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Installing on a Device

 

In Configuring an AVD, we describe how to set up a virtual device for debugging, but our ultimate target is for our programs to run on actual hardware. To install and execute programs on hardware you must

  1. Configure the mobile device and computer for hardware debugging,

  2. Connect the device to the development computer with a USB cable, and

  3. Transfer the executable to the device from the development computer.

Let us first describe how to configure for debugging and then how to transfer the executables.


On Android 4.2 and newer devices, the Developer options required in the following instructions are hidden by default. To make them available on those devices, go to Settings > About phone and tap Build number seven times. Then you should find Developer options displayed under Settings.

 

Configuring for Debugging on Actual Devices

We summarize the basics; a more extensive discussion may be found in the Android Run Apps on a Hardware Device document. Configuring the phone or tablet may be somewhat device-specific but should be similar to the following example for a Motorola Moto-X phone running Android 4.4.2.

  1. Go to Settings > {} Developer options and enable the USB debugging option. The following figure illustrates.




    Note: on devices running versions of Android older than 4.0 this option will instead be found under Settings > Applications > Development.


    "Stay awake" has also been checked to cause the screen display to stay on while the phone is charging on the USB cable; it is often useful in debugging for the screen to stay on, but this is not essential.


  2. Configuration of the development computer depends on the operating system:

  3. Connect the device to your development computer with a USB cable appropriate for the device. Note: it needs to be a USB data cable, not just a charging cable. Most Android charging cables are also data cables, but I have encountered some cheap ones that don't support data transfer.

  4. If things are well you will probably get a message on the computer that a USB device has been connected, which you can ignore unless a permission is requested. You will probably also get a popup on the device asking whether you will accept the connection. Say Yes. (There will probably also be a box to check if you want to allow connection to this computer in the future without having to give explicit permission.)

  5. To confirm that your device is connected after the above steps, issue at a shell prompt adb devices (where adb is in the platform-tools subdirectory of the SDK: we are assuming that you added this directory to your path earlier). Your device should appear in the list of devices that this command produces. For example, on my Fedora Linux system a typical result would be 

       [guidry@m33 sdk]$ adb devices
   List of devices attached 
   0146B5BA13010009        device
   emulator-5554   device
    In this output, emulator-5554 is an Android virtual device (emulator) configured as in Configuring an AVD (5554 is the port number associated with the virtual device), and 0146B5BA13010009 is a Samsung Galaxy Nexus phone that was connected to the computer according to the above instructions.

    6. You may also verify the devices connected by opening the DDSM perspective in Android Studio (Tools > Android > Android Device Monitor), and checking under the Devices tab. For example, the following image shows one hardware device and one emulator: a Huawei Nexus 6P phone running Android 6.0.1, and an AVD running Android 6.0 and connected to Android Studio on port 5554.


Now that the device is connected to the computer, Android packages that we have developed can be installed and debugged directly on the device. Let's see how to do that.

 

Installing and Debugging Applications on the Device

To install an application on a physical device connected to your development computer by a USB cable as described above, execute the app using Android Studio: click the Run button, or choose from the menu Run > Run 'app', and select the device for output in the resulting Select Deployment Target window, as illustrated in the following figure.




With the physical device selected, clicking OK will both install the app in the appropriate directory on the device and execute the application on the device if there are no errors.

 

Compatibility of Digital Signatures

For security, Android requires that all applications installed on physical devices be digitally signed by the developer. If you deploy apps for 3rd-party installation through channels such as the Google Play Store you must sign them with your own digital signature, but in development and debugging using Android Studio this isn't necessary because "under the hood" a debug certificate associated with the development machine is used automatically.

If you debug on a device using a particular computer, the app will be installed using the debug certificate associated with that machine. If you leave the app installed and then attempt to debug the same device on a different computer, you will get an error message in the logcat stream that the application signatures do not match. For example, 


[2010-06-08 10:34:06 - MapTutorial] Installing MapTutorial.apk...
[2010-06-08 10:34:08 - MapTutorial] Re-installation failed due to different application signatures.
[2010-06-08 10:34:08 - MapTutorial] You must perform a full uninstall of the application. 
                     WARNING: This will remove the application data!
[2010-06-08 10:34:08 - MapTutorial] Please execute 'adb uninstall com.lightcone.maptutorial' in a shell.
[2010-06-08 10:34:08 - MapTutorial] Launch canceled!

In this case, use the uninstall command described below first to remove the application from the device, and then repeat the install as described above.


More recent versions of the development tools may give a popup directly in Android Studio asking you if you want to uninstall the old app and install the one with the new signature.

 

Uninstalling Applications from the Device

To uninstall an application resident on a physical device connected by USB:

  1. Issue from the command line of a shell adb devices to get a list of currently-running devices and their serial numbers.

  2. Issue the command adb -s <serialNumber> uninstall appname, where <serialNumber> is the serial number for the device and appname is the fully qualified name of the app package. For example, 


    3. [guidry@m33 ~]$ adb devices
List of devices attached
TA5380467L      device
emulator-5554   device

[guidry@m33 ~]$ adb -s TA5380467L uninstall com.lightcone.recipes
Success
    If you know there is only a single device running, you can shorten the above to adb -d uninstall appname (the -d flag targets the only physical device running). For example, 

    [guidry@m33 workspaceAndroid]$ adb -d uninstall com.lightcone.recipes
Success
    (This returns an error if more than one physical device is running.)

The application can also be uninstalled manually from the device. The exact procedure will depend on the device but will likely be similar to: Go to Settings > Apps , select the application from the list that is populated, and press Uninstall.

Last modified: July 25, 2016

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