Develop Reference

findviewbyid() Causing Runtime Exception

Command line
val /*Variable Name*/ = findviewbyid<ImageButton>(R.id./*id*/)
Causing runtime error in Emulator running Android 11
Error Log:
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.cobalt.coffetra/com.cobalt.coffetra.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.ApplicationInfo android.content.Context.getApplicationInfo()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3365)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.ApplicationInfo android.content.Context.getApplicationInfo()' on a null object reference
at android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:173)
at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:174)
at android.content.Context.obtainStyledAttributes(Context.java:744)
at androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor(AppCompatDelegateImpl.java:852)
at androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor(AppCompatDelegateImpl.java:819)
at androidx.appcompat.app.AppCompatDelegateImpl.findViewById(AppCompatDelegateImpl.java:640)
at androidx.appcompat.app.AppCompatActivity.findViewById(AppCompatActivity.java:261)
at com.cobalt.coffetra.MainActivity.<init>(MainActivity.kt:81)
at java.lang.Class.newInstance(Native Method)
at android.app.AppComponentFactory.instantiateActivity(AppComponentFactory.java:95)
at androidx.core.app.CoreComponentFactory.instantiateActivity(CoreComponentFactory.java:45)
at android.app.Instrumentation.newActivity(Instrumentation.java:1253)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3353)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601) 
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85) 
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066) 
at android.os.Handler.dispatchMessage(Handler.java:106) 
at android.os.Looper.loop(Looper.java:223) 
at android.app.ActivityThread.main(ActivityThread.java:7656) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947) 
Tried changing Gradle Version, but did not work

Ionic android application crashes instantly

I am making this post today because I have a problem with my ionic application.
So here it is, the app builds perfectly on an emulator with android studio. However, right after the splash screen it crashes instantly. I have no idea why this is happening. After running the app in debug mode, I get this error:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.julesbsz.shortnews, PID: 862
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.julesbsz.shortnews/com.julesbsz.shortnews.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'int org.json.JSONArray.length()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3270)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int org.json.JSONArray.length()' on a null object reference
at com.codetrixstudio.capacitor.GoogleAuth.GoogleAuth.load(GoogleAuth.java:47)
at com.getcapacitor.PluginHandle.load(PluginHandle.java:72)
at com.getcapacitor.PluginHandle.<init>(PluginHandle.java:44)
at com.getcapacitor.Bridge.registerPlugin(Bridge.java:476)
at com.getcapacitor.Bridge.registerAllPlugins(Bridge.java:440)
at com.getcapacitor.Bridge.<init>(Bridge.java:170)
at com.getcapacitor.BridgeActivity.load(BridgeActivity.java:83)
at com.getcapacitor.BridgeActivity.init(BridgeActivity.java:62)
at com.getcapacitor.BridgeActivity.init(BridgeActivity.java:48)
at com.julesbsz.shortnews.MainActivity.onCreate(MainActivity.java:17)
at android.app.Activity.performCreate(Activity.java:7802)
at android.app.Activity.performCreate(Activity.java:7791)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1299)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3245)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409) 
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016) 
at android.os.Handler.dispatchMessage(Handler.java:107) 
at android.os.Looper.loop(Looper.java:214) 
at android.app.ActivityThread.main(ActivityThread.java:7356) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930) 
Disconnected from the target VM, address: 'localhost:8600', transport: 'socket'
I really don't see what the problem is. Also, if you need more information about something in particular, let me know. Thank you very much.

If you read the stacktrace you can see that the crash originates from
at com.julesbsz.shortnews.MainActivity.onCreate(MainActivity.java:17)
It then appears to fail at some authorization logic
at com.codetrixstudio.capacitor.GoogleAuth.GoogleAuth.load(GoogleAuth.java:47)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int org.json.JSONArray.length()' on a null object reference
You did not post your code so perhaps this is a good time to learn how to set breakpoints and debug?
https://developer.android.com/studio/debug#breakPoints

Failed to build in android studio. Can't find why it's not working [duplicate]

This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 1 year ago.
at first when I started the app the error sad "unable to delete directory" so i delete that file. The virtual devices started but the app keep stopping and I can't find why.
Process: com.example.library, PID: 10926
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.library/com.example.library.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3449)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at com.example.library.MainActivity.onCreate(MainActivity.java:20)
at android.app.Activity.performCreate(Activity.java:8000)
at android.app.Activity.performCreate(Activity.java:7984)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1309)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3422)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601) 
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85) 
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066) 
at android.os.Handler.dispatchMessage(Handler.java:106) 
at android.os.Looper.loop(Looper.java:223) 
at android.app.ActivityThread.main(ActivityThread.java:7656) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
this is the error when i start the app

A Button in the MainActivity line 20 is not be inited.
you should init the button by :
Button btn = (Button)findViewById(R.id.btn);
Before use btn.serOnClickListener...

Android Application is crashing in debug mode working fine in release mode

Description: I didn't make any changes to my code.
This issue is reproducing for both 4.1.1 and 4.4.0 Gradle versions
App crashing in debug mode but working fine in Release mode.
I tried reinstalling the android studio Nothing helps me
Android API version: Android API version Android 11 (30 )
Material Library version: com.google.android.material:material:1.2.1
Device: Pixel 3a
Reproducing for all Material components Bottom sheet dialog, Bottom navigation view
https://www.loom.com/share/e2347984737d4988b257a584ada13acb
https://github.com/material-components/material-components-android/issues/1877
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at com.google.android.material.bottomsheet.BottomSheetDialog.wrapInBottomSheet(BottomSheetDialog.java:216)
at com.google.android.material.bottomsheet.BottomSheetDialog.setContentView(BottomSheetDialog.java:93)
at androidx.fragment.app.DialogFragment.onActivityCreated(DialogFragment.java:504)
at com.rizek.android.users.views.bottomsheet.ExpandedBottomSheetFragment.onActivityCreated(ExpandedBottomSheetFragment.kt:28)
at androidx.fragment.app.Fragment.performActivityCreated(Fragment.java:2718)
at androidx.fragment.app.FragmentStateManager.activityCreated(FragmentStateManager.java:346)
at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1200)
at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1368)
at androidx.fragment.app.FragmentManager.moveFragmentToExpectedState(FragmentManager.java:1446)
at androidx.fragment.app.FragmentManager.moveToState(FragmentManager.java:1509)
at androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:447)
at androidx.fragment.app.FragmentManager.executeOps(FragmentManager.java:2181)
at androidx.fragment.app.FragmentManager.executeOpsTogether(FragmentManager.java:2004)
at androidx.fragment.app.FragmentManager.removeRedundantOperationsAndExecute(FragmentManager.java:1959)
at androidx.fragment.app.FragmentManager.execPendingActions(FragmentManager.java:1861)
at androidx.fragment.app.FragmentManager.dispatchStateChange(FragmentManager.java:2641)
at androidx.fragment.app.FragmentManager.dispatchActivityCreated(FragmentManager.java:2589)
at androidx.fragment.app.FragmentController.dispatchActivityCreated(FragmentController.java:247)
at androidx.fragment.app.FragmentActivity.onStart(FragmentActivity.java:541)
at androidx.appcompat.app.AppCompatActivity.onStart(AppCompatActivity.java:210)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1435)
at android.app.Activity.performStart(Activity.java:8024)
at android.app.ActivityThread.handleStartActivity(ActivityThread.java:3475)
at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:221)
at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:201)
at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:173)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
android.view.InflateException: Binary XML file line #38 in com.rizek.android.users.test:layout/activity_dashboard: Binary XML file line #38 in com.rizek.android.users.test:layout/activity_dashboard: Error inflating class com.google.android.material.bottomnavigation.BottomNavigationView at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3449) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601) at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85) at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066) at android.os.Handler.dispatchMessage(Handler.java:106) at android.os.Looper.loop(Looper.java:223) at android.app.ActivityThread.main(ActivityThread.java:7656) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947) Caused by: android.view.InflateException: Binary XML file line #38 in com.rizek.android.users.test:layout/activity_dashboard: Binary XML file line #38 in com.rizek.android.users.test:layout/activity_dashboard: Error inflating class com.google.android.material.bottomnavigation.BottomNavigationView Caused by: android.view.InflateException: Binary XML file line #38 in com.rizek.android.users.test:layout/activity_dashboard: Error inflating class com.google.android.material.bottomnavigation.BottomNavigationView Caused by: java.lang.reflect.InvocationTargetException at java.lang.reflect.Constructor.newInstance0(Native Method) at java.lang.reflect.Constructor.newInstance(Constructor.java:343) at android.view.LayoutInflater.createView(LayoutInflater.java:852) at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:1004) at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:959) at android.view.LayoutInflater.rInflate(LayoutInflater.java:1121) at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1082) at android.view.LayoutInflater.rInflate(LayoutInflater.java:1124) at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1082) at android.view.LayoutInflater.inflate(LayoutInflater.java:680) at android.view.LayoutInflater.inflate(LayoutInflater.java:532) at android.view.LayoutInflater.inflate(LayoutInflater.java:479) at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:696) at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:170) at androidx.databinding.DataBindingUtil.setContentView(DataBindingUtil.java:303) at androidx.databinding.DataBindingUtil.setContentView(DataBindingUtil.java:284) at com.rizek.android.users.base.BaseActivity.performDataBinding(BaseActivity.kt:370) at com.rizek.android.users.base.BaseActivity.onCreate(BaseActivity.kt:223) at com.rizek.android.users.ui.dashboard.DashboardActivity.onCreate(DashboardActivity.kt:79) at android.app.Activity.performCreate(Activity.java:8000) at android.app.Activity.performCreate(Activity.java:7984) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1309) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3422) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601) at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85) at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 2020-11-18 13:36:59.578 7372-7372/com.rizek.android.users.test E/AndroidRuntime: at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066) at android.os.Handler.dispatchMessage(Handler.java:106) at android.os.Looper.loop(Looper.java:223) at android.app.ActivityThread.main(ActivityThread.java:7656) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947) Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.view.View.setImportantForAccessibility(int)' on a null object reference at androidx.core.view.ViewCompat.setImportantForAccessibility(ViewCompat.java:1119) at com.google.android.material.bottomnavigation.BottomNavigationItemView.<init>(BottomNavigationItemView.java:104) at com.google.android.material.bottomnavigation.BottomNavigationItemView.<init>(BottomNavigationItemView.java:87) at com.google.android.material.bottomnavigation.BottomNavigationItemView.<init>(BottomNavigationItemView.java:83) at com.google.android.material.bottomnavigation.BottomNavigationMenuView.getNewItem(BottomNavigationMenuView.java:606) at com.google.android.material.bottomnavigation.BottomNavigationMenuView.buildMenuView(BottomNavigationMenuView.java:538) at com.google.android.material.bottomnavigation.BottomNavigationPresenter.updateMenuView(BottomNavigationPresenter.java:67) at com.google.android.material.bottomnavigation.BottomNavigationView.inflateMenu(BottomNavigationView.java:344) at com.google.android.material.bottomnavigation.BottomNavigationView.<init>(BottomNavigationView.java:226) at com.google.android.material.bottomnavigation.BottomNavigationView.<init>(BottomNavigationView.java:133) ... 34 more

android studio crash log explanation [duplicate]

This question already has answers here:
Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference
(2 answers)
Why does my Android app crash with a NullPointerException when initializing a variable with findViewById(R.id.******) at the beginning of the class?
(9 answers)
Closed 4 years ago.
my android app is crashing when i get to an activity named "finalizar" and I dont understand the crash log.
this activity is kind of the leaderboard (dunno if that helps)
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.nico.quimiquiz, PID: 1198
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.nico.quimiquiz/com.example.nico.quimiquiz.finalizar}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2679)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:440)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.Window$Callback android.view.Window.getCallback()' on a null object reference
at android.support.v7.app.AppCompatDelegateImplBase.<init>(AppCompatDelegateImplBase.java:117)
at android.support.v7.app.AppCompatDelegateImplV9.<init>(AppCompatDelegateImplV9.java:149)
at android.support.v7.app.AppCompatDelegateImplV14.<init>(AppCompatDelegateImplV14.java:56)
at android.support.v7.app.AppCompatDelegateImplV23.<init>(AppCompatDelegateImplV23.java:31)
at android.support.v7.app.AppCompatDelegateImplN.<init>(AppCompatDelegateImplN.java:31)
at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:198)
at android.support.v7.app.AppCompatDelegate.create(AppCompatDelegate.java:183)
at android.support.v7.app.AppCompatActivity.getDelegate(AppCompatActivity.java:519)
at android.support.v7.app.AppCompatActivity.findViewById(AppCompatActivity.java:190)
at com.example.nico.quimiquiz.finalizar.<init>(finalizar.java:93)
at java.lang.Class.newInstance(Native Method)
at android.app.Instrumentation.newActivity(Instrumentation.java:1175)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2669)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856) 
at android.app.ActivityThread.-wrap11(Unknown Source:0) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589) 
at android.os.Handler.dispatchMessage(Handler.java:106) 
at android.os.Looper.loop(Looper.java:164) 
at android.app.ActivityThread.main(ActivityThread.java:6494) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:440) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)