Android P 系統應用無法對外置SD卡進行讀寫

1、frameworks/base/data/etc/platform.xml

     <permission name="android.permission.WRITE_MEDIA_STORAGE" >
-        <group gid="media_rw" />
+        <group gid="media_rw" /> 
+               <group gid="sdcard_rw" />  
     </permission>

2、frameworks/base/services/core/java/com/android/server/pm/PackageManagerService.java import static android.Manifest.permission.WRITE_EXTERNAL_STORAGE;
+import static android.Manifest.permission.WRITE_MEDIA_STORAGE;
 import static android.content.pm.PackageManager.CERT_INPUT_RAW_X509;
 import static android.content.pm.PackageManager.CERT_INPUT_SHA256;
 import static android.content.pm.PackageManager.COMPONENT_ENABLED_STATE_DEFAULT;
@@ -21329,6 +21332,13 @@ Slog.v(TAG, ":: stepped forward, applying functor at tag " + parser.getName());
                 if (Process.isIsolated(uid)) {
                     return Zygote.MOUNT_EXTERNAL_NONE;
                 }
+                               

+                if (checkUidPermission(WRITE_MEDIA_STORAGE, uid) == PERMISSION_GRANTED) {
+                    return Zygote.MOUNT_EXTERNAL_DEFAULT;
+               }

+                               
                 if (checkUidPermission(READ_EXTERNAL_STORAGE, uid) == PERMISSION_DENIED) {
                     return Zygote.MOUNT_EXTERNAL_DEFAULT;
                 }