Tive esse problema quando estava utilizando a versão 0.2.19
A solução encontrada foi reiniciando o dispositivo.
O problema apareceu sem nenhuma explicação, stopei a execução, rodei um flutter clean e nada de voltar a funcionar.
Como ele estava funcionando corretamente até o momento do erro, resolvi reiniciar o celular para ver se resolvia o problema, e sim, resolveu (aparentemente kkkk)
Dispositivo usado: Xiaomi MI MAX 2 - MIUI global 11.0.2
Timeline: Activity_launch_request time:147382 intent:Intent { cmp=com.app.teste/com.shinow.qrscan.SecondActivity }
W/ResourceType( 9495): No package identifier when getting name for resource number 0x00000000
W/art ( 9495): Before Android 4.1, method android.graphics.PorterDuffColorFilter androidx.vectordrawable.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter, android.content.res.ColorStateList, android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
I/art ( 9495): Rejecting re-init on previously-failed class java.lang.Class<androidx.core.view.ViewCompat$2>: java.lang.NoClassDefFoundError: Failed resolution of: Landroid/view/View$OnUnhandledKeyEventListener;
I/art ( 9495): at void androidx.core.view.ViewCompat.setOnApplyWindowInsetsListener(android.view.View, androidx.core.view.OnApplyWindowInsetsListener) (ViewCompat.java:2421)
I/art ( 9495): at android.view.ViewGroup androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor() (AppCompatDelegateImpl.java:779)
I/art ( 9495): at void androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor() (AppCompatDelegateImpl.java:659)
I/art ( 9495): at void androidx.appcompat.app.AppCompatDelegateImpl.setContentView(int) (AppCompatDelegateImpl.java:552)
I/art ( 9495): at void androidx.appcompat.app.AppCompatActivity.setContentView(int) (AppCompatActivity.java:161)
I/art ( 9495): at void com.shinow.qrscan.SecondActivity.onCreate(android.os.Bundle) (SecondActivity.java:39)
I/art ( 9495): at void android.app.Activity.performCreate(android.os.Bundle) (Activity.java:6854)
I/art ( 9495): at void android.app.Instrumentation.callActivityOnCreate(android.app.Activity, android.os.Bundle) (Instrumentation.java:1119)
I/art ( 9495): at android.app.Activity android.app.ActivityThread.performLaunchActivity(android.app.ActivityThread$ActivityClientRecord, android.content.Intent) (ActivityThread.java:2709)
I/art ( 9495): at void android.app.ActivityThread.handleLaunchActivity(android.app.ActivityThread$ActivityClientRecord, android.content.Intent, java.lang.String) (ActivityThread.java:2817)
I/art ( 9495): at void android.app.ActivityThread.-wrap12(android.app.ActivityThread, android.app.ActivityThread$ActivityClientRecord, android.content.Intent, java.lang.String) (ActivityThread.java:-1)
I/art ( 9495): at void android.app.ActivityThread$H.handleMessage(android.os.Message) (ActivityThread.java:1556)
I/art ( 9495): at void android.os.Handler.dispatchMessage(android.os.Message) (Handler.java:102)
I/art ( 9495): at void android.os.Looper.loop() (Looper.java:163)
I/art ( 9495): at void android.app.ActivityThread.main(java.lang.String[]) (ActivityThread.java:6388)
I/art ( 9495): at java.lang.Object java.lang.reflect.Method.invoke!(java.lang.Object, java.lang.Object[]) (Method.java:-2)
I/art ( 9495): at void com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run() (ZygoteInit.java:930)
I/art ( 9495): at void com.android.internal.os.ZygoteInit.main(java.lang.String[]) (ZygoteInit.java:820)
I/art ( 9495): Caused by: java.lang.ClassNotFoundException: Didn't find class "android.view.View$OnUnhandledKeyEventListener" on path: DexPathList[[zip file "/data/app/com.prevent.oncologia-2/base.apk"],nativeLibraryDirectories=[/data/app/com.prevent.oncologia-2/lib/arm64, /data/app/com.prevent.oncologia-2/base.apk!/lib/arm64-v8a, /system/lib64, /vendor/lib64]]
I/art ( 9495): at java.lang.Class dalvik.system.BaseDexClassLoader.findClass(java.lang.String) (BaseDexClassLoader.java:56)
I/art ( 9495): at java.lang.Class java.lang.ClassLoader.loadClass(java.lang.String, boolean) (ClassLoader.java:380)
I/art ( 9495): at java.lang.Class java.lang.ClassLoader.loadClass(java.lang.String) (ClassLoader.java:312)
I/art ( 9495): at void androidx.core.view.ViewCompat.setOnApplyWindowInsetsListener(android.view.View, androidx.core.view.OnApplyWindowInsetsListener) (ViewCompat.java:2421)
I/art ( 9495): at android.view.ViewGroup androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor() (AppCompatDelegateImpl.java:779)
I/art ( 9495): at void androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor() (AppCompatDelegateImpl.java:659)
I/art ( 9495): at void androidx.appcompat.app.AppCompatDelegateImpl.setContentView(int) (AppCompatDelegateImpl.java:552)
I/art ( 9495): at void androidx.appcompat.app.AppCompatActivity.setContentView(int) (AppCompatActivity.java:161)
I/art ( 9495): at void com.shinow.qrscan.SecondActivity.onCreate(android.os.Bundle) (SecondActivity.java:39)
I/art ( 9495): at void android.app.Activity.performCreate(android.os.Bundle) (Activity.java:6854)