns_app="http://schemas.android.com/apk/res-auto"
      xmlns_tools="http://schemas.android.com/tools"
      android_layout_width="match_parent"
      android_layout_height="match_parent"">
  
      <!-- Some views in here -->
  
  </androidx.constraintlayout.widget.ConstraintLayout>
  

• Here is a class SomeDialog.java that extends DialogPreference:

  import android.content.Context;
  
  import androidx.preference.DialogPreference;
  
  public class SomeDialog extends DialogPreference {
  
  
      public SomeDialog(Context context) {
          super(context);
      }
  
      @Override
      public int getDialogLayoutResource() {
          return R.layout.some_layout;
      }
  }
  

• And here’s the preference screen:

  <?xml version="1.0" encoding="utf-8"?>
  <PreferenceScreen xmlns_android="http://schemas.android.com/apk/res/android">
  
      <android.example.perappbrightness.SomeDialog
              android_title="@string/rate_app"
              android_summary="@string/rate_summary"
              android_key="rate_app"/>
  
  </PreferenceScreen>
  

Relevant part of crash error. The line at which MainActivty crashes is PreferenceManager.setDefaultValues(this, R.xml.preferences, false);:

java.lang.RuntimeException: Unable to start activity ComponentInfo{android.example.perappbrightness/android.example.perappbrightness.MainActivity}: android.view.InflateException: Binary XML file line #36: Error inflating class android.example.perappbrightness.SomeDialog
    Caused by: android.view.InflateException: Binary XML file line #36: Error inflating class android.example.perappbrightness.SomeDialog
android.example.perappbrightness.MainActivity.onCreate(MainActivity.java:72)

SettingsActivity.java is an untouched. It’s from the template of Android Studio.

What am I doing wrong?