Fix travis-ci with the latest changes (#37)

* Update build-tools and platform version in travis.yml

* Use java11 in travis config file

* Export MainActivity to make it Android 12 friendly

* Ignore Instantiatable lint error

.travis.yml

@@ -1,6 +1,6 @@
+os: linux
 language: android
-dist: trusty
-sudo: required
+jdk: openjdk11
 
 android:
   components:
@@ -11,11 +11,18 @@ android:
     - 'android-sdk-preview-license-52d11cd2'
     - 'android-sdk-license-.+'
     - 'google-gdk-license-.+'
+env:
+  global:
+    - TARGET_VERSION=30
+    - ANDROID_BUILD_TOOLS_VERSION=31.0.0
+    - ANDROID_HOME=~/android-sdk
 
 before_install:
   - touch $HOME/.android/repositories.cfg
-  - yes | sdkmanager "platforms;android-30"
-  - yes | sdkmanager "build-tools;30.0.3"
+  - wget "https://dl.google.com/android/repository/commandlinetools-linux-7302050_latest.zip" -O commandlinetools.zip
+  - unzip commandlinetools.zip -d $ANDROID_HOME/
+  - yes | $ANDROID_HOME/cmdline-tools/bin/sdkmanager "platforms;android-${TARGET_VERSION}" --sdk_root=$ANDROID_HOME
+  - yes | $ANDROID_HOME/cmdline-tools/bin/sdkmanager "build-tools;${ANDROID_BUILD_TOOLS_VERSION}" --sdk_root=$ANDROID_HOME
 
 before_cache:
   - rm -f  $HOME/.gradle/caches/modules-2/modules-2.lock

platform/mobile/src/main/AndroidManifest.xml

@@ -13,11 +13,12 @@
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="false"
         android:theme="@style/AppTheme"
-        tools:ignore="GoogleAppIndexingWarning">
+        tools:ignore="GoogleAppIndexingWarning, Instantiatable">
 
         <activity
             android:name=".MainActivity"
-            android:windowSoftInputMode="adjustPan">
+            android:windowSoftInputMode="adjustPan"
+            android:exported="true">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />