Fatal Exception: java.lang.RuntimeException: Unable to instantiate fragment mb.h: could not find Fragment constructor

[marmayy]

🐛 Describe the bug

I'm having a crash in some users (~0.1% of them) when they open an AppIntro2 activity. See the device list because I think it is very suspicious.

⚠️ Current behavior

Activity crashing sometimes

✅ Expected behavior

Activity created well

💣 Steps to reproduce

Couldn't reproduce it

📑 Your Code

build.gradle
implementation 'com.github.AppIntro:AppIntro:6.2.0'

Exception stacktrace

**Fatal Exception: java.lang.RuntimeException: Unable to start activity ComponentInfo{packagexxx.activities.IntroActivity}: androidx.fragment.app.Fragment$InstantiationException: Unable to instantiate fragment mb.h: could not find Fragment constructor**
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3298)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3437)
       at android.app.ActivityThread.handleRelaunchActivityInner(ActivityThread.java:5307)
       at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:5215)
       at android.app.servertransaction.ActivityRelaunchItem.execute(ActivityRelaunchItem.java:69)
       at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
       at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2041)
       at android.os.Handler.dispatchMessage(Handler.java:107)
       at android.os.Looper.loop(Looper.java:214)
       at android.app.ActivityThread.main(ActivityThread.java:7386)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:514)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:980)

**Caused by androidx.fragment.app.Fragment$InstantiationException: Unable to instantiate fragment mb.h: could not find Fragment constructor**
       at androidx.fragment.app.Fragment.instantiate(Fragment.java:630)
       at androidx.fragment.app.FragmentContainer.instantiate(FragmentContainer.java:57)
       at androidx.fragment.app.FragmentManager$2.instantiate(FragmentManager.java:448)
       at androidx.fragment.app.FragmentState.instantiate(FragmentState.java:81)
       at androidx.fragment.app.FragmentStateManager.<init>(FragmentStateManager.java:85)
       at androidx.fragment.app.FragmentManager.restoreSaveStateInternal(FragmentManager.java:2410)
       at androidx.fragment.app.FragmentManager.attachController(FragmentManager.java:2584)
       at androidx.fragment.app.FragmentController.attachHost(FragmentController.java:116)
       at androidx.fragment.app.FragmentActivity.lambda$init$1(FragmentActivity.java:128)
       at androidx.fragment.app.FragmentActivity.$r8$lambda$QtiQ2ZI3e38UkO1_xuJ8vE_JZj4(FragmentActivity.java)
       at androidx.fragment.app.FragmentActivity$$InternalSyntheticLambda$0$cef12c4fb802c6ea87b1fbddce076644080634cb6e3f7fb823e201a9f4f7f1ec$1.onContextAvailable(FragmentActivity.java:2)
       at androidx.activity.contextaware.ContextAwareHelper.dispatchOnContextAvailable(ContextAwareHelper.java:99)
       at androidx.activity.ComponentActivity.onCreate(ComponentActivity.java:322)
       at androidx.fragment.app.FragmentActivity.onCreate(FragmentActivity.java:249)
       **at com.github.appintro.AppIntroBase.onCreate(AppIntroBase.kt:395)
       at com.github.appintro.AppIntro2.onCreate(AppIntro2.kt:40)
       at packagexxx.activities.IntroActivity.onCreate(IntroActivity.java:21)**
       at android.app.Activity.performCreate(Activity.java:7802)
       at android.app.Activity.performCreate(Activity.java:7791)
       at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1306)
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3273)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3437)
       at android.app.ActivityThread.handleRelaunchActivityInner(ActivityThread.java:5307)
       at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:5215)
       at android.app.servertransaction.ActivityRelaunchItem.execute(ActivityRelaunchItem.java:69)
       at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
       at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2041)
       at android.os.Handler.dispatchMessage(Handler.java:107)
       at android.os.Looper.loop(Looper.java:214)
       at android.app.ActivityThread.main(ActivityThread.java:7386)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:514)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:980)

**Caused by java.lang.NoSuchMethodException: mb.h.<init> []**
       at java.lang.Class.getConstructor0(Class.java:2332)
       at java.lang.Class.getConstructor(Class.java:1728)
       at androidx.fragment.app.Fragment.instantiate(Fragment.java:615)
       at androidx.fragment.app.FragmentContainer.instantiate(FragmentContainer.java:57)
       at androidx.fragment.app.FragmentManager$2.instantiate(FragmentManager.java:448)
       at androidx.fragment.app.FragmentState.instantiate(FragmentState.java:81)
       at androidx.fragment.app.FragmentStateManager.<init>(FragmentStateManager.java:85)
       at androidx.fragment.app.FragmentManager.restoreSaveStateInternal(FragmentManager.java:2410)
       at androidx.fragment.app.FragmentManager.attachController(FragmentManager.java:2584)
       at androidx.fragment.app.FragmentController.attachHost(FragmentController.java:116)
       at androidx.fragment.app.FragmentActivity.lambda$init$1(FragmentActivity.java:128)
       at androidx.fragment.app.FragmentActivity.$r8$lambda$QtiQ2ZI3e38UkO1_xuJ8vE_JZj4(FragmentActivity.java)
       at androidx.fragment.app.FragmentActivity$$InternalSyntheticLambda$0$cef12c4fb802c6ea87b1fbddce076644080634cb6e3f7fb823e201a9f4f7f1ec$1.onContextAvailable(FragmentActivity.java:2)
       at androidx.activity.contextaware.ContextAwareHelper.dispatchOnContextAvailable(ContextAwareHelper.java:99)
       at androidx.activity.ComponentActivity.onCreate(ComponentActivity.java:322)
       at androidx.fragment.app.FragmentActivity.onCreate(FragmentActivity.java:249)
       **at com.github.appintro.AppIntroBase.onCreate(AppIntroBase.kt:395)
       at com.github.appintro.AppIntro2.onCreate(AppIntro2.kt:40)
       at packagexxx.activities.IntroActivity.onCreate(IntroActivity.java:21)**
       at android.app.Activity.performCreate(Activity.java:7802)
       at android.app.Activity.performCreate(Activity.java:7791)
       at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1306)
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3273)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3437)
       at android.app.ActivityThread.handleRelaunchActivityInner(ActivityThread.java:5307)
       at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:5215)
       at android.app.servertransaction.ActivityRelaunchItem.execute(ActivityRelaunchItem.java:69)
       at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
       at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2041)
       at android.os.Handler.dispatchMessage(Handler.java:107)
       at android.os.Looper.loop(Looper.java:214)
       at android.app.ActivityThread.main(ActivityThread.java:7386)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:514)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:980)

Java code

        Intent intent = new Intent(this, IntroActivity.class);
        startActivityForResult(intent, TUTORIALEND);

...
...

public class IntroActivity extends AppIntro2 {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Note here that we DO NOT use setContentView();

        setImmersiveMode();

        Fragment fragment1 = Intro.newInstance();
        Fragment fragment2 = Intro2.newInstance();

        addSlide(fragment1);
        addSlide(fragment2);

        setSkipButtonEnabled(true);

        setColorTransitionsEnabled(true);

        setVibrate(true);
        setVibrateDuration(70);

    }
...

📱 Tech info

• AppIntro Version: 6.2.0
• Device: Nokia 2.4, Redmi 9A, Redmi 9C, ZenFone Max Shot (ZB634KL), Redmi 7A, HOT 7, C5 2019, HOT 6 Pro, TCL A3, T6, Redmi Note 8 Pro
• Android OS Version: 8,9,10,11

[cortinico]

Not sure frankly what can be done on those type of crashes? Have you tried searching on the Google's Issue Tracker or for other libraries if they're having the same behavior?

[marmayy]

I've seen some sources that say that this could be a proguard issue:

Ex:
shadowsocks/shadowsocks-android#2332

[paolorotolo]

I'm closing this since fragment handling has changed in AppIntro 7.0.0 (Beta) which is now based on ViewPager2. Please feel free to reopen the issue if it still occurs. Thanks!