Android: Clean up lint warnings and other warnings to get build success

android/build.gradle

@@ -14,7 +14,7 @@ android {
     }
     compileSdkVersion 34
     defaultConfig {
-        minSdkVersion 21
+        minSdkVersion 22
         targetSdkVersion 33
         versionCode 1
         versionName "1.0"

android/src/main/java/io/grpc/android/AndroidChannelBuilder.java

@@ -217,7 +217,6 @@ private void configureNetworkMonitoring() {
         connectivityManager.registerDefaultNetworkCallback(defaultNetworkCallback);
         unregisterRunnable =
             new Runnable() {
-              @TargetApi(Build.VERSION_CODES.LOLLIPOP)
               @Override
               public void run() {
                 connectivityManager.unregisterNetworkCallback(defaultNetworkCallback);
@@ -231,7 +230,6 @@ public void run() {
         context.registerReceiver(networkReceiver, networkIntentFilter);
         unregisterRunnable =
             new Runnable() {
-              @TargetApi(Build.VERSION_CODES.LOLLIPOP)
               @Override
               public void run() {
                 context.unregisterReceiver(networkReceiver);

binder/build.gradle

@@ -13,7 +13,7 @@ android {
         targetCompatibility 1.8
     }
     defaultConfig {
-        minSdkVersion 21
+        minSdkVersion 22
         targetSdkVersion 33
         versionCode 1
         versionName "1.0"

binder/src/main/java/io/grpc/binder/SecurityPolicies.java

@@ -184,7 +184,6 @@ public Status checkAuthorization(int uid) {
    * Creates {@link SecurityPolicy} which checks if the app is a device owner app. See {@link
    * DevicePolicyManager}.
    */
-  @RequiresApi(18)
   public static io.grpc.binder.SecurityPolicy isDeviceOwner(Context applicationContext) {
     DevicePolicyManager devicePolicyManager =
         (DevicePolicyManager) applicationContext.getSystemService(Context.DEVICE_POLICY_SERVICE);
@@ -199,7 +198,6 @@ public static io.grpc.binder.SecurityPolicy isDeviceOwner(Context applicationCon
    * Creates {@link SecurityPolicy} which checks if the app is a profile owner app. See {@link
    * DevicePolicyManager}.
    */
-  @RequiresApi(21)
   public static SecurityPolicy isProfileOwner(Context applicationContext) {
     DevicePolicyManager devicePolicyManager =
         (DevicePolicyManager) applicationContext.getSystemService(Context.DEVICE_POLICY_SERVICE);

binder/src/main/java/io/grpc/binder/internal/ServiceBinding.java

@@ -193,18 +193,27 @@ private static Status bindInternal(
           bindResult = context.bindService(bindIntent, conn, flags);
           break;
         case BIND_SERVICE_AS_USER:
-          bindResult = context.bindServiceAsUser(bindIntent, conn, flags, targetUserHandle);
+          if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
+            bindResult = context.bindServiceAsUser(bindIntent, conn, flags, targetUserHandle);
+          } else {
+            return Status.INTERNAL.withDescription("Cross user Channel requires Android R+");
+          }
           break;
         case DEVICE_POLICY_BIND_SEVICE_ADMIN:
           DevicePolicyManager devicePolicyManager =
               (DevicePolicyManager) context.getSystemService(Context.DEVICE_POLICY_SERVICE);
-          bindResult =
-              devicePolicyManager.bindDeviceAdminServiceAsUser(
-                  channelCredentials.getDevicePolicyAdminComponentName(),
-                  bindIntent,
-                  conn,
-                  flags,
-                  targetUserHandle);
+          if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
+            bindResult =
+                devicePolicyManager.bindDeviceAdminServiceAsUser(
+                    channelCredentials.getDevicePolicyAdminComponentName(),
+                    bindIntent,
+                    conn,
+                    flags,
+                    targetUserHandle);
+          } else {
+            return Status.INTERNAL.withDescription(
+                "Device policy admin binding requires Android R+");
+          }
           break;
       }
       if (!bindResult) {

binder/src/test/java/io/grpc/binder/internal/ServiceBindingTest.java

@@ -29,6 +29,7 @@
 import android.content.Context;
 import android.content.Intent;
 import android.content.pm.ServiceInfo;
+import android.os.Build;
 import android.os.IBinder;
 import android.os.Parcel;
 import android.os.UserHandle;
@@ -327,6 +328,50 @@ public void testResolveNonExistentServiceWithTargetUserThrows() throws Exception
     assertThat(statusException.getStatus().getDescription()).contains("12345");
   }
 
+  @Test
+  @Config(sdk = 30)
+  public void testBindService_doesNotThrowInternalErrorWhenSdkAtLeastR() {
+    UserHandle userHandle = generateUserHandle(/* userId= */ 12345);
+    binding = newBuilder().setTargetUserHandle(userHandle).build();
+    binding.bind();
+    shadowOf(getMainLooper()).idle();
+
+    assertThat(Build.VERSION.SDK_INT).isEqualTo(Build.VERSION_CODES.R);
+    assertThat(observer.unboundReason).isNull();
+  }
+
+  @Test
+  @Config(sdk = 28)
+  public void testBindServiceAsUser_returnsErrorWhenSdkBelowR() {
+    UserHandle userHandle = generateUserHandle(/* userId= */ 12345);
+    binding = newBuilder().setTargetUserHandle(userHandle).build();
+    binding.bind();
+    shadowOf(getMainLooper()).idle();
+
+    assertThat(observer.unboundReason.getCode()).isEqualTo(Code.INTERNAL);
+    assertThat(observer.unboundReason.getDescription())
+        .isEqualTo("Cross user Channel requires Android R+");
+  }
+
+  @Test
+  @Config(sdk = 28)
+  public void testDevicePolicyBlind_returnsErrorWhenSdkBelowR() {
+    String deviceAdminClassName = "DevicePolicyAdmin";
+    ComponentName adminComponent = new ComponentName(appContext, deviceAdminClassName);
+    allowBindDeviceAdminForUser(appContext, adminComponent, 10);
+    binding =
+        newBuilder()
+            .setTargetUserHandle(UserHandle.getUserHandleForUid(10))
+            .setChannelCredentials(BinderChannelCredentials.forDevicePolicyAdmin(adminComponent))
+            .build();
+    binding.bind();
+    shadowOf(getMainLooper()).idle();
+
+    assertThat(observer.unboundReason.getCode()).isEqualTo(Code.INTERNAL);
+    assertThat(observer.unboundReason.getDescription())
+        .isEqualTo("Device policy admin binding requires Android R+");
+  }
+
   @Test
   @Config(sdk = 30)
   public void testBindWithDeviceAdmin() throws Exception {

cronet/build.gradle

@@ -14,7 +14,7 @@ android {
     namespace = 'io.grpc.cronet'
     compileSdkVersion 33
     defaultConfig {
-        minSdkVersion 21
+        minSdkVersion 22
         targetSdkVersion 33
         versionCode 1
         versionName "1.0"

lint.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<lint>
+    <!--
+      Suppress temporarily due to AAPT2 failures with SDK 35/36 on AGP 7.x.
+      Remove after AGP upgrade.
+    -->
+    <issue id="OldTargetApi" severity="ignore" />
+</lint>