Target API 28

Apps targeting API 28 by default do not grant permission for cleartext traffic,
so update the demo app to show a warning if loading an HTTP URI will fail. See
https://developer.android.com/about/versions/pie/android-9.0-changes-28 for
information on behavior changes in API 28.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=208204937

RELEASENOTES.md

@@ -5,6 +5,7 @@
 * Add a flag to opt-in to automatic audio focus handling via
   `SimpleExoPlayer.setAudioAttributes`.
 * Distribute Cronet extension via jCenter.
+* Set compileSdkVersion and targetSdkVersion to 28.
 * Add `AudioListener` for listening to changes in audio configuration during
   playback ([#3994](https://github.com/google/ExoPlayer/issues/3994)).
 * Improved seeking support:

constants.gradle

@@ -20,9 +20,9 @@ project.ext {
     // However, please note that the core media playback functionality provided
     // by the library requires API level 16 or greater.
     minSdkVersion = 14
-    targetSdkVersion = 27
-    compileSdkVersion = 27
-    buildToolsVersion = '27.0.3'
+    targetSdkVersion = 28
+    compileSdkVersion = 28
+    buildToolsVersion = '28.0.2'
     testSupportLibraryVersion = '0.5'
     supportLibraryVersion = '27.1.1'
     dexmakerVersion = '1.2'

demos/main/src/main/java/com/google/android/exoplayer2/demo/PlayerActivity.java

@@ -360,7 +360,11 @@ public class PlayerActivity extends Activity
         finish();
         return;
       }
-      if (Util.maybeRequestReadExternalStoragePermission(this, uris)) {
+      if (!Util.checkCleartextTrafficPermitted(uris)) {
+        showToast(R.string.error_cleartext_not_permitted);
+        return;
+      }
+      if (Util.maybeRequestReadExternalStoragePermission(/* activity= */ this, uris)) {
         // The player will be reinitialized if the permission is granted.
         return;
       }

demos/main/src/main/res/values/strings.xml

@@ -19,6 +19,8 @@
 
   <string name="unexpected_intent_action">Unexpected intent action: <xliff:g id="action">%1$s</xliff:g></string>
 
+  <string name="error_cleartext_not_permitted">Cleartext traffic not permitted</string>
+
   <string name="error_generic">Playback failed</string>
 
   <string name="error_unrecognized_abr_algorithm">Unrecognized ABR algorithm</string>

library/core/src/main/java/com/google/android/exoplayer2/util/Util.java

@@ -33,6 +33,7 @@ import android.os.Build;
 import android.os.Handler;
 import android.os.Looper;
 import android.os.Parcel;
+import android.security.NetworkSecurityPolicy;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.telephony.TelephonyManager;
@@ -184,6 +185,29 @@ public final class Util {
     return false;
   }
 
+  /**
+   * Returns whether it may be possible to load the given URIs based on the network security
+   * policy's cleartext traffic permissions.
+   *
+   * @param uris A list of URIs that will be loaded.
+   * @return Whether it may be possible to load the given URIs.
+   */
+  @TargetApi(24)
+  public static boolean checkCleartextTrafficPermitted(Uri... uris) {
+    if (Util.SDK_INT < 24) {
+      // We assume cleartext traffic is permitted.
+      return true;
+    }
+    for (Uri uri : uris) {
+      if ("http".equals(uri.getScheme())
+          && !NetworkSecurityPolicy.getInstance().isCleartextTrafficPermitted(uri.getHost())) {
+        // The security policy prevents cleartext traffic.
+        return false;
+      }
+    }
+    return true;
+  }
+
   /**
    * Returns true if the URI is a path to a local file or a reference to a local file.
    *