feat(android): Add WebColor utility for parsing color (#3947)

android/capacitor/src/main/java/com/getcapacitor/Bridge.java

@@ -26,6 +26,7 @@
 import com.getcapacitor.cordova.MockCordovaWebViewImpl;
 import com.getcapacitor.util.HostMask;
 import com.getcapacitor.util.PermissionHelper;
+import com.getcapacitor.util.WebColor;
 import java.io.File;
 import java.net.SocketTimeoutException;
 import java.net.URL;
@@ -400,7 +401,7 @@ private void initWebView() {
         String backgroundColor = this.config.getString("android.backgroundColor", this.config.getString("backgroundColor", null));
         try {
             if (backgroundColor != null) {
-                webView.setBackgroundColor(Color.parseColor(backgroundColor));
+                webView.setBackgroundColor(WebColor.parseColor(backgroundColor));
             }
         } catch (IllegalArgumentException ex) {
             Logger.debug("WebView background color not applied");

android/capacitor/src/main/java/com/getcapacitor/util/WebColor.java

@@ -0,0 +1,28 @@
+package com.getcapacitor.util;
+
+import android.graphics.Color;
+
+public class WebColor {
+
+    /**
+     * Parse the color string, and return the corresponding color-int. If the string cannot be parsed, throws an IllegalArgumentException exception.
+     * @param colorString The hexadecimal color string. The format is an RGB or RGBA hex string.
+     * @return The corresponding color as an int.
+     */
+    public static int parseColor(String colorString) {
+        String formattedColor = colorString;
+        if (colorString.charAt(0) != '#') {
+            formattedColor = "#" + formattedColor;
+        }
+
+        if (formattedColor.length() != 7 && formattedColor.length() != 9) {
+            throw new IllegalArgumentException("The encoded color space is invalid or unknown");
+        } else if (formattedColor.length() == 7) {
+            return Color.parseColor(formattedColor);
+        } else {
+            // Convert to Android format #AARRGGBB from #RRGGBBAA
+            formattedColor = "#" + formattedColor.substring(7) + formattedColor.substring(1, 7);
+            return Color.parseColor(formattedColor);
+        }
+    }
+}