build-tools to 31.0.0; SDK cmd-line tools to 5.0. (#174)

* Update build-tools to 31.0.0. Add API 31 emulator to workflow. Update SDK command-line tools to 5.0

* Update test fixture dependencies.

* Test API 31 with macos-11.

* Add android:exported to AndroidManifest.

* Format

test-fixture/app/build.gradle

@@ -2,13 +2,13 @@ apply plugin: 'com.android.application'
 apply plugin: 'kotlin-android'
 
 android {
-    compileSdkVersion 30
-    buildToolsVersion "30.0.3"
+    compileSdkVersion 31
+    buildToolsVersion "31.0.0"
 
     defaultConfig {
         applicationId "com.example.testapp"
         minSdkVersion 15
-        targetSdkVersion 30
+        targetSdkVersion 31
         versionCode 1
         versionName "1.0"
 
@@ -26,10 +26,7 @@ android {
 dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
     implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
-    implementation 'androidx.appcompat:appcompat:1.3.0'
-    implementation 'androidx.core:core-ktx:1.5.0'
-    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
-    testImplementation 'junit:junit:4.13'
-    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
-    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
+    implementation 'androidx.appcompat:appcompat:1.3.1'
+    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
 }

test-fixture/app/src/main/AndroidManifest.xml

@@ -9,7 +9,9 @@
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
         android:theme="@style/AppTheme">
-        <activity android:name="com.example.testapp.MainActivity">
+        <activity
+            android:name="com.example.testapp.MainActivity"
+            android:exported="true">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 

test-fixture/app/src/main/res/layout/activity_main.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
@@ -10,9 +10,6 @@
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="Hello World!"
-        app:layout_constraintBottom_toBottomOf="parent"
-        app:layout_constraintLeft_toLeftOf="parent"
-        app:layout_constraintRight_toRightOf="parent"
-        app:layout_constraintTop_toTopOf="parent" />
+        android:layout_gravity="center" />
 
-</androidx.constraintlayout.widget.ConstraintLayout>
+</FrameLayout>