Add null annotations for fragments

app/src/main/java/acr/browser/lightning/fragment/AdvancedSettingsFragment.java

@@ -8,6 +8,7 @@ import android.content.DialogInterface;
 import android.os.Bundle;
 import android.preference.CheckBoxPreference;
 import android.preference.Preference;
+import android.support.annotation.NonNull;
 import android.support.v7.app.AlertDialog;
 
 import java.util.Arrays;
@@ -88,7 +89,7 @@ public class AdvancedSettingsFragment extends LightningPreferenceFragment implem
     }
 
     @Override
-    public boolean onPreferenceClick(Preference preference) {
+    public boolean onPreferenceClick(@NonNull Preference preference) {
         switch (preference.getKey()) {
             case SETTINGS_RENDERINGMODE:
                 renderPicker();
@@ -105,7 +106,7 @@ public class AdvancedSettingsFragment extends LightningPreferenceFragment implem
     }
 
     @Override
-    public boolean onPreferenceChange(Preference preference, Object newValue) {
+    public boolean onPreferenceChange(@NonNull Preference preference, Object newValue) {
         // switch preferences
         switch (preference.getKey()) {
             case SETTINGS_NEWWINDOW:

app/src/main/java/acr/browser/lightning/fragment/BookmarkSettingsFragment.java

@@ -12,6 +12,8 @@ import android.os.Bundle;
 import android.os.Environment;
 import android.preference.Preference;
 import android.preference.PreferenceFragment;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
 import android.support.v7.app.AlertDialog;
 
 import java.io.File;
@@ -27,8 +29,11 @@ import acr.browser.lightning.app.BrowserApp;
 import acr.browser.lightning.database.BookmarkLocalSync;
 import acr.browser.lightning.database.BookmarkManager;
 import acr.browser.lightning.database.HistoryItem;
+
 import com.anthonycr.grant.PermissionsManager;
 import com.anthonycr.grant.PermissionsResultAction;
+
+import acr.browser.lightning.utils.Preconditions;
 import acr.browser.lightning.utils.Utils;
 
 public class BookmarkSettingsFragment extends PreferenceFragment implements Preference.OnPreferenceClickListener {
@@ -37,12 +42,13 @@ public class BookmarkSettingsFragment extends PreferenceFragment implements Pref
     private static final String SETTINGS_IMPORT = "import_bookmark";
     private static final String SETTINGS_IMPORT_BROWSER = "import_browser";
 
-    private Activity mActivity;
-    @Inject
-    BookmarkManager mBookmarkManager;
+    @Nullable private Activity mActivity;
+
+    @Inject BookmarkManager mBookmarkManager;
     private File[] mFileList;
     private String[] mFileNameList;
-    private BookmarkLocalSync mSync;
+    @Nullable private BookmarkLocalSync mSync;
+
     private static final String[] REQUIRED_PERMISSIONS = new String[]{
             Manifest.permission.READ_EXTERNAL_STORAGE,
             Manifest.permission.WRITE_EXTERNAL_STORAGE
@@ -52,7 +58,7 @@ public class BookmarkSettingsFragment extends PreferenceFragment implements Pref
 
     private class ImportBookmarksTask extends AsyncTask<Void, Void, Integer> {
 
-        private final WeakReference<Activity> mActivityReference;
+        @NonNull private final WeakReference<Activity> mActivityReference;
 
         public ImportBookmarksTask(Activity activity) {
             mActivityReference = new WeakReference<>(activity);
@@ -61,10 +67,10 @@ public class BookmarkSettingsFragment extends PreferenceFragment implements Pref
         @Override
         protected Integer doInBackground(Void... params) {
             List<HistoryItem> list = null;
-            if (mSync.isStockSupported()) {
-                list = mSync.getBookmarksFromStockBrowser();
-            } else if (mSync.isChromeSupported()) {
-                list = mSync.getBookmarksFromChrome();
+            if (getSync().isStockSupported()) {
+                list = getSync().getBookmarksFromStockBrowser();
+            } else if (getSync().isChromeSupported()) {
+                list = getSync().getBookmarksFromChrome();
             }
             int count = 0;
             if (list != null && !list.isEmpty()) {
@@ -86,6 +92,16 @@ public class BookmarkSettingsFragment extends PreferenceFragment implements Pref
         }
     }
 
+    @NonNull
+    private BookmarkLocalSync getSync() {
+        Preconditions.checkNonNull(mActivity);
+        if (mSync == null) {
+            mSync = new BookmarkLocalSync(mActivity);
+        }
+
+        return mSync;
+    }
+
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -94,6 +110,7 @@ public class BookmarkSettingsFragment extends PreferenceFragment implements Pref
         addPreferencesFromResource(R.xml.preference_bookmarks);
 
         mActivity = getActivity();
+        mSync = new BookmarkLocalSync(mActivity);
 
         initPrefs();
 
@@ -117,8 +134,6 @@ public class BookmarkSettingsFragment extends PreferenceFragment implements Pref
         Preference exportpref = findPreference(SETTINGS_EXPORT);
         Preference importpref = findPreference(SETTINGS_IMPORT);
 
-        mSync = new BookmarkLocalSync(mActivity);
-
         exportpref.setOnPreferenceClickListener(this);
         importpref.setOnPreferenceClickListener(this);
 
@@ -129,13 +144,13 @@ public class BookmarkSettingsFragment extends PreferenceFragment implements Pref
         @Override
         public void run() {
             Preference importStock = findPreference(SETTINGS_IMPORT_BROWSER);
-            importStock.setEnabled(mSync.isStockSupported() || mSync.isChromeSupported());
+            importStock.setEnabled(getSync().isStockSupported() || getSync().isChromeSupported());
             importStock.setOnPreferenceClickListener(BookmarkSettingsFragment.this);
         }
     };
 
     @Override
-    public boolean onPreferenceClick(Preference preference) {
+    public boolean onPreferenceClick(@NonNull Preference preference) {
         switch (preference.getKey()) {
             case SETTINGS_EXPORT:
                 PermissionsManager.getInstance().requestPermissionsIfNecessaryForResult(getActivity(), REQUIRED_PERMISSIONS,
@@ -175,7 +190,7 @@ public class BookmarkSettingsFragment extends PreferenceFragment implements Pref
         }
     }
 
-    private void loadFileList(File path) {
+    private void loadFileList(@Nullable File path) {
         File file;
         if (path != null) {
             file = path;
@@ -208,7 +223,7 @@ public class BookmarkSettingsFragment extends PreferenceFragment implements Pref
     private static class SortName implements Comparator<File> {
 
         @Override
-        public int compare(File a, File b) {
+        public int compare(@NonNull File a, @NonNull File b) {
             if (a.isDirectory() && b.isDirectory())
                 return a.getName().compareTo(b.getName());
 

app/src/main/java/acr/browser/lightning/fragment/BookmarksFragment.java

@@ -146,7 +146,7 @@ public class BookmarksFragment extends Fragment implements View.OnClickListener,
 
     @Nullable
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
         final View view = inflater.inflate(R.layout.bookmark_drawer, container, false);
         mBookmarksListView = (ListView) view.findViewById(R.id.right_drawer_list);
         mBookmarksListView.setOnItemClickListener(mItemClickListener);
@@ -187,14 +187,14 @@ public class BookmarksFragment extends Fragment implements View.OnClickListener,
     }
 
     @Subscribe
-    public void addBookmark(final BrowserEvents.BookmarkAdded event) {
+    public void addBookmark(@NonNull final BrowserEvents.BookmarkAdded event) {
         updateBookmarkIndicator(event.url);
         String folder = mBookmarkManager.getCurrentFolder();
         setBookmarkDataSet(mBookmarkManager.getBookmarksFromFolder(folder, true), false);
     }
 
     @Subscribe
-    public void currentPageInfo(final BrowserEvents.CurrentPageUrl event) {
+    public void currentPageInfo(@NonNull final BrowserEvents.CurrentPageUrl event) {
         updateBookmarkIndicator(event.url);
         String folder = mBookmarkManager.getCurrentFolder();
         setBookmarkDataSet(mBookmarkManager.getBookmarksFromFolder(folder, true), false);
@@ -227,7 +227,7 @@ public class BookmarksFragment extends Fragment implements View.OnClickListener,
     }
 
     @Subscribe
-    public void bookmarkDeleted(final BookmarkEvents.Deleted event) {
+    public void bookmarkDeleted(@NonNull final BookmarkEvents.Deleted event) {
         mBookmarks.remove(event.item);
         if (event.item.isFolder()) {
             setBookmarkDataSet(mBookmarkManager.getBookmarksFromFolder(null, true), false);
@@ -236,7 +236,7 @@ public class BookmarksFragment extends Fragment implements View.OnClickListener,
         }
     }
 
-    private void setBookmarkDataSet(List<HistoryItem> items, boolean animate) {
+    private void setBookmarkDataSet(@NonNull List<HistoryItem> items, boolean animate) {
         mBookmarks.clear();
         mBookmarks.addAll(items);
         mBookmarkAdapter.notifyDataSetChanged();
@@ -294,7 +294,7 @@ public class BookmarksFragment extends Fragment implements View.OnClickListener,
         buttonImage.setColorFilter(mIconColor, PorterDuff.Mode.SRC_IN);
     }
 
-    private void handleLongPress(final HistoryItem item) {
+    private void handleLongPress(@NonNull final HistoryItem item) {
         if (item.isFolder()) {
             mBookmarksDialogBuilder.showBookmarkFolderLongPressedDialog(getContext(), item);
         } else {
@@ -303,7 +303,7 @@ public class BookmarksFragment extends Fragment implements View.OnClickListener,
     }
 
     @Override
-    public void onClick(View v) {
+    public void onClick(@NonNull View v) {
         switch (v.getId()) {
             case R.id.action_add_bookmark:
                 mEventBus.post(new BookmarkEvents.ToggleBookmarkForCurrentPage());
@@ -338,7 +338,7 @@ public class BookmarksFragment extends Fragment implements View.OnClickListener,
 
         final Context context;
 
-        public BookmarkViewAdapter(Context context, List<HistoryItem> data) {
+        public BookmarkViewAdapter(Context context, @NonNull List<HistoryItem> data) {
             super(context, R.layout.bookmark_list_item, data);
             this.context = context;
         }

app/src/main/java/acr/browser/lightning/fragment/DisplaySettingsFragment.java

@@ -8,6 +8,7 @@ import android.content.DialogInterface;
 import android.os.Bundle;
 import android.preference.CheckBoxPreference;
 import android.preference.Preference;
+import android.support.annotation.NonNull;
 import android.support.v7.app.AlertDialog;
 import android.view.Gravity;
 import android.view.LayoutInflater;
@@ -83,7 +84,7 @@ public class DisplaySettingsFragment extends LightningPreferenceFragment impleme
     }
 
     @Override
-    public boolean onPreferenceClick(Preference preference) {
+    public boolean onPreferenceClick(@NonNull Preference preference) {
         switch (preference.getKey()) {
             case SETTINGS_THEME:
                 themePicker();
@@ -97,7 +98,7 @@ public class DisplaySettingsFragment extends LightningPreferenceFragment impleme
     }
 
     @Override
-    public boolean onPreferenceChange(Preference preference, Object newValue) {
+    public boolean onPreferenceChange(@NonNull Preference preference, Object newValue) {
         // switch preferences
         switch (preference.getKey()) {
             case SETTINGS_HIDESTATUSBAR:

app/src/main/java/acr/browser/lightning/fragment/GeneralSettingsFragment.java

@@ -10,6 +10,7 @@ import android.os.Bundle;
 import android.os.Environment;
 import android.preference.CheckBoxPreference;
 import android.preference.Preference;
+import android.support.annotation.NonNull;
 import android.support.v4.content.ContextCompat;
 import android.support.v7.app.AlertDialog;
 import android.text.Editable;
@@ -503,7 +504,7 @@ public class GeneralSettingsFragment extends LightningPreferenceFragment impleme
     }
 
     @Override
-    public boolean onPreferenceClick(Preference preference) {
+    public boolean onPreferenceClick(@NonNull Preference preference) {
         switch (preference.getKey()) {
             case SETTINGS_PROXY:
                 proxyChoicePicker();
@@ -526,7 +527,7 @@ public class GeneralSettingsFragment extends LightningPreferenceFragment impleme
     }
 
     @Override
-    public boolean onPreferenceChange(Preference preference, Object newValue) {
+    public boolean onPreferenceChange(@NonNull Preference preference, Object newValue) {
         boolean checked = false;
         if (newValue instanceof Boolean) {
             checked = (Boolean) newValue;
@@ -586,7 +587,7 @@ public class GeneralSettingsFragment extends LightningPreferenceFragment impleme
         public void onTextChanged(CharSequence s, int start, int before, int count) {}
 
         @Override
-        public void afterTextChanged(Editable s) {
+        public void afterTextChanged(@NonNull Editable s) {
             if (!DownloadHandler.isWriteAccessAvailable(s.toString())) {
                 this.getDownload.setTextColor(this.errorColor);
             } else {

app/src/main/java/acr/browser/lightning/fragment/PrivacySettingsFragment.java

@@ -11,6 +11,7 @@ import android.os.Handler;
 import android.os.Message;
 import android.preference.CheckBoxPreference;
 import android.preference.Preference;
+import android.support.annotation.NonNull;
 import android.support.v7.app.AlertDialog;
 import android.webkit.WebView;
 
@@ -114,7 +115,7 @@ public class PrivacySettingsFragment extends LightningPreferenceFragment impleme
         }
 
         @Override
-        public void handleMessage(Message msg) {
+        public void handleMessage(@NonNull Message msg) {
             switch (msg.what) {
                 case 1:
                     Utils.showSnackbar(mHandlerContext, R.string.message_clear_history);
@@ -128,7 +129,7 @@ public class PrivacySettingsFragment extends LightningPreferenceFragment impleme
     }
 
     @Override
-    public boolean onPreferenceClick(Preference preference) {
+    public boolean onPreferenceClick(@NonNull Preference preference) {
         switch (preference.getKey()) {
             case SETTINGS_CLEARCACHE:
                 clearCache();
@@ -209,7 +210,7 @@ public class PrivacySettingsFragment extends LightningPreferenceFragment impleme
     }
 
     @Override
-    public boolean onPreferenceChange(Preference preference, Object newValue) {
+    public boolean onPreferenceChange(@NonNull Preference preference, Object newValue) {
         switch (preference.getKey()) {
             case SETTINGS_LOCATION:
                 mPreferenceManager.setLocationEnabled((Boolean) newValue);

app/src/main/java/acr/browser/lightning/fragment/TabsFragment.java

@@ -69,8 +69,7 @@ public class TabsFragment extends Fragment implements View.OnClickListener, View
     private boolean mColorMode = true;
     private boolean mShowInNavigationDrawer;
 
-    private RecyclerView mRecyclerView;
-    private LightningViewAdapter mTabsAdapter;
+    @Nullable private LightningViewAdapter mTabsAdapter;
     private UIController mUiController;
 
     @Inject TabsManager tabsManager;
@@ -99,7 +98,7 @@ public class TabsFragment extends Fragment implements View.OnClickListener, View
 
     @Nullable
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
         final View view;
         final LayoutManager layoutManager;
         if (mShowInNavigationDrawer) {
@@ -114,11 +113,11 @@ public class TabsFragment extends Fragment implements View.OnClickListener, View
             view = inflater.inflate(R.layout.tab_strip, container, false);
             layoutManager = new LinearLayoutManager(getContext(), LinearLayoutManager.HORIZONTAL, false);
         }
-        mRecyclerView = (RecyclerView) view.findViewById(R.id.tabs_list);
-        mRecyclerView.setLayoutManager(layoutManager);
+        RecyclerView recyclerView = (RecyclerView) view.findViewById(R.id.tabs_list);
+        recyclerView.setLayoutManager(layoutManager);
         mTabsAdapter = new LightningViewAdapter(mShowInNavigationDrawer);
-        mRecyclerView.setAdapter(mTabsAdapter);
-        mRecyclerView.setHasFixedSize(true);
+        recyclerView.setAdapter(mTabsAdapter);
+        recyclerView.setHasFixedSize(true);
         return view;
     }
 
@@ -134,7 +133,6 @@ public class TabsFragment extends Fragment implements View.OnClickListener, View
     @Override
     public void onDestroyView() {
         super.onDestroyView();
-        mRecyclerView = null;
         mTabsAdapter = null;
     }
 
@@ -148,8 +146,10 @@ public class TabsFragment extends Fragment implements View.OnClickListener, View
     public void onResume() {
         super.onResume();
         // Force adapter refresh
+        if (mTabsAdapter != null) {
             mTabsAdapter.notifyDataSetChanged();
         }
+    }
 
     @Override
     public void onStop() {
@@ -165,7 +165,7 @@ public class TabsFragment extends Fragment implements View.OnClickListener, View
     }
 
     @Override
-    public void onClick(View v) {
+    public void onClick(@NonNull View v) {
         switch (v.getId()) {
             case R.id.new_tab_button:
                 mBus.post(new TabEvents.NewTab());
@@ -184,7 +184,7 @@ public class TabsFragment extends Fragment implements View.OnClickListener, View
     }
 
     @Override
-    public boolean onLongClick(View v) {
+    public boolean onLongClick(@NonNull View v) {
         switch (v.getId()) {
             case R.id.action_new_tab:
                 mBus.post(new TabEvents.NewTabLongPress());
@@ -198,9 +198,9 @@ public class TabsFragment extends Fragment implements View.OnClickListener, View
     public class LightningViewAdapter extends RecyclerView.Adapter<LightningViewAdapter.LightningViewHolder> {
 
         private final int mLayoutResourceId;
-        private final Drawable mBackgroundTabDrawable;
-        private final Drawable mForegroundTabDrawable;
-        private final Bitmap mForegroundTabBitmap;
+        @Nullable private final Drawable mBackgroundTabDrawable;
+        @Nullable private final Drawable mForegroundTabDrawable;
+        @Nullable private final Bitmap mForegroundTabBitmap;
         private ColorMatrix mColorMatrix;
         private Paint mPaint;
         private ColorFilter mFilter;
@@ -229,15 +229,16 @@ public class TabsFragment extends Fragment implements View.OnClickListener, View
             }
         }
 
+        @NonNull
         @Override
-        public LightningViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
+        public LightningViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
             LayoutInflater inflater = LayoutInflater.from(viewGroup.getContext());
             View view = inflater.inflate(mLayoutResourceId, viewGroup, false);
             return new LightningViewHolder(view);
         }
 
         @Override
-        public void onBindViewHolder(final LightningViewHolder holder, int position) {
+        public void onBindViewHolder(@NonNull final LightningViewHolder holder, int position) {
             holder.exitButton.setTag(position);
 
             ViewCompat.jumpDrawablesToCurrentState(holder.exitButton);
@@ -293,7 +294,7 @@ public class TabsFragment extends Fragment implements View.OnClickListener, View
             return tabsManager.size();
         }
 
-        public Bitmap getDesaturatedBitmap(Bitmap favicon) {
+        public Bitmap getDesaturatedBitmap(@NonNull Bitmap favicon) {
             Bitmap grayscaleBitmap = Bitmap.createBitmap(favicon.getWidth(),
                     favicon.getHeight(), Bitmap.Config.ARGB_8888);
 
@@ -312,7 +313,7 @@ public class TabsFragment extends Fragment implements View.OnClickListener, View
 
         public class LightningViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener, View.OnLongClickListener {
 
-            public LightningViewHolder(View view) {
+            public LightningViewHolder(@NonNull View view) {
                 super(view);
                 txtTitle = (TextView) view.findViewById(R.id.textTab);
                 favicon = (ImageView) view.findViewById(R.id.faviconTab);
@@ -326,11 +327,11 @@ public class TabsFragment extends Fragment implements View.OnClickListener, View
                 layout.setOnLongClickListener(this);
             }
 
-            final TextView txtTitle;
-            final ImageView favicon;
-            final ImageView exit;
-            final FrameLayout exitButton;
-            final LinearLayout layout;
+            @NonNull final TextView txtTitle;
+            @NonNull final ImageView favicon;
+            @NonNull final ImageView exit;
+            @NonNull final FrameLayout exitButton;
+            @NonNull final LinearLayout layout;
 
             @Override
             public void onClick(View v) {