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

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

@@ -17,12 +17,15 @@
 package io.grpc.binder;
 
 import static android.content.Intent.URI_ANDROID_APP_SCHEME;
+import static android.content.Intent.URI_INTENT_SCHEME;
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkState;
 
+import android.annotation.SuppressLint;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
+import android.os.Build;
 import android.os.UserHandle;
 import com.google.common.base.Objects;
 import io.grpc.ExperimentalApi;
@@ -172,7 +175,10 @@ public String asAndroidAppUri() {
       // factory methods. Oddly, a ComponentName is not enough.
       intentForUri = intentForUri.cloneFilter().setPackage(getComponent().getPackageName());
     }
-    return intentForUri.toUri(URI_ANDROID_APP_SCHEME);
+    return intentForUri.toUri(
+              Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP_MR1
+              ? URI_ANDROID_APP_SCHEME
+              : URI_INTENT_SCHEME);
   }
 
   @Override

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 +193,21 @@ 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);
+          }
           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);
+                  (DevicePolicyManager) context.getSystemService(Context.DEVICE_POLICY_SERVICE);
+          if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            bindResult = devicePolicyManager.bindDeviceAdminServiceAsUser(
+                            channelCredentials.getDevicePolicyAdminComponentName(),
+                            bindIntent,
+                            conn,
+                            flags,
+                            targetUserHandle);
+          }
           break;
       }
       if (!bindResult) {

lint.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<lint>
+    <issue id="OldTargetApi" severity="ignore" />
+</lint>