activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="add Filter"
    android:id="@+id/ButtonAddFilter"
    android:layout_alignParentTop="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Remove Filter"
    android:id="@+id/ButtonRemoveFilter"
    android:layout_alignParentTop="true"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true" />
</RelativeLayout>

MainActivity.java

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Button buttonAddFilter = (Button) findViewById(R.id.ButtonAddFilter);
    buttonAddFilter.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(MainActivity.this, FilterService.class);
            startService(intent);
        }
    });

    Button buttonRemoveFilter = (Button) findViewById(R.id.ButtonRemoveFilter);
    buttonRemoveFilter.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(MainActivity.this, FilterService.class);
            stopService(intent);
        }
    });
}
}

filter.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">

<ImageView
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

</LinearLayout>

FilterService.java

public class FilterService extends Service {

private View mView;
private WindowManager mWindowManager;

@Override
public int onStartCommand(Intent intent, int flags, int startId) {

    LayoutInflater layoutInflater = LayoutInflater.from(this);

    WindowManager.LayoutParams layoutParams = new WindowManager.LayoutParams(
            WindowManager.LayoutParams.MATCH_PARENT,
            WindowManager.LayoutParams.MATCH_PARENT,
            WindowManager.LayoutParams.TYPE_SYSTEM_OVERLAY,    
            WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH,
            PixelFormat.TRANSLUCENT                       
    );

    mWindowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE);

    mView = layoutInflater.inflate(R.layout.filter, null);

    mView.setBackgroundColor(Color.argb(80, 0, 0, 0));

    mWindowManager.addView(mView, layoutParams);

    return START_NOT_STICKY;
}

@Override
public void onDestroy() {
    super.onDestroy();
    mWindowManager.removeView(mView);
}

@Nullable
@Override
public IBinder onBind(Intent intent) {
    return null;
}
}

これは画面にフィルターをかける処理です。この場合、ステータスバーが暗くなりません。
ステータスバーの場所までmWindowManagerを反映させる、またはステータスバーを違和感が無いように暗くする処理はあるのでしょうか。