Rich workspaces: can be null (if disabled), or string (empty or with content)

Signed-off-by: tobiasKaminsky <tobias@kaminsky.me>

scripts/analysis/lint-results.txt

@@ -1,2 +1,2 @@
 DO NOT TOUCH; GENERATED BY DRONE
-      <span class="mdl-layout-title">Lint Report: 94 warnings</span>
+      <span class="mdl-layout-title">Lint Report: 1 error and 94 warnings</span>

src/main/java/com/owncloud/android/ui/fragment/OCFileListBottomSheetDialog.java

@@ -23,7 +23,6 @@ package com.owncloud.android.ui.fragment;
 import android.content.Context;
 import android.os.Build;
 import android.os.Bundle;
-import android.text.TextUtils;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -176,10 +175,14 @@ public class OCFileListBottomSheetDialog extends BottomSheetDialog {
                                              user,
                                              MimeTypeUtil.MIMETYPE_TEXT_MARKDOWN) &&
             file != null) {
-            if (TextUtils.isEmpty(file.getRichWorkspace())) {
-                createRichWorkspace.setVisibility(View.VISIBLE);
-            } else {
+            // richWorkspace
+            // == "": no info set -> show button
+            // == null: disabled on server side -> hide button
+            // != "": info set -> hide button
+            if (file.getRichWorkspace() == null || !"".equals(file.getRichWorkspace())) {
                 createRichWorkspace.setVisibility(View.GONE);
+            } else {
+                createRichWorkspace.setVisibility(View.VISIBLE);
             }
         } else {
             createRichWorkspace.setVisibility(View.GONE);

src/main/java/com/owncloud/android/ui/preview/PreviewTextFragment.java

@@ -227,11 +227,15 @@ public abstract class PreviewTextFragment extends FileFragment implements Search
     }
 
     public static void setText(TextView textView,
-                               String text,
+                               @Nullable String text,
                                @Nullable OCFile file,
                                Activity activity,
                                boolean ignoreMimetype,
                                boolean preview) {
+        if (text == null) {
+            return;
+        }
+
         if ((ignoreMimetype || file != null && MimeTypeUtil.MIMETYPE_TEXT_MARKDOWN.equals(file.getMimeType()))
             && activity != null) {
             if (!preview) {

src/main/res/layout/file_details_sharing_fragment.xml

@@ -170,7 +170,8 @@
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:layout_marginTop="@dimen/standard_margin"
-            android:paddingRight="@dimen/standard_padding"
+            android:paddingStart="@dimen/zero"
+            android:paddingEnd="@dimen/standard_padding"
             android:orientation="horizontal">
 
             <ImageView