CODEWITHSUNDEEP
android
rahul
rahul

Reputation: 2906

java.lang.RuntimeException: Unable to instantiate activity ComponentInfo

I was trying to run a sample code While launching the application in the android 1.5 emulator , I got these errors.... Any one have some hint..?

ERROR from LogCat:

01-13 02:28:08.392: ERROR/AndroidRuntime(2888): FATAL EXCEPTION: main
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.s.android.test/com.s.android.test.MainActivity}: java.lang.ClassNotFoundException: com.s.android.test.MainActivity in loader dalvik.system.PathClassLoader[/data/app/com.s.android.test-2.apk]
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1544)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1638)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:928)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     at android.os.Handler.dispatchMessage(Handler.java:99)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     at android.os.Looper.loop(Looper.java:123)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     at android.app.ActivityThread.main(ActivityThread.java:3647)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     at java.lang.reflect.Method.invokeNative(Native Method)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     at java.lang.reflect.Method.invoke(Method.java:507)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     at dalvik.system.NativeStart.main(Native Method)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888): Caused by: java.lang.ClassNotFoundException: com.s.android.test.MainActivity in loader dalvik.system.PathClassLoader[/data/app/com.s.android.test-2.apk]
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:240)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     at java.lang.ClassLoader.loadClass(ClassLoader.java:551)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1536)
01-13 02:28:08.392: ERROR/AndroidRuntime(2888):     ... 11 more
01-13 02:28:08.407: WARN/ActivityManager(112):   Force finishing activity com.s.android.test/.MainActivity

Edit This error happens to most of the beginners, the thing is that you have to add all your activities in the Manifest file.

Upvotes: 202

Views: 484476

Answers (30)

jasjastone
jasjastone

Reputation: 149

For flutter people, I faced this error after rename my package name using this flutter package change_app_package_name

So the way i fix it by first run flutter clean then run flutter pub get to get packages after that make to make sure you have rename your package correct do a global search(if your in vscode as me just hit Ctrl+Shift+F) of the old package name example the old could be com.organization.example.app and replace it with the new package name example com.organization.app. The most important file that need to be replace is andrioid/app/build.gradle and change the part of the namespace could be like

android {
    namespace "com.organization.app" //<--- Here is where you need to set the new package name
    compileSdkVersion 34

    .....the rest of the config
}

Also there could be another files and Those files that needs to be replaced are just AndroidManifest.xml files either a debug one or profile change the the part where you see the package name then followed by .MainActivity example com.organization.example.app.MainActivity to com.organization.app.MainActivity and your done run the app again but one as for the AndroidManifest.xml on the android/app/src/main folder just leave it as .MainActivity and it will be just fine. Hope it helps

Upvotes: 0

wocmultimedia
wocmultimedia

Reputation: 269

I had the same problem but it happened after I renamed the package. In making the refactor automatically the software removed in the manifest.xml the "com.mycompany." from "com.mycompany.packagename.Main" and it appeared only as "packagename.Main". This happened with all the activities declared into. After reading through the whole answers above I went to compare my manifest.xml against the manifest.xml of another app running perfectly and I discovered this situation. I added "com.mycompany." to all activities and the app run smoothly immediately.

Upvotes: 1

Mohamad El Bohsaly
Mohamad El Bohsaly

Reputation: 77

I faced the same issue while running my Flutter application in debug mode. I managed to solve it via amending the below changes into MainActivity.kt

package com.example.yourappname

import io.flutter.embedding.android.FlutterActivity

class MainActivity: FlutterActivity() {
    // You can add any necessary code or configurations here
}

Upvotes: 1

ramzieus
ramzieus

Reputation: 157

Also check that the package name is the same in android/app/src/main/kotlin/com/.../MainActivity.kt package com.xxxx.xxxx and AndroidManifest.xml package="com.xxxx.xxxx"

Upvotes: 1

Fredrick
Fredrick

Reputation: 81

For flutter applications. Make sure you run flutter clean and flutter pub get after you change the package name.

Upvotes: 0

Amit Singh
Amit Singh

Reputation: 679

Make sure MainActivity is not "abstract".

abstract class MainActivity : AppCompatActivity()

just remove the abstract

class MainActivity : AppCompatActivity() {

Upvotes: 6

apaluk
apaluk

Reputation: 431

My problem was missing package declaration in the beginning of the activity source file:

package com.my.package

Upvotes: 4

manoj kiran
manoj kiran

Reputation: 114

In my case I forget to make MainActivity class as public.

Other solutions:

  1. Add activity in Manifest file

  2. Verify all access modifiers

Upvotes: 3

Brian Reinhold
Brian Reinhold

Reputation: 2475

Whow are there lots of ways to get this error!.

I will add another given none of the others either applied or were the cause.

I forgot the 'public' in the declaration of my activity class! It was package private.

I had been writing so much Bluetooth code that habit caused me to create an activity class that was package private.

Says something about the obscurity of this error message.

Upvotes: 3

Thriveni
Thriveni

Reputation: 771

For me it was different from any of the above,

The activity was declared as abstract, That is why giving the error. Once it removed it worked.

Earlier

     public abstract class SampleActivity extends AppcompatActivity{
     }

After removal

     public class SampleActivity extends AppcompatActivity{
     }

Upvotes: 6

Ritesh Khandekar
Ritesh Khandekar

Reputation: 4015

This also happens when you type the wrong applicationId in the build.gradle file.

For eg. Your application ID is com.example.myapp.app

And you wrote build.gradle file like this:

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.1"

    defaultConfig {
        applicationId "com.example.myapp"
        //this will make your app crash so write exact applicationId as it is
        minSdkVersion 8
        targetSdkVersion 8
    }

Upvotes: 3

Anup H
Anup H

Reputation: 549

In my case, I was trying to initialize the components(UI) even before the onCreate is called for the Activity.

Make sure your UI components are initialized/linked in the onCreate method after setContentView

NB: This is my first mistake while learning Android programming.

Upvotes: 5

Karthik Kompelli
Karthik Kompelli

Reputation: 2214

Don't do like this

ImageView imageView=findViewById(R.id.imageView);
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

Do it like this 

ImageView imageView;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    imageView=findViewById(R.id.imageView);

Upvotes: 0

Igor
Igor

Reputation: 2089

Sometimes isMinifyEnabled = false may help (make sure you clean the project before launch)

Upvotes: 0

Sagar Jethva
Sagar Jethva

Reputation: 1014

I have tried all above solution but nothing work for me. after I have just add extend activity instead of AppCompatActivity and working fine.

used

public class MainActivity extends Activity

instead of

public class MainActivity extends AppCompatActivity

i dont know what real issue was that.

Upvotes: 1

Shailendra Madda
Shailendra Madda

Reputation: 21561

As suggested by djjeck in comment in this answer I missed to put public modifier for my class.

It should be

public class MyActivity extends AppCompatActivity {

It may help some like me.

Upvotes: 2

hexicle
hexicle

Reputation: 2187

If you have Android Studio 2.3.3 and Android Studio 3.0.0 installed, then switching between the two programs for development will cause this error. This is because there exist situations where classes supported in one program is not supported by the other and vice versa. It is important to maintain consistency in which version of Android Studio is being used to develop a project.

Upvotes: 1

Muz
Muz

Reputation: 5980

This might not be relevant to the actual question, but in my instance, I tried to implement Kotlin and left out apply plugin: 'kotlin-android'. The error happened because it could not recognize the MainActivity in as a .kt file.

Hope it helps someone.

Upvotes: 33

Eames
Eames

Reputation: 319

In my case, I had to add a new Android 6.0 Library by going to Window >> Preferences >> Java >> Build Path >> User Libraries >> Add Library >> User Library >> New

Name it Android 6.0, then click OK. After that, add the android.jar file that you can find in "sdklocation/platforms/android-23/android.jar"

Make sure you do all this in the Android project.

Upvotes: 0

Menelaos Kotsollaris
Menelaos Kotsollaris

Reputation: 5506

In my case, I was trying to embed the Facebook SDK and I was having the wrong Application ID; thus the error was popping up. In your manifest file, you should have the proper meta data:

<meta-data
android:name="com.facebook.sdk.ApplicationId"
android:value="@string/facebook_app_id" />

Upvotes: 1

Sdembla
Sdembla

Reputation: 1707

I had the same issue (Unable to instantiate Activity) :

FIRST reason :

I was accessing

Camera mCamera;
Camera.Parameters params = mCamera.getParameters();

before 

mCamera = Camera.open();

So right way of doing is, open the camera first and then access parameters.

SECOND reason : Declare your activity in the manifest file 

<activity android:name=".activities.MainActivity"/>

THIRD reason : Declare Camera permission in your manifest file.

<uses-feature android:name="android.hardware.Camera"></uses-feature>
<uses-permission android:name="android.permission.CAMERA" />

Hope this helps

Upvotes: 1

Satthy
Satthy

Reputation: 119

This can happen if your activity class is inside a default package. I fixed it by moving the activity class to a new package. and changing the manifest.xml

before

activity android:name=".MainActivity"

after

activity android:name="new_package.MainActivity"

Upvotes: 3

Swapnil Kotwal
Swapnil Kotwal

Reputation: 5728

Most the time If Activity name changed reflected all over the project except the AndroidManifest.xml file.

You just need to Add the name in manifest manually.

<activity
android:name="Activity_Class_Name"
android:label="@string/app_name">
</activity>

Upvotes: 1

Tanmay Mandal
Tanmay Mandal

Reputation: 40188

It is a problem of your Intent.

Please add your Activity in your AndroidManifest.xml.

When you want to make a new activity, you should register it in your AndroidManifest.xml.

Upvotes: 182

SMUsamaShah
SMUsamaShah

Reputation: 7890

You may be trying to find the view before onCreate() which is incorrect.

public class MainActivity extends Activity {

  ImageView mainImage = (ImageView) findViewById(R.id.imageViewMain); //incorrect

  @Override
  protected void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
  }
  ...
}

Upvotes: 77

satyrFrost
satyrFrost

Reputation: 413

For me, my package string in AndroidManifest.xml was incorrect (copied from a tutorial). Make sure the package string in this file is the same as where your main activity is, e.g.

 package="com.example.app"

An easy way to do this is to open the AndroidManifest.xml file in the "Manifest" tab, and type it in the text box next to Package, or use the Browse button.

Also, the package string for my activity was wrong, e.g.

<activity android:name="com.example.app.MainActivity" android:label="@string/app_name">

I (stupidly) got the same error weeks later when I renamed my package name. If you do this, make sure you update the AndroidManifest.xml file too.

Upvotes: 8

Emran Hamza
Emran Hamza

Reputation: 3869

Simply Clean your working project or restart eclipse. Then run your project. it will work.

Upvotes: 7

ryaliscs
ryaliscs

Reputation: 123

In my case I had two version of "android-support-v4.jar" references in the project. After resolving this (removed additional/incorrect reference) solved the issue.

Upvotes: 0

nikhilgotan
nikhilgotan

Reputation: 112

Right click on project > properties > android > and try with different version of the android earlier i was doing with android 4.4 then i changed to android 4.3 and it worked !

Upvotes: 1

Sash_KP
Sash_KP

Reputation: 5591

Also if you're retrieving something from intent of another activity using getIntent in the current activity and setting those retrieved data before/above onCreate then this exception is thrown.

For eg. if i retrieve a string like this 

final String slot1 = getIntent().getExtras().getString("Slot1");

and put this line of code before/above onCreate then this exception is thrown.

Upvotes: 0

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