Develop Reference

App only running on devices that were connected to laptop

I have a problem with my app release.
If I have the phone connected to my laptop it asks if I want to share the RSA fingerprint like this:
After I click yes, I can run the build and install the app on the phone successfully. I can even build an APK, debug or release and install it on any phone that was connected to my PC and accepted the RSA key(4 devices).
When I try to install that APK on another phone(tested on 3 other devices). It installs the debug APK but just says my app has stopped working and if I install the release APK , it just simply doesn't install.
Is this a common issue, is there something I need to do first?

You should allow the debugging option for your actual device. and always check the "Always allow this computer" and click okay.
UPDATE
Solution 1: uninstall the application in the device and try to install it again
Solution 2: go build>Build APK> and copy the apk file. And distribute it to others.
Solution 3: try to generated signed apk.Check the signature both version.

I would advise you to build a signed apk before sharing. Instructions on how to sign your apk can be found here -> https://developer.android.com/studio/publish/app-signing

Nearby Messages API not working after release

I´ve got a problem with the Nearby Messages API. Following scenario:
When I test my App with Android Studio everything is working fine, Messages are sent and get received.
When I build an APK and install the generated (and signed) APK on the phone, Nearby Messages doesn´t work anymore. It won´t find any messages...
Does anyone had a similar problem or knows a solution (better knows the reason WHY it´s not working)?
UDPATE

In the side bar of Android bar , you will have the tab "build variants" , change the option from debug to release and then run the signing report , you will get the release sha -1 key.

When you sign apk for release with a Keystore, the SHA-1 fingerprint will be different than the debug version. This prevents the Google apis from working.
Use this in CMD to find out SHA-1 of release apk
keytool -list -v -keystore mystore.keystore

Google map Not Working in Released .apk?

I have use, fragment for maps. and also i have putted same API key in both debug and release google_maps_api.xml
but it works only on debug mode. in release mode maps fragment is shown as empty. how to fix this issue.

referring to https://developers.google.com/maps/documentation/android-api/signup
you will have 2 SHA keys ... one for debug, one for release.
just enter the SHA finger print for the release app into your console and it should work.
open your console using this link https://console.developers.google.com/flows/enableapi?apiid=maps_android_backend&reusekey=true
under credentials, enter the sha and your package names (see image below).
For my case, i use the same API key for two apps (and debug and release), hence there are 4 rows.

Pls. try this:
use adb to install the apk on your device/emulator (adb install app.apk). Don't forget to uninstall the debug version first, otherwise the signature difference will prevent the installation

Android: Error - App has same packaged different signature

I am getting an issue where android studio is saying
Installation failed since the device has an application with the same package but a different signature. . . ..
This is correct, as I recently signed an APK and uploaded to the beta area of my play developer console.
And now I am trying to debug it locally and by default I believe that all Android projects are signed by the debug keystore hence the signatures would be different.
What is the best way to deal with this? Would it be possible to sign my debug version with my release key, and is there a potential danger here?
How would I force the signing of my debug version with my release keystore without losing the ability to debug, etc.?
Or should I just keep uninstalling and reinstalling the different versions - that seems the worst possible workaround. :-)

You can sign your apps with your release key while keeping the debugging option - you just have to add your release key into Android Studio (or specify it on the command line if you are signing your apps there).
In Android Studio, right click on your app in the project browser and open module settings. Select your app's module and click on 'Signing' to make sure your release keystore is listed. Then under 'Build Types', make sure that the debug target and the release target share the same signing config, and that the debug target has debuggable set to true. They should now share the same key.
More information on app signing can be found in the Developer docs here.
I haven't heard of a downside to using the same key for debugging and for release, provided the private key is kept secure (read: not under version control).

In my case after upgrading Android Studio, I had removed the $HOME/.android folder which made Android Studio create a new $HOME/.android/debug.keystore.
After copying the old debug.keystore it worked again.

try change debug to release in builds variants

In my case, the problem was fixed by adding the SHA-1 and SHA-256 certificate fingerprints given in Android Studio (click on Gradle on the right side of the AS window, then run configurations and signingReport) to your Firebase project settings->General->SDK setup and configuration.
By the way, this also solved the problem I was getting logging in and getting the cryptic error Activity.RESULT_CANCELED.

changing the app id in gradle files did it for me
defaultConfig {
applicationId 'com.example.app'
}

Why I cannot attach debugger to signed apk process?

I made a signed APK and installed it on the device (Galaxy S5). The run the app and tried to attach to it from IntelliJ IDEA 13.1. But IDEA cannot see any process on my device
You can see that part belonging to the device is empty.
If I install the debug version of the app, then I can attack the debugger to it. But not if it's been created as a signed APK.
Where am I making a mistake? Why I cannot debug signed APK?

Have you set android:debuggable="true" in the application tag of your manifest file? Also, take a look at How to debug apk signed for release?

In Android Studio stable, you have to add the following 2 lines to application in the AndroidManifest file:
android:debuggable="true"
tools:ignore="HardcodedDebugMode"
The first one will enable debugging of signed APK, and the second one will prevent compile-time error.
After this, you can attach to the process via "Attach debugger to Android process" button.

If the app is signed and installed over the Google play store, attaching to a process is not allowed. Currently the Google play store rejects the upload of any apk with:
android:debuggable="true"