Introduce action for setting up running Android emulator

Author: rmartin16

.github/actions/setup-android/action.yml

@@ -0,0 +1,38 @@
+name: Setup to Run Android Emulator
+description: Configures Linux to run the emulator and returns Briefcase args to run emulator.
+
+inputs:
+  emulator-config:
+    description: 'Configuration definition of emulator; defaults to {"avd":"beePhone"}.'
+    required: false
+    default: '{"avd":"beePhone"}'
+
+outputs:
+  briefcase-run-args:
+    value: ${{ steps.briefcase-run-args.outputs.run-args }}
+    description: "The version or branch of Briefcase that was installed."
+
+runs:
+  using: composite
+  steps:
+
+    - name: Enable KVM Access
+      shell: bash
+      run: |
+        echo 'KERNEL=="kvm", GROUP="kvm", MODE="0666", OPTIONS+="static_node=kvm"' \
+          | sudo tee /etc/udev/rules.d/99-kvm4all.rules
+        sudo udevadm control --reload-rules
+        sudo udevadm trigger --name-match=kvm
+
+    - name: Briefcase Run Arguments for Emulator
+      id: briefcase-run-args
+      env:
+        RUN_ARGS: >
+          --Xemulator=-no-window
+          --Xemulator=-no-snapshot
+          --Xemulator=-no-audio
+          --Xemulator=-no-boot-anim
+          --shutdown-on-exit
+      shell: bash
+      run: |
+        echo "run-args=$(printf -- "--device %q %s" '${{ inputs.emulator-config }}' "${RUN_ARGS}")" | tee -a ${GITHUB_OUTPUT}

.github/workflows/app-build-verify.yml

@@ -437,6 +437,11 @@ jobs:
         xvfb-run briefcase run linux flatpak
         briefcase package linux flatpak --adhoc-sign
 
+    - name: Setup Android Emulator
+      id: emulator-setup
+      if: startsWith(inputs.runner-os, 'ubuntu')
+      uses: ./beeware-.github/.github/actions/setup-android
+
     - name: Build Android App
       if: >
         contains(fromJSON('["", "Android"]'), inputs.target-platform)
@@ -452,19 +457,7 @@ jobs:
 
         # Only run Android app on Linux since it's duplicative (and slow) on other platforms
         if [ "${{ startsWith(inputs.runner-os, 'ubuntu') }}" = "true" ]; then
-          # allow access to KVM to run the emulator
-          echo 'KERNEL=="kvm", GROUP="kvm", MODE="0666", OPTIONS+="static_node=kvm"' \
-            | sudo tee /etc/udev/rules.d/99-kvm4all.rules
-          sudo udevadm control --reload-rules
-          sudo udevadm trigger --name-match=kvm
-
-          briefcase run android gradle \
-            --device '{"avd":"beePhone"}' \
-            --shutdown-on-exit \
-            --Xemulator=-no-window \
-            --Xemulator=-no-snapshot \
-            --Xemulator=-no-audio \
-            --Xemulator=-no-boot-anim
+          briefcase run android gradle ${{ steps.emulator-setup.outputs.briefcase-run-args }}
         fi
 
         briefcase package android gradle --adhoc-sign