Develop Reference

Why Android studio won't run app on Android Pie (9.0)?

I've upgraded my Google Pixel to Android 9.0/Pie.
When I try to run an application from Android studio I don't see the Google Pixel in the list, there's only a null device named FA69R0306649. When I run my application, Android studio tries to install the app but then fails.
It looks like Android Studio is not recognizing the phone anymore. It Worked perfectly fine a couple of hours ago under Oreo (8.x).
Also, if I deploy the app on google play as alpha and then download it runs perfectly under 9.0/Pie.
Any suggestions to get the run/debug working with android 9.0 phone under Android Studio (3.1.4)?

The Pixel running 9.0 requires USB 2.0 high speed.
Apparently the Pixel running Android Pie cannot talk to the PC using neither USB 3.0 nor USB 1.1 full speed nor USB 2.0 running at full speed.

I had a similar problem with my Xiaomi Mi A1. When I upgraded from Android 8.1 to 9 Android Studio would hang on "Installing application" forever.
After trying revoking USB debugging authorization and completely reenabling developer options with no success it turned out a simple restart did it.
Looks like there are multiple issues that lead to the same problem.

I had the same issue with a Xiaomi Mi A2 after upgrading to Android 9. If you are using Linux, try adding the udev permissions manually, following the steps described here. In my case, that was the only solution that worked.

Please re-enable developer options again after the OS version upgrade, the device name will appear and it will be working fine again

Install Sdk Platforms of Android 9. In Android studio Top Right besides Search Icon.Press That Icon of SDK manager and look either sdk platform is updated and installed.

A simple solution just go to your Developer option on your phone , right below the USB Debugging option it says to "install via USB" just enable it and you are all set to install an app through android studio into your 9.0 device.

Android Studio Not Deploying App

I currently have the latest version of Android Studio and I'm trying to deploy an app onto my phone running Android 5.0.1 Lollipop. After building, the terminal shows that the apk is being installed onto the phone and the status indicates that it is running. However, nothing shows up on my phone (no running applications and the app does not show up in the installed applications list). I've tried disabling auto-run in studio settings but it doesn't help. Any ideas why it's doing this? Also I reinstalled the adb driver just in case that was the cause. It might be helpful to note also that this happens even on the default template apps generated by studio.

try to turn off the Instant Run
File - Settings - Search Instant Run , unselect all the options
Hope this would help.

In my case the 'HMS Toolkit' (version 6.3.0.3003.AF) plugin, on Android Studio Chipmunk (version 2021.2.1), was causing this.
I've disabled it and it all started working again.

Xamarin.Android Projects failed to deploy in visual studio emulator for android

I'm using visual studio 2015 update 1 with windows 10 build 10586 TH1.
also I'm using Xamarin Version 4.0.1.96.
I have created a blank Xamarin.Forms app. It deploys to Windows Phone emulators without any issue. But unable to deploy to Android Emulators.
When I start android project Android Emulator launched successfully but visual studio freeze at this step.
I've tried a lot of android emulator profiles but cannot solve the problem.
This problem only exists for Emulators and project successfully deployed on physical android device.
I have the same issue with Xamarin.Android projects.
Here is all of the text in output window:
1>Starting deploy 4.5" KitKat (4.4) HDPI Phone ...
1>Starting emulator 4.5" KitKat (4.4) HDPI Phone ...
1>Validating emulator arguments...
1>Determining if emulator is already running...
1>Preparing virtual machine...
1>Launching emulator...
1>Emulator launched successfully
Thank you in advance for your help.

I was running into the same issue with the emulator starting up find but Visual Studio getting hung on the build/deploy. Finally figured it out from here.
Visual Studio gets stuck trying to deploy the app to the emulator or the emulator does not appear as a debug target in other IDEs
If the emulator is running, but it does not appear to be connected to
ADB (Android Debug Bridge) or it does not appear in Android tools that
make use of ADB (for example, Android Studio or Eclipse), you may need
to adjust where the emulator looks for ADB. The emulator uses a
registry key to identify the base location of your Android SDK, and
looks for the \platform-tools\adb.exe file under that directory. To
modify the Android SDK path used by the emulator:
Open Registry Editor by selecting Run from the Start buttons context menu, typing regedit in the dialog box, and choosing OK.
Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Android SDK Tools in the folder tree on the left.
Modify the Path registry variable to match the path to your Android SDK. Restart the emulator and you should now be able to see the
emulator connected to ADB and associated Android tools.
The value in my registry was set to "C:\Program Files (x86)\Android\android_sdk" (or similar). Updating it to "C:\Users\{USERNAME}\AppData\Local\Xamarin\MonoForAndroid\AndroidSDK" solved it for me. (I haven't yet worried about how to make this work for all users.)

I had the same issue but in my case it was not the registry. After doing a release build, I deployed the app to the emulator device in release mode which pushes the app to the device and then effectively "disconnects". These leaves a version of the app on the device which seems to block further attempts at debugging.
I solved it by starting the emulator, going to "settings -> apps" and manually uninstalling my app. Then the next debug build & deploy worked again.

I had the same issue. After a long struggle i fixed it.
Sol 1 :
Check with the registry as mentioned by others.
**HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Android SDK Tools**
Sol 2 :
In my case there is no android-SDK tool found in registry. So you have to add the registry manually here "**HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node**"
you can add it by right click on **Wow6432Node** => **New** => **key**.
Set Key name as **"Android SDK Tools"**then right click on **Android SDK Tools** =>**New** => **String Value**
Set Name as **Path** for newly added string. Then right click on **Path** => **Modify..**
Copy the Android SDK Tools path from program files and paste in Value Data.
Now the registry is created manually. You can debug the project via emulator.
Note : Don't forgot to restart the system.

Have a look here:
Xamarin Forms Android App Crashes Running Debug with VS Android Emulator
Start the Hyper-V manager
Select the emulator you are trying to use
Right-click, hit settings
Click processor
Click Compatibility
Set checkbox “Migrate to a physical computer with a different processor version”
You do not have this issue on a laptop because its processor does not provide the new features which are unsupported by the Android Emulator for Visual Studio. The described tweak is only needed on PCs with newer CPUs.

I got round this problem by starting Visual Studio as an administrator.

I too have had weirdness with the Visual Studio Emulator for Android and visual studio appearing to be stuck at the "Deploying ..." step trying to launch the app for debugging.
What I discovered is that restarting both the emulator and visual studio seems to make things better for me once it starts to do this.
Also, when debugging an app, it seems that exiting your app normally helps compared to when using the "Stop Debugging" button.
For example, I started my app twice and killed it w/ the "Stop Debugging" button, but couldn't deploy/start the app a 3rd time w/out a restart of visual studio and the emulator.
Am using VS 2015 Community edition w/ update 3.

I just had a very interesting experience,
In my case the registry path to SDK was correct,
I had unchecked the "Use Fast Deployment" (under packaging properties in android options), and
all my efforts to reboot the PC, close VS, Close Emulator start over had failed.
However I did these two:
1 - Updated all the components in android SDK manager and restarted the PC,
2 - Disabled my anti-virus! and then suddenly VS deployed the app to the emulator!! (It was stuck in the same situation where the emulator starts and nothing happens!, I did this out of despair!)
(OS: win 7, professional, VS 2017 Community edition!)
More Details
I have been trying this for three more days
For my special case disabling the Anti Virus seems to solve the issue every single time!

The solution for me was to Check the deploy box in the Configuration Manager
This answer came from Xamarin Forum

Visual Studio 2015 missing android emulator

After installing Visual Studio 2015 Preview, I've checked android emulator when second installer prompt, but when I create a new android project, there are no android emulator option with X86, only a start button is exist...
Can anyone please help me to solve this issue?

Update as per comment below: You need Hyper-V enabled on your machine to run the VS Emulator for Android.
Sorry, I cannot tell from your blurry screenshot if this is a C++ or a Cordova or a Xamarin project in VS2015. In any case can you try with the other project type to see if this is a project type issue or an emulator issue?
Also I presume you have all the requirements such as Hyper-V enabled, correct? You can read more about the VS Emulator for Android and its requirements here:
http://blogs.msdn.com/b/visualstudioalm/archive/2014/11/12/introducing-visual-studio-s-emulator-for-android.aspx

Visual Studio Android Emulator won't run application

I recently got into Xamarin development. I have a lot of experience in Xcode making iOS apps and the iOS side was very straight forward. Now I'm trying to implement Android. I downloaded a Hello World example to get my bearings. When I run it I have no problems getting the simulator to show up (MonoForAndroid_API_10 and MonoForAndroid_API_12) but the actual application doesn't run, and does not show up anywhere on the simulator. Essentially whenever I use run or run with in Xamarin on Android, it pulls up a fully functioning, albeit empty simulator.
How do I get my application to run on the emulator?

Like the other commenters, this is most likely just a symptom of slow emulator on your machine. I'm running Xamarin-Android development on my 2010-era OSX machine in mavericks with 8GB RAM, and it is slow-slow-slow, but usable. Try to find the Intel x86 speeds improvements (look for HAXM) and you will find that the emulator will be much much faster.
And yeah, get a real handset and plug it in to your computer: always much faster than emulation.
later edit Get Genymotion for Mac OSX or for PC/Windows or PC/Linux. It's way way way faster than the other emulators. I have since found that this is as fast, or faster, than running the App on my connected Android phone. It's certainly simpler in not having to have the device plugged into one of my USB ports, and allows me to code and test on the train. http://www.genymotion.com/

Don't know if my issue was the same but finally this troubleshooting helped me to run emulator https://msdn.microsoft.com/en-us/library/mt228282.aspx#ADB.
I was missing key Android SDK Tools with string value Path in registry Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node
I've created it manually and it worked.
UPDATE
Before I got the issue with running emulator, I couldn't see it in Visual Studio. The reason was I've installed VS Android Emulator through standalone installation, not through VS Installer. It had to be installed there as well.

I had the similar issue, and then I deleted the existing device simulator and reinstalled again and it started working.

As I use a different SDK, in my case
Go to Tools > Options > Xamarin and set the Android SDK path.
Sometime Visual Studio changes this configuration;

2020 Update:
I followed the most voted comment, however, with Visual Studio 2019 updated recently, the steps have changed a little. Here is what previously worked:
WHAT WORKED BEFORE
"Don't know if my issue was the same but finally this troubleshooting helped me to run emulator https://msdn.microsoft.com/en-us/library/mt228282.aspx#ADB. I was missing key Android SDK Tools with string value Path in registry Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node
I've created it manually and it worked."
WHAT TO DO INSTEAD
Nothing. Don't mess with the path.
WHAT WORKED BEFORE
"Before I got the issue with running emulator, I couldn't see it in Visual Studio. The reason was I've installed VS Android Emulator through standalone installation, not through VS Installer. It had to be installed there as well."
Previous instructions image
WHAT TO DO INSTEAD
a. Go to Tools located at the top of the VS window, Get Tools and Features, go to Individual components, using the search tool in the pop up box, search "emulator", once you get the result, make sure both Google Android Emulator (API Level 25)(local install) and Intel Hardware Accelerated Execution Manager (HAXM) (local install) are both checked.
b. Close the solution(s) and restart VS then reopen the solution(s).
c. To deploy the app on the emulator, click Start button to spin up the emulator, left click on your Android project, then click Deploy. You should be able to see your app on your emulator's app menu.
Updated Instructions image

Worked for ME
Sometimes you close the android Emulator but not POWEROFF the Emulator.
this problem happens when emulator shutdown un-properly.
Restart Your EMULATOR
First start your emulator
Then restart your emulator by pressing down the power button and select restart option in your android emulator.

I enabled Hyper-V acceleration based on microsoft documentations: https://learn.microsoft.com/en-us/xamarin/android/get-started/installation/android-emulator/hardware-acceleration?tabs=vswin&pivots=windows#accelerating-with-hyper-v
Basically you need to turn on these two windows features from the control panel (Turn windows features on of off):
Hyper-V.
Windows hypervisor platform.
then from visual studio go to: Tools >> Android >> Android SDK manager >> Tools >> make sure that "Android emulator" version is 27.0.1 or higher, if not, you will find in the same screen a button below to update it.
I did this on windows 10 64-bit, with VS 2017 Community 15.9.5