Accelerating with Hyper-V

Your computer must be updated to Windows 10 April 2018 update (build 1803) or later. You can verify that your Windows version is up-to-date by using the following steps:

1. Enter About in the Windows search box.

2. Select About your PC in the search results.

3. Scroll down in the About dialog to the Windows specifications section.

4. Verify that the Version is at least 1803:

1. Enter windows features in the Windows search box and select Turn Windows features on or off in the search results. In the Windows Features dialog, enable both Hyper-V and Windows Hypervisor Platform :

After making these changes, reboot your computer.

Android Device Manager on Windows

How to use the Android Device Manager to create, duplicate, customize, and launch Android virtual devices.

Clicking New launches the New Device screen:

This article explains how to use the Android Device Manager to edit the profile properties of an Android virtual device.

Android Device Manager on Windows

The Android Device Manager supports the editing of individual Android virtual device profile properties. The New Device and Device Edit screens list the properties of the virtual device in the first column, with the corresponding values of each property in the second column (as seen in this example):

Deployment issues on Windows

Some error messages may be displayed by the emulator when you deploy your app. The most common errors and solutions are explained here.

Deployment errors

If you see an error about a failure to install the APK on the emulator or a failure to run the Android Debug Bridge (adb), verify that the Android SDK can connect to your emulator. To verify emulator connectivity, use the following steps:

1. Launch the emulator from the Android Device Manager (select your virtual device and click Star t).

2. Open a command prompt and go to the folder where adb is installed. If the Android SDK is installed at its default location, adb is located at C:\Program Files (x86)\Android\android-sdk\platform-

tools\adb.exe; if not, modify this path for the location of the Android SDK on your computer.

3. Type the following command:

4. If the emulator is accessible from the Android SDK, the emulator should appear in the list of attached devices. For example:

5. If the emulator does not appear in this list, start the Android SDK Manager , apply all updates, then try launching the emulator again.

MMIO access error

If the message An MMIO access error has occurred is displayed, restart the emulator.

Missing Google Play Services

If the virtual device you are running in the emulator does not have Google Play Services or Google Play Store installed, this condition is often caused by creating a virtual device without including these packages. When you create a virtual device (see Managing Virtual Devices with the Android Device Manager), be sure to select one or both of the following options:

Google APIs – includes Google Play Services in the virtual device. Google Play Store – includes Google Play Store in the virtual device.

For example, this virtual device will include Google Play Services and Google Play Store:

Performance issues

Performance issues are typically caused by one of the following problems: The emulator is running without hardware acceleration.

The virtual device running in the emulator is not using an x86-based system image.

The following sections cover these scenarios in more detail.

Hardware acceleration is not enabled

If hardware acceleration is not enabled, starting a virtual device from the Device Manager will produce a dialog with an error message indicating that the Windows Hypervisor Platform (WHPX) is not configured properly:

If this error message is displayed, see Hardware acceleration issues below for steps you can take to verify and enable hardware acceleration.

Acceleration is enabled but the emulator runs too slowly

A common cause for this problem is not using an x86-based image in your virtual device (AVD). When you create a virtual device (see Managing Virtual Devices with the Android Device Manager), be sure to select an x86-based system image:

Hardware acceleration issues

Whether you are using Hyper-V or HAXM for hardware acceleration, you may run into configuration problems or conflicts with other software on your computer. You can verify that hardware acceleration is enabled (and which acceleration method the emulator is using) by opening a command prompt and entering the following command:

This command assumes that the Android SDK is installed at the default location of C:\Program Files

(x86)\Android\android-sdk; if not, modify the above path for the location of the Android SDK on your computer.

Hardware acceleration not available

If Hyper-V is available, a message like the following example will be returned from the emulator-check.exe accel command:

If HAXM is available, a message like the following example will be returned:

If hardware acceleration is not available, a message like the following example will be displayed (the emulator looks for HAXM if it is unable to find Hyper-V):

If hardware acceleration is not available, see Accelerating with Hyper-V to learn how to enable hardware acceleration on your computer.

Incorrect BIOS settings

If the BIOS has not been configured properly to support hardware acceleration, a message similar to the following example will be displayed when you run the emulator-check.exe accel command:

To correct this problem, reboot into your computer's BIOS and enable the following options:

Virtualization Technology (may have a different label depending on motherboard manufacturer). Hardware Enforced Data Execution Prevention.

If hardware acceleration is enabled and the BIOS is configured properly, the emulator should run successfully with hardware acceleration. However, problems may still result due to issues that are specific to Hyper-V and HAXM, as explained next.

Hyper-V issues

In some cases, enabling both Hyper-V and Windows Hypervisor Platform in the Turn Windows features on or off dialog may not properly enable Hyper-V. To verify that Hyper-V is enabled, use the following steps:

1. Enter powershell in the Windows search box.

2. Right-click Windows PowerShell in the search results and select Run as administrator .

3. In the PowerShell console, enter the following command:

If Hyper-V is not enabled, a message similar to the following example will be displayed to indicate that the state of Hyper-V is Disabled:

4. In the PowerShell console, enter the following command:

If the Hypervisor is not enabled, a message similar to the following example will be displayed to indicate that the state of HypervisorPlatform is Disabled:

If Hyper-V and/or HypervisorPlatform are not enabled, use the following PowerShell commands to enable them:

After these commands complete, reboot.

For more information about enabling Hyper-V (including techniques for enabling Hyper-V using the Deployment Image Servicing and Management tool), see Install Hyper-V.

HAXM issues

HAXM issues are often the result of conflicts with other virtualization technologies, incorrect settings, or an out- of-date HAXM driver.

HAXM process is not running

If HAXM is installed, you can verify that the HAXM process is running by opening a command prompt and entering the following command:

If the HAXM process is running, you should see output similar to the following result:

STATE

If problem.

is not set to

, see How to Use the Intel Hardware Accelerated Execution Manager to resolve the

RUNNING

HAXM virtualization conflicts

HAXM can conflict with other technologies that use virtualization, such as Hyper-V, Windows Device Guard, and some antivirus software:

Hyper-V – If you are using a version of Windows before the Windows 10 April 2018 update (build 1803) and Hyper-V is enabled, follow the steps in Disabling Hyper-V so that HAXM can be enabled.

Device Guard – Device Guard and Credential Guard can prevent Hyper-V from being disabled on Windows machines. To disable Device Guard and Credential Guard, see Disabling Device Guard.

Antivirus Software – If you are running antivirus software that uses hardware-assisted virtualization (such as Avast), disable or uninstall this software, reboot, and retry the Android emulator.

Incorrect BIOS settings

If you are using HAXM on a Windows PC, HAXM will not work unless virtualization technology (Intel VT-x) is enabled in the BIOS. If VT-x is disabled, you will get an error similar to the following when you attempt to start the Android Emulator:

This computer meets the requirements for HAXM, but Intel Vir tualization Technology (VT-x) is not turned on.

To correct this error, boot the computer into the BIOS, enable both VT-x and SLAT (Second-Level Address Translation), then restart the computer back into Windows.

Disabling Hyper-V

If you are using a version of Windows before the Windows 10 April 2018 Update (build 1803) and Hyper- V is enabled, you must disable Hyper-V and reboot your computer to install and use HAXM. If you are using

Windows 10 April 2018 Update (build 1803) or later, Android Emulator version 27.2.7 or later can use Hyper-V (instead of HAXM) for hardware acceleration, so it is not necessary to disable Hyper-V.

You can disable Hyper-V from the Control Panel by following these steps:

1. Enter windows features in the Windows search box and select Turn Windows features on or off in the search results.

2. Uncheck Hyper-V:

3. Restart the computer.

Alternately, you can use the following PowerShell command to disable the Hyper-V Hypervisor:

Intel HAXM and Microsoft Hyper-V cannot both be active at the same time. Unfortunately, there is no way to switch between Hyper-V and HAXM without restarting your computer.

In some cases, using the above steps will not succeed in disabling Hyper-V if Device Guard and Credential Guard are enabled. If you are unable to disable Hyper-V (or it seems to be disabled but HAXM installation still fails), use the steps in the next section to disable Device Guard and Credential Guard.

Disabling Device Guard

Device Guard and Credential Guard can prevent Hyper-V from being disabled on Windows machines. This situation is often a problem for domain-joined machines that are configured and controlled by an owning organization. On Windows 10, use the following steps to see if Device Guard is running:

1. Enter System info in the Windows search box and select System Information in the search results.

2. In the System Summary , look to see if Device Guard Vir tualization based security is present and is in the Running state:

If Device Guard is enabled, use the following steps to disable it:

1. Ensure that Hyper-V is disabled (under Turn Windows Features on or off) as described in the previous section.

2. In the Windows Search Box, enter gpedit.msc and select the Edit group policy search result. These steps launch the Local Group Policy Editor .

3. In the Local Group Policy Editor , navigate to Computer Configuration > Administrative Templates > System > Device Guard:

4. Change Turn On Vir tualization Based Security to Disabled (as shown above) and exit the Local Group Policy Editor .

5. In the Windows Search Box, enter cmd. When Command Prompt appears in the search results, right- click Command Prompt and select Run as Administrator .

6. Copy and paste the following commands into the command prompt window (if drive Z: is in use, pick an unused drive letter to use instead):

7. Restart your computer. On the boot screen, you should see a prompt similar to the following message: Do you want to disable Credential Guard?

Press the indicated key to disable Credential Guard as prompted.

8. After the computer reboots, check again to ensure that Hyper-V is disabled (as described in the previous steps).

If Hyper-V is still not disabled, the policies of your domain-joined computer may prevent you from disabling Device Guard or Credential Guard. In this case, you can request an exemption from your domain administrator to allow you to opt out of Credential Guard. Alternately, you can use a computer that is not domain-joined if you must use HAXM.

Additional troubleshooting tips

The following suggestions are often helpful in diagnosing Android emulator issues.

Starting the emulator from the command line

If the emulator is not already running, you can start it from the command line (rather than from within Visual Studio) to view its output. Typically, Android emulator AVD images are stored at the following location (replace username with your Windows user name):

C:\Users\username\.android\avd

You can launch the emulator with an AVD image from this location by passing in the folder name of the AVD. For example, this command launches an AVD named Pixel_API_27 :

This example assumes that the Android SDK is installed at the default location of C:\Program Files

(x86)\Android\android-sdk; if not, modify the above path for the location of the Android SDK on your computer.

When you run this command, it will produce many lines of output while the emulator starts up. In particular, lines such as the following example will be printed if hardware acceleration is enabled and working properly (in this example, HAXM is used for hardware acceleration):

Viewing Device Manager logs

Often you can diagnose emulator problems by viewing the Device Manager logs. These logs are written to the following location:

C:\Users\username\AppData\Local\Xamarin\Logs\16.0

You can view each DeviceManager.log file by using a text editor such as Notepad. The following example log entry indicates that HAXM was not found on the computer:

MMIO access error

If An MMIO access error has occurred is displayed, restart the emulator.

Missing Google Play Services

If the virtual device you are running in the emulator does not have Google Play Services or Google Play Store installed, this condition is usually caused by creating a virtual device without including these packages. When you create a virtual device (see Managing Virtual Devices with the Android Device Manager), be sure to select one or both of the following:

Google APIs – includes Google Play Services in the virtual device. Google Play Store – includes Google Play Store in the virtual device.

For example, this virtual device will include Google Play Services and Google Play Store:

Performance issues

Performance issues are typically caused by one of the following problems: The emulator is running without hardware acceleration.

The virtual device running in the emulator is not using an x86-based system image.

The following sections cover these scenarios in more detail.

Hardware acceleration is not enabled

If hardware acceleration is not enabled, a dialog may pop up with a message such as device will run unaccelerated when you deploy your app to the Android emulator. If you are not certain whether hardware acceleration is enabled on your computer (or you would like to know which technology is providing the acceleration), see Hardware acceleration issues below for steps you can take to verify and enable hardware acceleration.

Acceleration is enabled but the emulator runs too slowly

A common cause for this problem is not using an x86-based image in your virtual device. When you create

virtual device (see Managing Virtual Devices with the Android Device Manager), be sure to select an x86-based system image:

Hardware acceleration issues

Whether you are using the Hypervisor Framework or HAXM for hardware acceleration of the emulator, you may run into problems caused by installation issues or an out-of-date version of macOS. The following sections can help you resolve this issue.

Hypervisor Framework issues

If you are using macOS 10.10 or later on a newer Mac, the Android emulator will automatically use the Hypervisor Framework for hardware acceleration. However, some older Macs or Macs running a version of macOS earlier than 10.10 may not provide Hypervisor Framework support.

To determine whether or not your Mac supports the Hypervisor Framework, open a Terminal and enter the following command:

If your Mac supports the Hypervisor Framework, the above command will return the following result:

If the Hypervisor Framework is not available on your Mac, you can follow the steps in Accelerating with HAXM to use HAXM for acceleration instead.

HAXM issues

If the Android Emulator does not start properly, this problem is often caused by problems with HAXM. HAXM issues are often the result of conflicts with other virtualization technologies, incorrect settings, or an out-of-date HAXM driver. Try reinstalling the HAXM driver, using the steps detailed in Installing HAXM.

Additional troubleshooting tips

The following suggestions are often helpful in diagnosing Android emulator issues.

Starting the emulator from the command line

If the emulator is not already running, you can start it from the command line (rather than from within Visual Studio for Mac) to view its output. Typically, Android emulator AVD images are stored at the following location:

~/.android/avd

You can launch the emulator with an AVD image from this location by passing in the folder name of the AVD. For example, this command launches an AVD named Pixel_2_API_28 :

If the Android SDK is installed at its default location, the emulator is located in the

~/Librar y/Developer/Xamarin/android-sdk-macosx/emulator directory; if not, modify this path for the location of the Android SDK on your Mac.

When you run this command, it will produce many lines of output while the emulator starts up. In particular, lines such as the following example will be printed if hardware acceleration is enabled and working properly (in this example, Hypervisor Framework is used for hardware acceleration):

Viewing Device Manager logs

Often you can diagnose emulator problems by viewing the Device Manager logs. These logs are written to the following location:

~/Librar y/Logs/XamarinDeviceManager

You can view each Android Devices.log file by double-clicking it to open it in the Console app. The following example log entry indicates that HAXM was not found:

How to setup an Android device and connect it to a computer so that the device may be used to run and debug Xamarin.Android applications.

After testing on an Android emulator, you will want to see and test your apps running on an Android device. You will need to enable debugging and connect the device to the computer.

Each of these steps will be covered in more detail in the sections below.

Enable Debugging on the Device

A device must be enabled for debugging in order to test an Android application. Developer options on Android have been hidden by default since version 4.2, and enabling them can vary based on the Android version.

Android 9.0+

For Android 9.0 and higher, debugging is enabled by following these steps:

1. Go to the Settings screen.

2. Select About Phone .

3. Tap Build Number 7 times until You are now a developer! is visible.

Android 8.0 and Android 8.1

1. Go to the Settings screen.

2. Select System .

3. Select About Phone

4. Tap Build Number 7 times until You are now a developer! is visible.

Android 7.1 and lower

1. Go to the Settings screen.

2. Select About Phone.

3. Tap Build Number 7 times until You are now a developer! is visible.

Verify that USB debugging is enabled

After enabling developer mode on your device, you must ensure that USB debugging is enabled on the device. This also varies based on the Android version.

Android 9.0+

Navigate to Settings > System > Advanced > Developer Options and enable USB Debugging.

Android 8.0 and Android 8.1

Navigate to Settings > System > Developer Options and enable USB Debugging.

Android 7.1 and lower

Navigate to Settings > Developer Options and enable USB Debugging.

Once the Developer Options tab is available under Settings > System , open it to reveal developer settings:

This is the place to enable developer options such as USB debugging and stay awake mode.

Connect the device to the computer

The final step is to connect the device to the computer. The easiest and most reliable way is to do so over USB.

You will receive a prompt to trust the computer on your device if you have not used it for debugging before. You can also check Always allow from this computer to prevent requiring this prompt each time you connect the device.

Alternate connection via Wifi

It is possible to connect an Android device to a computer without using a USB cable, over WiFi. This technique requires more effort but could be useful when the device is too far from the computer to remain constantly plugged-in via cable.

Connecting over WiFi

By default, the Android Debug Bridge (ADB) is configured to communicate with an Android device via USB. It is possible to reconfigure it to use TCP/IP instead of USB. To do this, both the device and the computer must be on the same WiFi network. To setup your environment to debug over WiFi complete the following steps from the command line:

1. Determine the IP address of your Android device. One way to find out the IP address is to look under

Settings > Network & internet > Wi-Fi, then tap on the WiFi network that the device is connected to, and then tap on Advanced. This will open a dropdown showing information about the network connection, similar to what is seen in the screenshot below:

On some versions of Android the IP address won't be listed there but can be found instead under Settings > About phone > Status .

2. Connect your Android device to your computer via USB.

3. Next, restart ADB so that it using TCP on port 5555. From a command prompt, type the following command:

After this command is issued, your computer will not be able to listen to devices that are connected via USB.

4. Disconnect the USB cable connecting your device to your computer.

5. Configure ADB so that it will connect to your Android device on the port that was specified in step 1 above:

Once this command finishes the Android device is connected to the computer via WiFi.

When you're finished debugging via WiFi, it's possible to reset ADB back to USB mode with the following command:

It's possible to request ADB to list the devices that are connected to the computer. Regardless of how the devices are connected, you can issue the following command at the command prompt to see what is connected:

Troubleshooting

In some cases you might find that your device cannot connect to the computer. In this case you may want to verify that USB drivers are installed.

Install USB Drivers

This step is not necessary for macOS; just connect the device to the Mac with a USB cable.

It may be necessary to install some extra drivers before a Windows computer will recognize an Android device connected by USB.

Run the android.bat application in the [Android SDK install path]\tools directory. By default, the Xamarin.Android installer will put the Android SDK in following location on a Windows computer:

Download the USB Drivers

Google Nexus devices (with the exception of the Galaxy Nexus) require the Google USB Driver. The driver for the Galaxy Nexus is distributed by Samsung. All other Android devices should use the USB driver from their respective manufacturer.

Install the Google USB Driver package by starting the Android SDK Manager, and expanding the Extras folder, as can be seen in the follow screenshot:

Check the Google USB Driver box, and click the Apply Changes button. The driver files are downloaded to the following location:

The default path for a Xamarin.Android installation is:

Installing the USB Driver

After the USB drivers are downloaded, it is necessary to install them. To install the drivers on Windows 7:

1. Connect your device to the computer with a USB cable.

2. Right-click on the Computer from your desktop or Windows Explorer, and select Manage .

3. Select Devices in the left pane.

4. Locate and expand Other Devices in the right pane.

5. Right-click the device name and select Update Driver Software . This will launch the Hardware Update Wizard.

6. Select Browse my computer for driver software and click Next .

7. Click Browse and locate the USB driver folder (the Google USB driver is located in [Android SDK install path]\extras\google\usb_driver ).

8. Click Next to install the driver.

This guide describes the steps for switching to an internal distribution of OpenJDK. This distribution is intended for mobile development.

Overview

Beginning with Visual Studio 15.9 and Visual Studio for Mac 7.7, Visual Studio Tools for Xamarin has moved from Oracle’s JDK to a lightweight version of the OpenJDK that is intended solely for Android

development. This is a required migration as Oracle is ending support for commercial distribution of JDK 8 in 2019, and JDK 8 is a required dependency for all Android development.

The benefits of this move are:

You will always have an OpenJDK version that works for Android development. Downloading Oracle's JDK 9 or greater won’t affect the development experience. Reduced download size and footprint.

No more issues with 3rd party servers and installers.

If you’d like to move to the improved experience sooner, builds of the Microsoft Mobile OpenJDK distribution are available for you to test on both Windows and Mac. The setup process is described below, and you can revert back to the Oracle JDK at any time.

Download

The mobile OpenJDK distribution is automatically installed for you if you select the Android SDK packages in the Visual Studio installer on Windows.

On Mac, the mobile OpenJDK will be installed for you as part of the Android workload for new installs. For existing Visual Studio for Mac users, you will be prompted to install it as part of your update. The IDE will prompt you to move to the new JDK, and will switch to using it at the next restart.

Troubleshooting

If you encounter issues with the setup on Mac or Windows, you can take the following steps for manual setup: Check if OpenJDK is installed on the machine in the correct location:

Mac – $HOME/Library/Developer/Xamarin/jdk/microsoft_dist_openjdk_1.8.0.x Windows – C:\Program Files\Android\jdk\microsoft_dist_openjdk_1.8.0.x

Point the IDE to the new JDK:

Mac – Click Tools > SDK Manager > Locations and change the Java SDK (JDK) Location to the full path of the OpenJDK installation. In the following example, this path is set to

$HOME/Library/Developer/Xamarin/jdk/microsoft_dist_openjdk_1.8.0.9 but your version may be newer.

Windows – Click Tools > Options > Xamarin > Android Settings and change the Java Development Kit Location to the full path of the OpenJDK installation. In the following example, this path is set to

C:\Program Files\Android\jdk\microsoft_dist_openjdk_1.8.0.9 , but your version may be newer:

Known Issues

Package 'OpenJDKV1.RegKey,version=1.8.0.25,chip=x64' failed to install

This may be an issue in some corporate environments. OpenJDK is already on the machine - follow the troubleshooting steps above to point your IDE to the correct location.