Update android example gradle and target sdk version.

The build tools is update android sdk to 31, consistent with it.

Bug: None
Change-Id: I873d13481d24009d7b730b7adeeffd2362145ccd
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/263800
Reviewed-by: Xavier Lepaul‎ <xalep@webrtc.org>
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Commit-Queue: Per Kjellander <perkj@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#37050}

examples/BUILD.gn

@@ -96,7 +96,7 @@ if (is_android) {
     apk_name = "AppRTCMobile"
     android_manifest = "androidapp/AndroidManifest.xml"
     min_sdk_version = 21
-    target_sdk_version = 29
+    target_sdk_version = 31
 
     deps = [
       ":AppRTCMobile_javalib",
@@ -206,7 +206,7 @@ if (is_android) {
     apk_name = "AppRTCMobileTest"
     android_manifest = "androidtests/AndroidManifest.xml"
     min_sdk_version = 21
-    target_sdk_version = 21
+    target_sdk_version = 31
 
     sources = [
       "androidtests/src/org/appspot/apprtc/test/PeerConnectionClientTest.java",

examples/aarproject/app/build.gradle

@@ -1,11 +1,11 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 27
+    compileSdkVersion 31
     defaultConfig {
         applicationId "org.appspot.apprtc"
         minSdkVersion 21
-        targetSdkVersion 21
+        targetSdkVersion 31
         versionCode 1
         versionName "1.0"
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"

examples/aarproject/build.gradle

@@ -4,10 +4,10 @@ buildscript {
 
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.0.0'
+        classpath "com.android.tools.build:gradle:7.0.3"
 
 
         // NOTE: Do not place your application dependencies here; they belong
@@ -18,7 +18,7 @@ buildscript {
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 

examples/androidapp/AndroidManifest.xml

@@ -8,7 +8,6 @@
     <uses-feature android:name="android.hardware.camera" />
     <uses-feature android:name="android.hardware.camera.autofocus" />
     <uses-feature android:glEsVersion="0x00020000" android:required="true" />
-    <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="29" />
 
     <uses-permission android:name="android.permission.CAMERA" />
     <uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
@@ -30,7 +29,8 @@
         <activity android:name="ConnectActivity"
                   android:label="@string/app_name"
                   android:windowSoftInputMode="adjustPan"
-                  android:theme="@style/AppTheme">
+                  android:theme="@style/AppTheme"
+                  android:exported="true">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN"/>
                 <category android:name="android.intent.category.LAUNCHER"/>

examples/androidnativeapi/AndroidManifest.xml

@@ -2,7 +2,6 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="org.webrtc.examples.androidnativeapi">
 
-  <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="27" />
 
   <uses-permission android:name="android.permission.INTERNET" />
   <uses-permission android:name="android.permission.CAMERA" />
@@ -11,7 +10,8 @@
     android:allowBackup="true"
     android:label="@string/app_name"
     android:supportsRtl="true">
-    <activity android:name=".MainActivity">
+    <activity android:name=".MainActivity"
+      android:exported="true">
       <intent-filter>
         <action android:name="android.intent.action.MAIN" />
 

examples/androidnativeapi/BUILD.gn

@@ -6,7 +6,7 @@ if (is_android) {
     apk_name = "androidnativeapi"
     android_manifest = "AndroidManifest.xml"
     min_sdk_version = 21
-    target_sdk_version = 27
+    target_sdk_version = 31
 
     sources = [
       "java/org/webrtc/examples/androidnativeapi/CallClient.java",

examples/androidtests/AndroidManifest.xml

@@ -14,7 +14,6 @@
       package="org.appspot.apprtc.test">
 
     <uses-permission android:name="android.permission.RUN_INSTRUMENTATION" />
-    <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="21" />
 
     <application>
         <uses-library android:name="android.test.runner" />

examples/androidvoip/AndroidManifest.xml

@@ -13,7 +13,6 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="org.webrtc.examples.androidvoip">
 
-  <uses-sdk android:minSdkVersion="21" android:targetSdkVersion="27" />
 
   <uses-permission android:name="android.permission.INTERNET" />
   <uses-permission android:name="android.permission.RECORD_AUDIO" />
@@ -27,7 +26,8 @@
     android:label="@string/app_name"
     android:supportsRtl="true">
     <activity android:name=".MainActivity"
-              android:windowSoftInputMode="stateHidden">
+      android:windowSoftInputMode="stateHidden"
+      android:exported="true">
       <intent-filter>
         <action android:name="android.intent.action.MAIN" />
         <category android:name="android.intent.category.LAUNCHER" />

examples/androidvoip/BUILD.gn

@@ -14,7 +14,7 @@ if (is_android) {
     apk_name = "androidvoip"
     android_manifest = "AndroidManifest.xml"
     min_sdk_version = 21
-    target_sdk_version = 27
+    target_sdk_version = 31
 
     sources = [
       "java/org/webrtc/examples/androidvoip/MainActivity.java",