Tencent/QMUI_Android · error · IllegalStateException

FragmentScheme#activities must be QMUIFragmentActivity.

Error message

FragmentScheme#activities must be QMUIFragmentActivity.

What it means

After the emptiness check, generateFragmentHostActivityList verifies each entry of FragmentScheme#activities is a subclass of QMUIFragmentActivity. Any entry that is not throws this IllegalStateException, since generated scheme code launches the fragment through QMUIFragmentActivity.

Solutions

1. Make every listed activity extend QMUIFragmentActivity.
2. Replace non-QMUI hosts in the activities array with your QMUIFragmentActivity subclass (e.g. MainActivity : QMUIFragmentActivity()).
3. Remove any entries that are fragments or non-host classes.

Example fix

// before
@FragmentScheme(name = "page", activities = [PlainActivity::class]) // PlainActivity : AppCompatActivity

// after
class PlainActivity : QMUIFragmentActivity() { ... }
@FragmentScheme(name = "page", activities = [PlainActivity::class])

fun validateHostActivities(activities: List<Class<*>>) =
    activities.forEach {
        check(QMUIFragmentActivity::class.java.isAssignableFrom(it)) { "$it must be QMUIFragmentActivity" }
    }

fun isQMUIFragmentActivity(cls: Class<*>): Boolean =
    QMUIFragmentActivity::class.java.isAssignableFrom(cls)

When it happens

Trigger: Passing an Activity class to activities that does not extend QMUIFragmentActivity — e.g. a plain AppCompatActivity, another custom activity base class, or a Fragment mistakenly listed.

Common situations: Migrating from plain AppCompatActivity hosts to QMUI; pointing activities at the wrong class after refactor; listing multiple hosts where only one extends QMUIFragmentActivity.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

• customFactory must implement interface…
• customFactory must implement interface…
• customMatcher must implement interface QMUISchemeMatcher.
• FragmentScheme#activities can not be empty.
• method of interface FirstFragmentFinder not found

AI-assisted analysis of Tencent/QMUI_Android@026e7d4866 (2026-09-06). Data as JSON: /api/errors/dc88215fa70216e8. Report an issue: GitHub.

Appendix: source

Thrown at arch-compiler/src/main/java/com/qmuiteam/qmui/arch/SchemeProcessor.java:399

        CodeBlock.Builder builder = CodeBlock.builder();
        TypeMirror[] activities = null;
        try {
            fragmentScheme.activities();
        } catch (MirroredTypesException mte) {
            List<? extends TypeMirror> containerMirrors = mte.getTypeMirrors();
            activities = new TypeMirror[containerMirrors.size()];
            for (int i = 0; i < activities.length; i++) {
                activities[i] = containerMirrors.get(i);
            }
        }
        if(activities == null || activities.length == 0){
            throw new IllegalStateException("FragmentScheme#activities can not be empty.");
        }
        builder.add("new $T[]{", OriginClassName);
        for(int i=0; i < activities.length; i++){
            TypeMirror item = activities[i];
            if(!isSubtypeOfType(item, QMUI_FRAGMENT_ACTIVITY_TYPE)){
                throw new IllegalStateException("FragmentScheme#activities must be QMUIFragmentActivity.");
            }
            if(i > 0){
                builder.add(",");
            }
            builder.add("$T.class", ClassName.get(item));
        }
        builder.add("}");
        return builder.build();
    }

    @Override
    public Set<String> getSupportedAnnotationTypes() {
        Set<String> types = new LinkedHashSet<>();
        types.add(ActivityScheme.class.getCanonicalName());
        types.add(FragmentScheme.class.getCanonicalName());
        return types;
    }

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