Default Activity Not Found - Bug in Android Studio 3.3

Question

When I create a new project in Android Studio 3.3, it shows an error at Run -> Edit Configurations saying

default activity is not found.

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity">

    <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Hello World!"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent"/>

</android.support.constraint.ConstraintLayout>

This is my activity_main.xml file. It shows an error in line

tools:context=".MainActivity"

saying

Unresolved Class MainActivity

Here is my AndroidManifest.xml file - everything seems to be all right here -

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="com.example.android.myapplication">

<application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN"/>

            <category android:name="android.intent.category.LAUNCHER"/>
        </intent-filter>
    </activity>
</application>

</manifest>

The files colors.xml , ic_launcher_background.xml, and ic_launcher_foreground.xml are not correctly formed, and look something like this -

        f

        isInitialized
        kotlin
        Boolean
        reflect

        KProperty0
        SinceKotlin
        version
        1.2
        internal

        InlineOnly0






             4"  8�H PX��     (�    �

I tried to Clean and Rebuild project, which gave an error saying

colors.xml is not formed properly.

I tried File -> Invalidate Caches/Restart, but it still shows the same error.

This problem started one day after updating Android Studio 3.2.1 to Android Studio 3.3. It worked all fine the first day, but when I tried run an app on the second day, it started showing this error saying Default Activity not found.

Is there any way to fix this issue and continue using Android Studio version 3.3?

EDIT -

Yay! As @Andreas suggested, my Android Studio itself could've been corrupted, and works all right after uninstalling and reinstalling the same version (I did not even revert to an older version). Should check if this problem might repeat again in a few days.

EDIT 2-

I'm viewing this after an year and I'm happy it has helped a lot of people. Turns out this problem can arise due to various issues, and there's no one perfect answer for this. So check all the answers and see if something works for you if you're facing the same problem :)

Your current project files got corrupted, i think you should create a new project and try. — MadLeo, Jan 23 '19 at 04:09
I tried creating a new project many times. The files get corrupted and I get the same error every time. — Umesh Konduru, Jan 23 '19 at 04:13
Then your Android Studio itself might be corrupted. You might need to do a fresh install on that — Andreas, Jan 23 '19 at 04:15
then revert your android studio to previous version i.e. 3.2.1 or reinstall studio as @Andreas suggested — MadLeo, Jan 23 '19 at 04:15
You mean I have to uninstall it and install it again? And which version should I install - 3.2.1 or 3.3? — Umesh Konduru, Jan 23 '19 at 04:18
install 3.2.1 and then make a copy of that and upgrade copy to 3.3 to see if error persists. never upgrade your primary dev environment to incremental releases unless you face breaking issues or really need a new feature — Karan Harsh Wardhan, Jan 23 '19 at 05:35
@KaranHarshWardhan , I had some problems with 3.2.1 has gradle build was facing some issues. I found upgrading Android Studio as a solution and my problems was solved. Then, a day later, this problem started, but as suggested in the edit, Andreas's solution worked — Umesh Konduru, Jan 23 '19 at 06:23
@PratikButani , it is in res/values . Anyway, the problem is now solved. — Umesh Konduru, Jan 23 '19 at 06:24
@UmeshKonduru can you theorize about why it might have been corrupted? also add an answer and accept it yourself — Karan Harsh Wardhan, Jan 23 '19 at 07:13
I'm a beginner and I've got no idea about why it could've been corrupted. — Umesh Konduru, Jan 23 '19 at 09:01

score 13 · Answer 1 · answered Jan 23 '20 at 07:42

13

After searching a lot this is what worked for me,

Go to Edit Configuration -> Select your Application Module -> Under Launch Options -> Select Nothing from Launch drop down.

(Refer image for better reference)

answered Jan 23 '20 at 07:42

Astha Garg

1,022
7
21

score 12 · Answer 2 · answered Jan 23 '19 at 06:36

12

Close the project and Delete Cache folder inside your C:\Users\UserName\.AndroidStudio3.3 folder and Build your project.

answered Jan 23 '19 at 06:36

Sabyasachi

3,499
2
14
21

4

Caches folder is located in C:\Users\UserName\.AndroidStudio3.3\system folder in my PC – Faraz Ahmed Jun 15 '19 at 05:03
1

I have same issue. i updated android studio to 4.0. cleaned project, invalidate restart and sync project not worked for me. – Nitish Jun 08 '20 at 06:53
Yeah, I believe deleting this `caches` dir is the same as selecting *Invalidate Caches / Restart* from within Android Studio – Sterling Aug 09 '20 at 16:27
1

@String This answer worked for me, but _Invalidate Caches / Restart_ did not. A test demonstrates that _Invalidate Caches_ does not clear out the contents of the "system/caches" folder. – greeble31 Sep 27 '20 at 22:26

score 4 · Answer 3 · answered Jul 18 '19 at 18:36

4

I had the same problem with version 3.4. Goto Build -> Edit Build Types -> SDK location and checked Use embedded JDK (recommended). It worked fine.

answered Jul 18 '19 at 18:36

Njinga TCHAPTCHET

41
1

score 2 · Answer 4 · answered Jan 23 '19 at 04:25

2

Restart your android studio with option Invalidate Caches/Restart. You can find this option under file option. I think it will work for you.

answered Jan 23 '19 at 04:25

RANAJEET BARIK

185
2
7

score 2 · Accepted Answer · answered Jan 23 '19 at 09:02

2

There is a chance that Android Studio itself could've been corrupted. Uninstalling and Reinstalling Android Studio solves the problem.

answered Jan 23 '19 at 09:02

Umesh Konduru

361
1
6
19

score 2 · Answer 6 · answered Nov 11 '19 at 17:33

In Android Studio 3.5.2 my custom launcher/custom home app is getting this error. I was able to reproduce it by creating a brand new blank activity app, then replacing

     <category android:name="android.intent.category.LAUNCHER"/>

with

     <category android:name="android.intent.category.DEFAULT" />
     <category android:name="android.intent.category.HOME" />

in the manifest. That single change causes Android Studio to lose track of the default activity. I'm able to continue debugging by specifying the activity in the Run/Debug configurations.

I didn't read this carefully enough and thought it was saying you need the `DEFAULT` and `HOME` entries but it is saying you need `LAUNCHER` now — Jim W, Jul 02 '20 at 19:29

score 1 · Answer 7 · answered Jan 15 '20 at 14:34

1

I only had to remove my Gradle cache folder. On Mac this is located in ~/.gradle/caches

answered Jan 15 '20 at 14:34

dell116

5,835
9
52
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score 1 · Answer 8 · answered Feb 11 '20 at 20:51

1

Run/Debug Configurations

AndroidApp > app > General

Module: app
Deploy: Default APK
Launch: Default Activity

GL

answered Feb 11 '20 at 20:51

Braian Coronel

22,105
4
57
62

score 1 · Answer 9 · edited Apr 10 '20 at 00:21

1

With Android Studio 3.6.2 this situation can arise with gradle updates. I found adding rootProject.name='YourAppName' above include ':app' in the settings.gradle file will resolve this issue once you invalidate the caches and restart Android studio, or close out the app and Android Studio and then restart them.

edited Apr 10 '20 at 00:21

shizhen

12,251
9
52
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answered Apr 09 '20 at 21:55

Charles Wehrenberg

46
5

score 1 · Answer 10 · answered Jan 19 '21 at 09:22

1

You might have picked the wrong module from the picker to run the app. Try running your main module which contains the main activity.

answered Jan 19 '21 at 09:22

luckysing_noobster

1,933
5
24
50

score 1 · Answer 11 · edited Jan 22 '21 at 10:08

1

I faced similar problem and the reason was in Manifest merging. There was an error, so it wasn't merged correctly. After solving that error everything goes right.

To check if there are errors while merging go to your AndroidManifest.xml and tap Merged Manifest tab. There would be "Merging Errors"

See this screenshot

edited Jan 22 '21 at 10:08

Sourcerer

1,891
1
19
32

answered Jan 22 '21 at 07:43

Palina Manenok

11
2

score 1 · Answer 12 · answered May 16 '22 at 07:23

Android Studio Chipmunk | 2021.2.1

Edit Configurations ...

Launch Options:

replace "Default Activity" by "Nothing"
Run app (worked!) Launch Options again:
Replace "Nothing" again by "Default Activity"
Run app (terminate running app)

helped for me.

score 0 · Answer 13 · answered Aug 09 '20 at 17:15

None of the other solutions here worked for me, but this error went away after I added the following to my app module's build.gradle file (chasing a different problem):

android {
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

Worth a try, anyway.

Default Activity Not Found - Bug in Android Studio 3.3

13 Answers13

Run/Debug Configurations

Linked