fix lint warnings

Signed-off-by: Jens Mueller <tschenser@gmx.de>

src/main/java/com/owncloud/android/providers/DocumentsStorageProvider.java

@@ -179,7 +179,7 @@ public class DocumentsStorageProvider extends DocumentsProvider {
 
         boolean isLoading = false;
         if (parentFolder.isExpired()) {
-            final LoadChildrenTask task = new LoadChildrenTask(parentFolder, getContext(), loadChildrenCallback);
+            final LoadChildrenTask task = new LoadChildrenTask(parentFolder, loadChildrenCallback);
             task.executeOnExecutor(executor);
             resultCursor.setLoadingTask(task);
             isLoading = true;
@@ -735,12 +735,10 @@ public class DocumentsStorageProvider extends DocumentsProvider {
     static class LoadChildrenTask extends AsyncTask<Void, Void, RemoteOperationResult> {
 
         private final Document document;
-        private final Context context;
         private final OnTaskFinishedCallback<Document> callback;
 
-        LoadChildrenTask(Document document, Context context, OnTaskFinishedCallback<Document> callback) {
+        LoadChildrenTask(Document document, OnTaskFinishedCallback<Document> callback) {
             this.document = document;
-            this.context = context;
             this.callback = callback;
         }
 
@@ -749,7 +747,7 @@ public class DocumentsStorageProvider extends DocumentsProvider {
             Log.d(TAG, "run RefreshDocumentTask(), id=" + document.getDocumentId());
             return new RefreshFolderOperation(document.getFile(), System.currentTimeMillis(), false,
                                               false, true, document.getStorageManager(), document.getAccount(),
-                                              context).execute(document.getClient());
+                                              MainApp.getAppContext()).execute(document.getClient());
         }
 
         @Override
@@ -768,9 +766,9 @@ public class DocumentsStorageProvider extends DocumentsProvider {
 
     public class Document {
         private final FileDataStorageManager storageManager;
-        private final Long fileId;
+        private final long fileId;
 
-        Document(FileDataStorageManager storageManager, Long fileId) {
+        Document(FileDataStorageManager storageManager, long fileId) {
             this.storageManager = storageManager;
             this.fileId = fileId;
         }

src/main/java/org/nextcloud/providers/cursors/RootCursor.java

@@ -25,6 +25,7 @@ import android.annotation.TargetApi;
 import android.content.Context;
 import android.database.MatrixCursor;
 import android.os.Build;
+import android.provider.DocumentsContract;
 import android.provider.DocumentsContract.Root;
 
 import com.owncloud.android.R;
@@ -50,12 +51,17 @@ public class RootCursor extends MatrixCursor {
 
     public void addRoot(DocumentsStorageProvider.Document document, Context context) {
         Account account = document.getAccount();
+
+        int rootFlags = Root.FLAG_SUPPORTS_CREATE | Root.FLAG_SUPPORTS_RECENTS | Root.FLAG_SUPPORTS_SEARCH;
+        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
+            rootFlags = rootFlags | Root.FLAG_SUPPORTS_IS_CHILD;
+        }
+
         newRow().add(Root.COLUMN_ROOT_ID, account.name)
             .add(Root.COLUMN_DOCUMENT_ID, document.getDocumentId())
             .add(Root.COLUMN_SUMMARY, account.name)
             .add(Root.COLUMN_TITLE, context.getString(R.string.app_name))
             .add(Root.COLUMN_ICON, R.mipmap.ic_launcher)
-            .add(Root.COLUMN_FLAGS, Root.FLAG_SUPPORTS_CREATE | Root.FLAG_SUPPORTS_IS_CHILD |
-                Root.FLAG_SUPPORTS_RECENTS | Root.FLAG_SUPPORTS_SEARCH);
+            .add(Root.COLUMN_FLAGS, rootFlags);
     }
 }