Update GitHub Actions workflows

.github/workflows/android.yml

@@ -1,24 +1,62 @@
 name: Android CI
 
 on:
- push:
-  branches:
-   - main
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
 
 jobs:
-  build:
+  lint:
+    name: Spotless check
+    runs-on: ubuntu-18.04
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v2
+      - name: Set up JDK
+        uses: actions/setup-java@v1
+        with:
+          java-version: 11
+      - name: spotless
+        run: ./gradlew spotlessCheck
 
-    runs-on: ubuntu-latest
+  api_check:
+    name: API check
+    runs-on: ubuntu-18.04
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v2
+      - name: Set up JDK
+        uses: actions/setup-java@v1
+        with:
+          java-version: 11
+      - name: API check
+        run: ./gradlew apiCheck
 
+  build:
+    runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
-    - name: set up JDK 1.8
-      uses: actions/setup-java@v1
-      with:
-        java-version: 1.8
-    - name: Make Gradle executable
-      run: chmod +x ./gradlew
-    - name: Build with Gradle
-      run: ./gradlew build
-    - name: Build Debug APK
-      run: ./gradlew assembleDebug
+      - uses: actions/checkout@v2
+
+      - name: set up JDK
+        uses: actions/setup-java@v1
+        with:
+          java-version: 11
+
+      - name: Cache Gradle and wrapper
+        uses: actions/cache@v2
+        with:
+          path: |
+            ~/.gradle/caches
+            ~/.gradle/wrapper
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+
+      - name: Make Gradle executable
+        run: chmod +x ./gradlew
+
+      - name: Build with Gradle
+        run: ./gradlew build