alibaba/ARouter · error · HandlerException

Parameter is invalid!

Error message

Parameter is invalid!

What it means

_ARouter.build(String path) throws HandlerException when the path argument is null or empty. A route path is mandatory to construct a Postcard, so the library validates it immediately before consulting PathReplaceService.

Source

Thrown at arouter-api/src/main/java/com/alibaba/android/arouter/launcher/_ARouter.java:184

    static void setLogger(ILogger userLogger) {
        if (null != userLogger) {
            logger = userLogger;
        }
    }

    static void inject(Object thiz) {
        AutowiredService autowiredService = ((AutowiredService) ARouter.getInstance().build("/arouter/service/autowired").navigation());
        if (null != autowiredService) {
            autowiredService.autowire(thiz);
        }
    }

    /**
     * Build postcard by path and default group
     */
    protected Postcard build(String path) {
        if (TextUtils.isEmpty(path)) {
            throw new HandlerException(Consts.TAG + "Parameter is invalid!");
        } else {
            PathReplaceService pService = ARouter.getInstance().navigation(PathReplaceService.class);
            if (null != pService) {
                path = pService.forString(path);
            }
            return build(path, extractGroup(path), true);
        }
    }

    /**
     * Build postcard by uri
     */
    protected Postcard build(Uri uri) {
        if (null == uri || TextUtils.isEmpty(uri.toString())) {
            throw new HandlerException(Consts.TAG + "Parameter invalid!");
        } else {
            PathReplaceService pService = ARouter.getInstance().navigation(PathReplaceService.class);
            if (null != pService) {

View on GitHub (pinned to 84f451d244)

Solutions

1. Validate the path is non-empty before calling build/hasRoute
2. Log the source of the path (extra/config) to find why it is empty
3. Provide a fallback route or early return when the path is blank
4. If paths come through PathReplaceService, ensure the replacement doesn't return an empty string

Example fix

// before
String path = getIntent().getStringExtra("target");
ARouter.getInstance().build(path).navigation(); // HandlerException if empty
// after
String path = getIntent().getStringExtra("target");
if (!TextUtils.isEmpty(path)) {
    ARouter.getInstance().build(path).navigation();
} else {
    finish();
}

if (path == null || path.trim().isEmpty()) {
    throw new IllegalArgumentException("route path must not be empty");
}

public static boolean isValidPath(String p) { return p != null && !p.trim().isEmpty(); }

try {
    ARouter.getInstance().build(path).navigation();
} catch (HandlerException e) {
    Log.w(TAG, "Invalid route path", e);
}

When it happens

Trigger: Calling ARouter.build("") or build(null) directly, or a hasRoute/isRouteExist call that forwards an empty path string (e.g. a path variable that resolved to empty).

Common situations: Path loaded from remote config, intent extra, or database that came back empty; string concatenation producing ""; typo passing the group instead of the full path.

Related errors

• Parameter invalid!
• The field '<fieldName>' is null, in class '<className>!
• ARouter::Init::Invoke init(context) first!
• ARouterCore::Init::Invoke init(context) first!
• Extract the default group failed, the path must be start wit

AI-assisted analysis of alibaba/ARouter@84f451d244 (2026-09-06). Data as JSON: /api/errors/df47fdb75ecd1e77. Report an issue: GitHub.