handle null bundle in parsers

android/app/src/main/java/com/reactnativenavigation/params/parsers/ColorParser.java

@@ -7,6 +7,9 @@ import android.support.annotation.ColorInt;
 public class ColorParser {
     @ColorInt
     public static int parse(String str) {
+        if (str == null) {
+            return -1;
+        }
         return Color.parseColor(str);
     }
 }

android/app/src/main/java/com/reactnativenavigation/params/parsers/ScreenStyleParamsParser.java

@@ -7,6 +7,10 @@ import com.reactnativenavigation.params.ScreenStyleParams;
 public class ScreenStyleParamsParser {
     public static ScreenStyleParams parse(Bundle params) {
         ScreenStyleParams result = new ScreenStyleParams();
+        if (params == null) {
+            return result;
+        }
+
         result.statusBarColor = ColorParser.parse(params.getString("statusBarColor"));
         result.topBarColor = ColorParser.parse(params.getString("topBarColor"));
         result.navigationBarColor = ColorParser.parse(params.getString("navigationBarColor"));

android/app/src/main/java/com/reactnativenavigation/params/parsers/TitleBarButtonParamsParser.java

@@ -11,6 +11,10 @@ import java.util.List;
 public class TitleBarButtonParamsParser {
     public static List<TitleBarButtonParams> parse(Bundle params) {
         List<TitleBarButtonParams> result = new ArrayList<>();
+        if (params == null) {
+            return result;
+        }
+
         for (String key : params.keySet()) {
             result.add(parseItem(params.getBundle(key)));
         }