Subtitle and Title alignment

lib/android/app/src/main/java/com/reactnativenavigation/parse/TitleOptions.java

         options.color = ColorParser.parse(json, "color");
         options.fontSize = FractionParser.parse(json, "fontSize");
         options.fontFamily = typefaceManager.getTypeFace(json.optString("fontFamily", ""));
+        options.alignment = Alignment.fromString(TextParser.parse(json, "alignment").get(""));
         options.component = TextParser.parse(json, "component");
         options.componentAlignment = Alignment.fromString(TextParser.parse(json, "componentAlignment").get(""));
 
     public Text text = new NullText();
     public Color color = new NullColor();
     public Fraction fontSize = new NullFraction();
+    public Alignment alignment = Alignment.Default;
     @Nullable public Typeface fontFamily;
     public Text component = new NullText();
     public Alignment componentAlignment = Alignment.Default;
         if (other.color.hasValue()) color = other.color;
         if (other.fontSize.hasValue()) fontSize = other.fontSize;
         if (other.fontFamily != null) fontFamily = other.fontFamily;
+        if (other.alignment != Alignment.Default) alignment = other.alignment;
         if (other.component.hasValue()) component = other.component;
         if (other.componentAlignment != Alignment.Default) componentAlignment = other.componentAlignment;
         validate(this);
         if (!color.hasValue()) color = defaultOptions.color;
         if (!fontSize.hasValue()) fontSize = defaultOptions.fontSize;
         if (fontFamily == null) fontFamily = defaultOptions.fontFamily;
+        if (alignment == Alignment.Default) alignment = defaultOptions.alignment;
         if (!component.hasValue()) component = defaultOptions.component;
         if (componentAlignment == Alignment.Default) componentAlignment = defaultOptions.componentAlignment;
         validate(this);

lib/android/app/src/main/java/com/reactnativenavigation/presentation/OptionsPresenter.java

         topBar.setTitleFontSize(options.title.fontSize.get(defaultTitleFontSize));
         topBar.setTitleTextColor(options.title.color.get(DEFAULT_TITLE_COLOR));
         topBar.setTitleTypeface(options.title.fontFamily);
+        topBar.setTitleAlignment(options.title.alignment);
 
         topBar.setSubtitle(options.subtitle.text.get(""));
         topBar.setSubtitleFontSize(options.subtitle.fontSize.get(defaultSubtitleFontSize));
         topBar.setSubtitleColor(options.subtitle.color.get(DEFAULT_SUBTITLE_COLOR));
         topBar.setSubtitleFontFamily(options.subtitle.fontFamily);
+        topBar.setSubtitleAlignment(options.subtitle.alignment);
 
         topBar.setBackgroundColor(options.background.color);
         topBar.setBackgroundComponent(options.background.component);

lib/android/app/src/main/java/com/reactnativenavigation/utils/UiUtils.java

 import android.os.Build;
 import android.os.Handler;
 import android.os.Looper;
+import android.support.annotation.NonNull;
 import android.util.DisplayMetrics;
 import android.view.View;
 import android.view.ViewTreeObserver;
 	}
 
 	public static float getWindowHeight(Context context) {
-		DisplayMetrics metrics = new DisplayMetrics();
-		WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
-		if (windowManager != null) {
-			windowManager.getDefaultDisplay().getMetrics(metrics);
-		}
-		return metrics.heightPixels;
+        return getDisplayMetrics(context).heightPixels;
 	}
 
+    public static float getWindowWidth(Context context) {
+        return getDisplayMetrics(context).widthPixels;
+    }
+
+    @NonNull
+    private static DisplayMetrics getDisplayMetrics(Context context) {
+        DisplayMetrics metrics = new DisplayMetrics();
+        WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
+        if (windowManager != null) {
+            windowManager.getDefaultDisplay().getMetrics(metrics);
+        }
+        return metrics;
+    }
+
     public static int getStatusBarHeight(Context context) {
         if (statusBarHeight > 0) {
             return statusBarHeight;

lib/android/app/src/main/java/com/reactnativenavigation/views/titlebar/TitleBar.java

 import com.reactnativenavigation.parse.Alignment;
 import com.reactnativenavigation.parse.params.Button;
 import com.reactnativenavigation.parse.params.Color;
+import com.reactnativenavigation.utils.UiUtils;
 import com.reactnativenavigation.utils.ViewUtils;
 import com.reactnativenavigation.viewcontrollers.ReactViewCreator;
 import com.reactnativenavigation.viewcontrollers.TitleBarReactViewController;
         if (titleTextView != null) titleTextView.setTypeface(typeface);
     }
 
+    public void setTitleAlignment(Alignment alignment) {
+        TextView title = findTitleTextView();
+        if (title == null) return;
+        alignTextView(alignment, title);
+    }
+
     public void setSubtitleTypeface(Typeface typeface) {
         TextView subtitleTextView = findSubtitleTextView();
         if (subtitleTextView != null) subtitleTextView.setTypeface(typeface);
         if (subtitleTextView != null) subtitleTextView.setTextSize(size);
     }
 
+    public void setSubtitleAlignment(Alignment alignment) {
+        TextView subtitle = findSubtitleTextView();
+        if (subtitle == null) return;
+        alignTextView(alignment, subtitle);
+    }
+
+    private void alignTextView(Alignment alignment, TextView view) {
+        view.post(() -> {
+            if (alignment == Alignment.Center) {
+                view.setX((getWidth() - view.getWidth()) / 2);
+            } else {
+                view.setX(UiUtils.dpToPx(getContext(), 16));
+            }
+        });
+    }
+
     @Nullable
     public TextView findTitleTextView() {
         List<TextView> children = ViewUtils.findChildrenByClass(this, TextView.class, textView -> textView.getText().equals(getTitle()));

lib/android/app/src/main/java/com/reactnativenavigation/views/topbar/TopBar.java

         titleBar.setSubtitleFontSize(size);
     }
 
+    public void setSubtitleAlignment(Alignment alignment) {
+        titleBar.setSubtitleAlignment(alignment);
+    }
+
     public void setTestId(String testId) {
         setTag(testId);
     }
         titleBar.setTitleTypeface(typeface);
     }
 
+    public void setTitleAlignment(Alignment alignment) {
+        titleBar.setTitleAlignment(alignment);
+    }
+
     public void setTitleComponent(String componentName, Alignment alignment) {
         titleBar.setComponent(componentName, alignment);
     }

playground/src/screens/OptionsScreen.js

           text: 'Static Title',
           color: 'black',
           fontSize: 16,
+          alignment: 'center',
           fontFamily: 'HelveticaNeue-Italic',
           largeTitle: false
         },
         subtitle: {
           text: 'Static Subtitle',
           color: 'red',
-          fontFamily: 'HelveticaNeue-Italic'
+          fontFamily: 'HelveticaNeue-Italic',
+          alignment: 'center'
         },
         background: {
           component: 'TopBarBackground'