I decided to modify the old project for the new versions android 7.8. The project was opened in android studio 3.0 - I tweaked the project for android studio 3.0, the project is assembled and compiled without errors, but when I run the apk file on the device. This error is written to the log:

01 - 12 01: 47: 22.910 1811 - 1811 / ? E / AndroidRuntime : FATAL EXCEPTION: main Process: com.android.locktest.lockscreen, PID: 1811 java.lang.RuntimeException: Unable to instantiate activity ComponentInfo { com.android.locktest.lockscreen / com.screen.locktest.lockscreen.LockScreenActivity }: java.lang.InstantiationException: class com.screen.locktest.lockscreen.LockScreenActivity cannot be instantiated at android.app.ActivityThread.performLaunchActivity(ActivityThread.java: 2209) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java: 2360) at android.app.ActivityThread.access$800(ActivityThread.java: 144) at android.app.ActivityThread$H.handleMessage(ActivityThread.java: 1278) at android.os.Handler.dispatchMessage(Handler.java: 102) at android.os.Looper.loop(Looper.java: 135) at android.app.ActivityThread.main(ActivityThread.java: 5221) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java: 372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java: 899) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java: 694) Caused by: java.lang.InstantiationException: class com.screen.locktest.lockscreen.LockScreenActivity cannot be instantiated at java.lang.Class.newInstance(Class.java: 1553) at android.app.Instrumentation.newActivity(Instrumentation.java: 1065) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java: 2199) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java: 2360) at android.app.ActivityThread.access$800(ActivityThread.java: 144) at android.app.ActivityThread$H.handleMessage(ActivityThread.java: 1278) at android.os.Handler.dispatchMessage(Handler.java: 102) at android.os.Looper.loop(Looper.java: 135) at android.app.ActivityThread.main(ActivityThread.java: 5221) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java: 372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java: 899) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java: 694) 01 - 12 01: 57: 49.896 2089 - 2089 / com.android.locktest.lockscreen E / AndroidRuntime: FATAL EXCEPTION: main Process: com.android.locktest.lockscreen, PID: 2089 java.lang.RuntimeException: Unable to instantiate activity ComponentInfo { com.android.locktest.lockscreen / com.screen.locktest.lockscreen.LockScreenActivity }: java.lang.InstantiationException: class com.screen.locktest.lockscreen.LockScreenActivity cannot be instantiated at android.app.ActivityThread.performLaunchActivity(ActivityThread.java: 2209) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java: 2360) at android.app.ActivityThread.access$800(ActivityThread.java: 144) at android.app.ActivityThread$H.handleMessage(ActivityThread.java: 1278) at android.os.Handler.dispatchMessage(Handler.java: 102) at android.os.Looper.loop(Looper.java: 135) at android.app.ActivityThread.main(ActivityThread.java: 5221) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java: 372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java: 899) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java: 694) Caused by: java.lang.InstantiationException: class com.screen.locktest.lockscreen.LockScreenActivity cannot be instantiated at java.lang.Class.newInstance(Class.java: 1553) at android.app.Instrumentation.newActivity(Instrumentation.java: 1065) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java: 2199) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java: 2360) at android.app.ActivityThread.access$800(ActivityThread.java: 144) at android.app.ActivityThread$H.handleMessage(ActivityThread.java: 1278) at android.os.Handler.dispatchMessage(Handler.java: 102) at android.os.Looper.loop(Looper.java: 135) at android.app.ActivityThread.main(ActivityThread.java: 5221) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java: 372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java: 899) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java: 694)

I understand the error lies here, but I do not know how to fix it.

 java.lang.RuntimeException: Unable to instantiate activity ComponentInfo { com.android.locktest.lockscreen / com.screen.locktest.lockscreen.LockScreenActivity }: java.lang.InstantiationException: class com.screen.locktest.lockscreen.LockScreenActivity cannot be instantiated

Here is the manifest:

 << ? xml version = "1.0" encoding = "utf-8" ? > < manifest xmlns : android = "http://schemas.android.com/apk/res/android" xmlns: tools = "http://schemas.android.com/tools" package = "com.android.locktest.lockscreen" tools: ignore = "ExtraText" > < uses - permission android: name = "android.permission.DISABLE_KEYGUARD" / > < uses - permission android: name = "android.permission.WAKE_LOCK" / > < uses - permission android: name = "android.permission.RECEIVE_BOOT_COMPLETED" / > < uses - permission android: name = "android.permission.READ_PHONE_STATE" / > < uses - permission android: name = "android.permission.SYSTEM_ALERT_WINDOW" / > < application android: label = "@string/app_name" android: name = "android.support.multidex.MultiDexApplication" > < activity android: name = "com.screen.locktest.lockscreen.LockScreenActivity" android: excludeFromRecents = "true" android: label = "@string/app_name" android: launchMode = "singleTask" android: screenOrientation = "portrait" android: theme = "@android:style/Theme.NoTitleBar.Fullscreen" > < intent - filter > < action android: name = "android.intent.action.MAIN" / > < category android: name = "android.intent.category.LAUNCHER" / > < /intent-filter> < /activity> < service android: name = "com.screen.locktest.lockscreen.LockscreenService" / > < receiver android: name = "com.screen.locktest.lockscreen.LockscreenIntentReceiver" > < intent - filter > < action android: name = "android.intent.action.BOOT_COMPLETED" / > < /intent-filter> < /receiver> < /application> < /manifest>

Here is the build.Gradle file

 apply plugin: 'com.android.application' android { aaptOptions.cruncherEnabled = false aaptOptions.useNewCruncher = false compileSdkVersion 27 buildToolsVersion '26.0.2' defaultConfig { multiDexEnabled true minSdkVersion 19 targetSdkVersion 27 } buildTypes { release { minifyEnabled false proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' } } compileOptions { targetCompatibility 1.8 sourceCompatibility 1.8 } } dependencies { implementation 'com.android.support:multidex:1.0.2' implementation 'com.android.support:appcompat-v7:27.0.2' implementation 'com.android.support.constraint:constraint-layout:1.0.2' testImplementation 'junit:junit:4.12' androidTestImplementation 'com.android.support.test:runner:1.0.1' androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1' }

Help me please.

  • Try to disable proguard. He is a reflection with a bad friend. Caused by: java.lang.InstantiationException: class com.screen.locktest.lockscreen.LockScreenActivity cannot be instantiated at java.lang.Class.newInstance(Class.java: 1553) - rjhdby
  • Well, proguard is disabled: buildTypes {release {minifyEnabled false proguardFiles getDefaultProguardFile ('proguard-android.txt'), 'proguard-rules.pro'}} - Mike Nemsky
  • It seems that the new operator is called to activate, which is wrong. - lampa
  • Here is this project: github.com/Joisar/LockScreenApp/tree/master/LockScreenApp - Mike Nemsky
  • Check the package names of LockScreenActivity - whether the package is the same in the class itself, the name of the package in which it lies and the name with which it is specified in the manifest. - woesss

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