What causes "Parameter:listener must not be null" in Tencent/QMUI_Android?

Pass a concrete listener instance; create it inline if the callback is optional.

Tencent/QMUI_Android · error · NullPointerException

Parameter:listener must not be null

Error message

Parameter:listener must not be null

What it means

The same null-check pattern as the activity parameter: setVisibilityEventListener also requires a non-null KeyboardVisibilityEventListener to receive callbacks. A null listener is rejected with this NullPointerException before the global layout listener is installed.

Source

Thrown at qmui/src/main/java/com/qmuiteam/qmui/util/QMUIKeyboardHelper.java:155

        });
    }

    /**
     * Set keyboard visibility change event listener.
     *
     * @param activity Activity
     * @param listener KeyboardVisibilityEventListener
     */
    @SuppressWarnings("deprecation")
    public static void setVisibilityEventListener(final Activity activity,
                                                  final KeyboardVisibilityEventListener listener) {

        if (activity == null) {
            throw new NullPointerException("Parameter:activity must not be null");
        }

        if (listener == null) {
            throw new NullPointerException("Parameter:listener must not be null");
        }

        final View activityRoot = QMUIViewHelper.getActivityRoot(activity);

        final ViewTreeObserver.OnGlobalLayoutListener layoutListener =
                new ViewTreeObserver.OnGlobalLayoutListener() {

                    private final Rect r = new Rect();

                    private final int visibleThreshold = Math.round(
                            QMUIDisplayHelper.dp2px(activity, KEYBOARD_VISIBLE_THRESHOLD_DP));

                    private boolean wasOpened = false;

                    @Override
                    public void onGlobalLayout() {
                        activityRoot.getWindowVisibleDisplayFrame(r);

View on GitHub (pinned to 026e7d4866)

Solutions

Pass a concrete listener instance; create it inline if the callback is optional.
Null-check the listener and skip registration when it isn't ready yet.
Ensure the listener field is initialized before this call (constructor or onCreate).
If the callback truly is optional, wrap it in a no-op implementation instead of null.

Example fix

// before
QMUIKeyboardHelper.setVisibilityEventListener(activity, mListener); // mListener not yet set
// after
if (activity != null && mListener != null) {
    QMUIKeyboardHelper.setVisibilityEventListener(activity, mListener);
}

Defensive patterns

Strategy: validation

Validate before calling

if (activity != null && listener != null) {
    QMUIKeyboardHelper.setVisibilityEventListener(activity, listener);
}

Type guard

boolean isValidListener(KeyboardVisibilityEventListener l) { return l != null; }

Try / catch

try {
    QMUIKeyboardHelper.setVisibilityEventListener(activity, listener);
} catch (NullPointerException e) {
    Log.w(TAG, "listener not ready for keyboard registration", e);
}

Prevention

Initialize callback fields before any registration call (constructor/onCreate).
Pass an inline listener literal rather than a possibly-unassigned field.
Use Optional/no-op default implementations when the callback is optional.
Run lint/annotations (@NonNull/@Nullable) to catch null listener arguments at compile time.

When it happens

Trigger: Calling QMUIKeyboardHelper.setVisibilityEventListener(activity, null), or passing a field/callback reference that is still null at call time.

Common situations: Callback fields initialized asynchronously (e.g. set later by DI or a presenter) before the helper call, or refactoring that removed listener creation but kept the call.

Related errors

AI-assisted analysis of Tencent/QMUI_Android@026e7d4866 (2026-09-06). Data as JSON: /api/errors/d53fd105738fddad. Report an issue: GitHub.