Develop Reference

Could not identify launch Activity: Default Activity not found

I'm new to android and I have encounterded a problem.
The console said that "Could not identify launch activity: Default Activity not found".
I have add
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
in manifests.
And I have tried Invalidate caches/Restart,still not worked.
And the class file which contains the main activity turn green in android studio. I don't know what that means.
This is my manifests file.
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.mrrobot.mycoolweather" >
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme" >
<Activity android:name="com.example.mrrobot.mycoolweather.activity.ChooseAreaActivity"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</Activity>
</application>
</manifest>
The chooseAreaActivity is the one I want to use as launcher activity.

For main activity in your manifest you have to add this with category LAUNCHER (First Activity on launch app):
<activity
android:name=".MainActivity"
android:label="YourAppName"
android:theme="#style/AppTheme.NoActionBar" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
For other activity you have to change category to DEFAULT:
<activity
android:name=".OtherActivity"
android:theme="#style/AppTheme.NoActionBar" >
<intent-filter>
<action android:name="package.OtherActivity" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
Check this Activity and this Start Another Activity
So your code is:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.mrrobot.mycoolweather" >
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme" >
<activity
android:name=".activity.ChooseAreaActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>

Although the question is kind of outdated, I would add the following to all the given answers:
For multi-module projects check carefully that you modify the Manifest corresponding to the Configuration you are trying to run.
Had the same problem and spent 20 minutes just to discover that I was trying to run wrong configuration (with an Application in ModulbeB, while thinking that I was running one from ModuleA).
And sometimes you are working on other module default runnable module changes so you have to change it.

Sometimes it is solved just restarting Android Studio
I had the "Default Activity not found" problem a couple of times and I could solved restarting my android Studio.

If you see that error occur after upgrading your IDEA, upgrading Android Studio version, or Generating a new APK, you may need to refresh the IDE's cache.
File -> Invalidate Caches / Restart...

In your manifest file there was wrong element name (Activity change to activity) declared
<Activity android:name="com.example.mrrobot.mycoolweather.activity.ChooseAreaActivity"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</Activity>
Change it to:
<activity android:name="com.example.mrrobot.mycoolweather.activity.ChooseAreaActivity"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>

When I upgraded Android Studio to 2021.1.1.23 somehow my Run Configuration was switched from app to models, producing this error. Switching back to app resolved the issue for me.

i had these issues with my project:
Default activity not found
xml intellisense was not working
kotlin standard functions were not detecting
All my above issues were resolved by Deleting System cache of Android Studio 3.3 at the home path, and it's working nicely for me,,
Steps:
exit Android Studio
Go to path > C:\Users\YOUR_WINDOW_USER_NAME.AndroidStudio3.3\system
Then you have a \caches folder, delete this caches folder
Now open Android Studio and load your project
Worked for me.. i wasted couple of hours resolving this issue and finally it got resolved in this way.

Exit your android studio IDE. Then locate the "caches" folder in .AndroidStudio3.2 folder.
Location
C:\Users\YOUR_USERNAME\.AndroidStudio3.2\system\caches
For example.
Let's assume say YOUR_USERNAME is called Admin.
C:\Users\Admin\.AndroidStudio3.2\system\caches
Delete the caches folder and start your android studio IDE.

I have tried solutions here and other questions
clean & rebuild & invalidate and restart
make sure that activity has LAUNCHER as category
delete Android cache folder
at End, activity tag was has <activity android:name="com.exmaple.todo.MainActivity" />
when i changed it to <activity android:name=".MainActivity" /> app worked.
I hope it help you if other solution not work.

If your activity is in a different module (e.g. ':library) und you forgot to specify the subproject in the dependencies{} scriptblock of your :app module,
the manifest of :library and therefore the activities it declares, are not imported.
dependencies {
api project (':library')
You may check whether all activities show up in your app-debug.apk by using the following Android Studio menu command:
->Build->Analyze APK->app-debug.apk
Now open the AndroidManifest.xml and check its activity declarations.

I got this error in android 12+ after changing launch activity adding intent-filter but not make it exported.
so not forget.
android:exported="true"

It is likely that the action is not in the manifest.
This is the fix
Attached is an image

My main activity was not declared in Android Manifest File. That's the reason which came that error. This error come because of a declaration problem of Android Manifest file. Please check it. :D

This happened to me aswell took me ages to figure out why, but a weird bug I spotted is that if you run the app with breakpoints in your code without debugging mode it will cause this error to happen.
Quick fix for now: Only use breakpoints for degbugging mode.

Check your duplicate initialize activity in your AndroidManifest.xml
Like bellow:
<activity android:name=".nim.qiaqia.lota.LotaProduct"/>
<activity android:name=".nim.qiaqia.lota.LotaOrderDetail"/>
<activity android:name=".nim.qiaqia.main.activity.RechargeListLotaActivity"/>
<activity android:name=".nim.qiaqia.lota.MiningCoinLota"/>
<activity android:name=".nim.qiaqia.lota.LotaOrderDetail"/>
that can causes ""Default Activity not found" also. So, remove it and see. its works! :)

In my case android manifest was correct. I tried to invalidate Caches and restart but not worked. Then Rebuild project and it also did not work.
Then I realized that last night I added a new library to build Gradle, it was this:
implementation 'com.yalantis:eqwaves:1.0.1' And after removing this everything worked fine.
TIP: "Always have a track of things you do in your project, otherwise you will end up wasting your time"

If you only enabled building the app via app bundle, then this error might also occure when you try installing it as a default APK. Change the deployment option to APK from App Bundle and you are good to go.

How to add zxing in android studio?

When I add
dependencies {
compile 'com.google.zxing:core:3.0.0'
}
and
dependencies {
compile files('./libs/zxing/core.jar')
}
in build.gradle in both cases it shows error in manifest file
Cannot resolve symbol 'CaptureActivity'
Manifest File is as
<activity
android:name="com.google.zxing.client.android.CaptureActivity"
android:configChanges="orientation|keyboardHidden"
android:screenOrientation="landscape"
android:theme="#android:style/Theme.NoTitleBar.Fullscreen"
android:windowSoftInputMode="stateAlwaysHidden" >
<intent-filter>
<action android:name="com.google.zxing.client.android.SCAN" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
When i add
com.google.zxing.client.android.captureactivity.jar
in libs folder then Manifest error is solved but it gives
Multiple dex files define Lcom/google/zxing/BarcodeFormat;
Is it necessary to add captureactivity.jar in libs, if not then how to solve manifest error.

The short answer is: CaptureActivity is not part of the core library, and is not meant to be used as if it is a library. It is in android/, and you can reuse parts of that code for your own app, but you should be writing your own app from scratch rather than cloning the Barcode Scanner app, which seems to be your starting point here. Please read https://github.com/zxing/zxing/wiki/License-Questions

Migrating to Android Studio will cause multiple apps being installed for "single main project multiple library projects"

I have
Single main project which defines <action android:name="android.intent.action.MAIN" /> and <category android:name="android.intent.category.LAUNCHER" />
Multiple library projects, with some of them defines <action android:name="android.intent.action.MAIN" /> and <category android:name="android.intent.category.LAUNCHER" />
While I'm using Eclipse to build & run single main project with multiple library projects, only 1 app will be installed.
However, if I migrate to Android Studio to build & run single main project with multiple library projects, multiple apps will be installed,
depending on how many projects (regardless main project or library projects) define <action android:name="android.intent.action.MAIN" /> and <category android:name="android.intent.category.LAUNCHER" />
I was wondering, is there any configuration I had done wrong in Android Studio, which causes multiple app to be installed, when I build & run the projects?
Currently, my only workaround is to remove those lines (<action android:name="android.intent.action.MAIN" /> and <category android:name="android.intent.category.LAUNCHER" />) from all library projects' AndroidManifest.xml. Is that common & correct way, to import project libraries in Android Studio? As in Eclipse, those lines don't install extra apps into my device.
This is how my Project Structure looks like
As you can see the first folder icon, looks different than rest of the folder icons. I guess that indicate, the first folder icon is main project, the others are library projects.
If there is only 1 main project, how come there can be multiple apps being installed?

In Eclipse only the AndroidManifest.xml from main app project is used. In Android Studio (and Gradle build system) all the manifests are merged together.
The following lines inside an <activity> element in your manifest indicate that that activity should be shown in the launcher menu. If you do not wish this, remove those lines.
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
All of this is intended behavior.

There's another hackish way.
Look up at your merged AndroidManifest.xml. It should be located at:
<your_project>/build/intermediates/manifests/full/<debugOrRelease>/AndroidManifest.xml
Search for the LAUNCHER <activity> tag. In your case you should have more than 1 LAUNCHER <activity> tags. My case looks like this:
<activity
android:name="com.stockhut.SplashScreenActivity"
android:screenOrientation="portrait" >
<intent-filter>
<action android:name="android.intent.action.MAIN" >
</action>
<category android:name="android.intent.category.LAUNCHER" >
</category>
</intent-filter>
</activity>
...
<activity
android:name="com.todddavies.components.progressbar.main"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
In my case, com.todddavies.components.progressbar.main is a library project with a sample project that has been declared as LAUNCHER. The correct LAUNCHER should be com.stockhut.SplashScreenActivity.
Open AndroidManifest.xml in your main project, add the following:
<activity
android:name="com.todddavies.components.progressbar.main"
android:label="#string/app_name" tools:node="remove" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
Take note on the Marker tools:node="remove". According to Android Manifest Merger Documentation:
A marker is a special attribute, in the tools namespace, used to express a specific decision for how to resolve conflicts.
Therefore an <activity> tag with the marker tools:node="remove" will tell Gradle to remove itself when there's a conflict. In other words, we are somehow "forcing a conflict". It is a little hackish, but it works.
You can always verify your merged AndroidManifest.xml in the abovementioned path.

In Android studio their can be only one project at a time that can be added.
If you have library with project then you have to either add whole code inside you project or
you can create jar for your library project and add them into your project.
There is another option of gradle in Android studio.
If we want to use any library in project we can add their dependency in "build.gradle" file of Project.
I am attaching a screen shot of "build.gradle" file please refer to it.
Now , As far as Library Projects are concerned , (if it is not contributing to your project) The Best Approach is that in Android manifest you should set only your defined activity as a launcher activity ,As In Most cases libraries AndroidManifest.xml Often contain some sample Activity (which should be removed), or Activity which you need to subclass , There should be minimal defined things in the library project (negligible) most of the things should be in your Manifest including all permission.
Also it is define on android developer site
"a filter with "android.intent.action.MAIN" and
"android.intent.category.LAUNCHER" settings advertises an activity as
one that initiates an application — that is, as one that should be
displayed in the application launcher. The icon and label set in the
filter are therefore the ones displayed in the launcher."
you can refer the link also...
http://developer.android.com/guide/topics/manifest/manifest-intro.html

Default activity not created in Manifest file with Eclipse Juno

there maybe duplicate of this but I can't find any solution working for me.
I have downloaded latest Eclipse Juno from developer.android.com day before yesterday and it seems to act weirdly. I am trying to run "Hello World" but it is not creating default Activity in Manifest file.
Then I am also getting this error :
Unable to write Jarlist cache file
workspace\appcompat_v7\bin\jarlist.cacheworkspace\appcompat_v7\bin\jarlist.cache
Can someone please suggest

Add this code in your Manifest.
<activity
android:name=".MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>

No Launcher activity found, The launch will only sync the application package on the device

I got this warning from console when running my application on emulator
No Launcher activity found!
The launch will only sync the application package on the device!
In fact i have declared an activity as the main launcer in AndroidManifest.xml file
<activity
android:name=".myActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
I don't need any other intent-filter to use on that activity.. just basic main and launcher
What's the reason? Please give me a solution..

If the launcher activity is in another package, you will need to specify that as well.
For instance, from one of my personal projects:
<activity
android:name=".activities.MainScreen"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
The MainScreen.java is in the activities package. Also, check spelling for upper or lower case letters.

It seems that you must have "android.intent.action.MAIN" specified immediately before "android.intent.category.LAUNCHER". I encountered the same issue as you when I had the following:
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<action android:name="android.intent.action.SEARCH" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
The issue was resolved only when I re-orderd as follows:
<intent-filter>
<action android:name="android.intent.action.SEARCH" />
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>

In all normal circumstances, listen to what the other guy(s) said.
I was able to replicate your issue using a Mac Book Pro & Eclipse Indigo. when you create your android project, you MUST have Eclipse start you off with a templated activity (like a blank activity). if you don't, and you try to add an activity to your manifest later, Eclipse just derps and can't find the launcher. (i looked at other manifest files and i can't see any differences. i really don't think it's your poor manifest's fault in this special case.)
here's your lazy easy fix:
start a new project, and copy over all the files (make sure you back up ur files first, in case you delete something wrong or mess up the ordering)

Using Eclipse Indigo, open Run Configurations windows, click the project and use launch default activity on Android tab, choose Automatically pick compatible device...and apply.