Develop Reference

I can not see hello world app in Android Studio

Hi I have installed Android studio correctly. I made AVD for e.q Marshmallow and project on the same platform. after press RUN, AVD turns on. I can do everything on emulated android phone(other issue- after running this my computer dramticly slowing down) but I should see my "Hello world" app, there is not there. I'm getting following error
Unexpected error while executing: am start -n "com.example.zad2/com.example.zad2.MainActivity" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Error while Launching activity
where zad2 is my project name.
On Stacfoverflow i saw tips to add into manifest some filter code but I already have it:
<?xml version="1.0" encoding="utf-8"?>
<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/Theme.Zad2">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>

Yea don't trouble friends. I found this post: Session 'app': Error Launching activity
and I unistalled my app from AVD :)

Android Studio launches wrong Activity when merging AndroidManifest from ProductFlavorBuildType hybrid directory

I'm using Android Studio 2.1.3 (Mac OS X) and com.android.tools.build:gradle:2.1.3. I've already tried invalidating cache and restarting and clean builds.
I have a project with many ProductFlavors, all of which use the same starting activity save one (this one is a paid version that uses the licensing library, all the others are free so I don't bother, although a solution might just be to use the licensed version of the activity for all flavors but skip the licensing unless a resource is set... just seems too easy to hack). I thus have 2 AndroidManifest.xml files:
// app/src/main/AndroidManifest.xml
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.company.app">
...
<application android:allowBackup="true" android:icon="#mipmap/ic_launcher"
android:label="#string/appFriendlyName"
android:theme="#style/AppTheme">
<activity
android:name="com.company.app.TabsFragmentActivity"
android:screenOrientation="portrait"
android:label="#string/appFriendlyName">
<intent-filter android:label="#string/launcherLabel">
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
...
</application>
</manifest>
// app/src/PaidFlavor/AndroidManifest.xml
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com.company.app">
<application android:allowBackup="true" android:icon="#mipmap/ic_launcher"
android:label="#string/appFriendlyName"
android:theme="#style/AppTheme">
<activity
tools:node="merge"
android:name="com.company.app.TabsFragmentActivityLicensed"
android:screenOrientation="portrait"
android:label="#string/appFriendlyName">
<intent-filter android:label="#string/launcherLabel">
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
tools:node="remove"
android:name="com.company.app.TabsFragmentActivity"/>
</application>
</manifest>
This works great, and I can inspect the generated intermediate (merged) AndroidManifest.xml, and indeed the TabsFragmentActivity activity is removed, and the TabsFragmentActivityLicensed is added, and all is right with the world.
But I don't want the debug version (build type) to be licensed. Again, I can work around it easy enough in code, but it's the principle of the matter! So I thought it would be easy to just move
app/src/PaidFlavor/AndroidManifest.xml
to
app/src/PaidFlavorRelease/AndroidManifest.xml
This is where things go wrong. Everything builds without error, and I look at the intermediate (merged) manifest and it still looks correct. However, Android Studio tries to launch the PaidFlavor with release build type as:
adb shell am start -n "com.company.project/com.company.app.TabsFragmentActivity" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Wrong activity! Where's it getting it from? Am I using the wrong subdirectory (PaidFlavorRelease/)? This results in the obvious error:
Error while executing: am start -n "com.company.project/com.company.app.TabsFragmentActivity" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Starting: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] cmp=com.company.project/com.company.app.TabsFragmentActivity }
Error type 3
Error: Activity class {com.company.project/com.company.app.TabsFragmentActivity} does not exist.
Error while Launching activity

Launcher Activity Issue Android

I created a splash screen for my android application. In my AndroidManifest I set the SplashScreen Activity as Launcher and action as MAIN. After that I changed the HomeActivity's intentfilter.
Here is my android manifest file:
<application
android:allowBackup="true"
android:icon="#mipmap/icon"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".SplashScreenActivity"
android:screenOrientation="portrait">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".ActivityHome"
android:screenOrientation="portrait">
<intent-filter>
<action android:name="android.intent.action.ACTIVITHOME" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<receiver android:name=".Receivers.NetworkReceiver"></receiver>
</application>
I have both these activities inside the default package. Now, when I try to test the application in device, I get the following error:
Error while executing: am start -n "com.sdz.myapp/com.sdz.myapp.SplashScreenActivity" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Starting: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] cmp=com.sdz.myapp/.SplashScreenActivity }
Error type 3
Error: Activity class {com.sdz.myapp/com.sdz.myapp.SplashScreenActivity} does not exist.
Error while Launching activity
This is how my project structure looks like:
src
-com.sdz.myapp
----ActivityHome
----SplashScreenActivity
I restarted android studio but still the error is there. I dont know what is causing this.

I ran into this as well. I actually had to uninstall the apk from the device before it would work... which was really odd as the app wasn't showing up on my list of apps on the phone.
Here's what I did:
Opened up command line
Ran 'adb devices' to make sure my device was connected
ran 'adb uninstall ' Replace with "com.whatever.blah"
You should see a message saying it uninstall successfully
Try installing from Android Studio again and it should work
I have no idea how it gets in this weird state. :-/

Please change your android:name value at your activity tag with full name and first clean project . After that try to run your application again
<activity android:name="com.sdz.myapp.SplashScreenActivity"
android:screenOrientation="portrait">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>

I have this same issue occasionally. The solution was to build the APK (menu "Build > Build APK") and install it manually in the phone. After that the error disappears.

I tried all of the above plus even delete the build folder and still did not work. The solution for me was: On your Android Studio go to File->Sync Project with Gradle Files

app install on device/emulator but not starts automatically

I have installed a new setup of adb-bundle. When I run the project apk installed on device/emulator but not opens automatically. This problem is not related to coding I this it is related to eclipse setup because it happens with all projects. Please Help. Facing issue with debugging due to this problem.
Manifest.xml:
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.demo.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>
</application>
Thanks

It seems like you have a problem with the adb. Open task manager and kill the adb process and restart everything and try again. If you have made some changes to the installed adb try to install it again properly.
Check the below links also,
https://lesleyharrison.wordpress.com/2011/01/15/solution-for-android-emulator-starts-but-app-doesnt-run/
Android application doesn't start from Eclipse

AVD is up and running but eclipse doesnt detects

My AVD is running properly and in the process tab, there's an emulator-arm.exe so i'm pretty sure about it but when i run my program with a run configuration that says to pick up this AVD, i get the following message.
Android Launch!
[2015-02-15 00:38:50 - FirstApp] adb is running normally.
[2015-02-15 00:38:50 - FirstApp] Performing com.protyay.example.firstapp.Splash activity launch
[2015-02-15 00:38:50 - FirstApp] No active compatible AVD's or devices found. Relaunch this configuration after connecting a device or starting an AVD.
This is the Manifest.xml looks like, and as a matter of fact, i have had absolutely no problems testing this app until yesterday. A strange problem
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="com.protyay.example.firstapp.MAINACTIVITY" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
<activity
android:name=".Splash"
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>
API level for AVD is 19

Try to this, It may be a helpful
Go To Window->Show View->Others->Device->Reset Adb

Reset your ADB process. You can do that within the DDMS Perspective (then the Devices window). T he last menu on the right (the upside down triangle - on the main 'devices' panel - the one that 'should' show your device in the list) has this option in there - it is named 'Reset ADB'.
Also, you can do this following from the command-line:
1. adb kill-server
2. adb start-server