Improve nullability coverage (#514)

* Switch to in-built RV divider

* Switch getActivity calls to requireActivity

This enforces non-null activity and throws a proper exception when it is
null for some reason.

Signed-off-by: Harsh Shandilya <msfjarvis@gmail.com>

5 files changed, 38 insertions, 88 deletions

diff --git a/app/src/main/java/com/zeapo/pwdstore/DividerItemDecoration.java b/app/src/main/java/com/zeapo/pwdstore/DividerItemDecoration.java
deleted file mode 100644
index 93673902..00000000
--- a/app/src/main/java/com/zeapo/pwdstore/DividerItemDecoration.java
+++ /dev/null
@@ -1,52 +0,0 @@
-package com.zeapo.pwdstore;
-
-import android.content.Context;
-import android.content.res.TypedArray;
-import android.graphics.Canvas;
-import android.graphics.drawable.Drawable;
-import android.view.View;
-import androidx.annotation.NonNull;
-import androidx.core.content.ContextCompat;
-import androidx.recyclerview.widget.RecyclerView;
-
-class DividerItemDecoration extends RecyclerView.ItemDecoration {
-
-    private static final int[] ATTRS = new int[]{android.R.attr.listDivider};
-
-    private Drawable mDivider;
-
-    /**
-     * Default divider will be used
-     */
-    public DividerItemDecoration(Context context) {
-        final TypedArray styledAttributes = context.obtainStyledAttributes(ATTRS);
-        mDivider = styledAttributes.getDrawable(0);
-        styledAttributes.recycle();
-    }
-
-    /**
-     * Custom divider will be used
-     */
-    DividerItemDecoration(Context context, int resId) {
-        mDivider = ContextCompat.getDrawable(context, resId);
-    }
-
-    @Override
-    public void onDraw(@NonNull Canvas c, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
-        int left = parent.getPaddingLeft();
-        int right = parent.getWidth() - parent.getPaddingRight();
-
-        int childCount = parent.getChildCount();
-        for (int i = 0; i < childCount; i++) {
-            View child = parent.getChildAt(i);
-
-            RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
-
-            int top = child.getBottom() + params.bottomMargin;
-            int bottom = top + mDivider.getIntrinsicHeight();
-
-            mDivider.setBounds(left, top, right, bottom);
-            mDivider.draw(c);
-        }
-    }
-}
diff --git a/app/src/main/java/com/zeapo/pwdstore/PasswordFragment.java b/app/src/main/java/com/zeapo/pwdstore/PasswordFragment.java
index 63211af0..b8d7bd8d 100644
--- a/app/src/main/java/com/zeapo/pwdstore/PasswordFragment.java
+++ b/app/src/main/java/com/zeapo/pwdstore/PasswordFragment.java
@@ -11,6 +11,7 @@ import android.view.ViewGroup;
 import androidx.annotation.NonNull;
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.fragment.app.Fragment;
+import androidx.recyclerview.widget.DividerItemDecoration;
 import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
 import com.google.android.material.floatingactionbutton.FloatingActionButton;
@@ -51,12 +52,12 @@ public class PasswordFragment extends Fragment {
         super.onCreate(savedInstanceState);
         String path = getArguments().getString("Path");
 
-        settings = PreferenceManager.getDefaultSharedPreferences(getActivity());
+        settings = PreferenceManager.getDefaultSharedPreferences(requireActivity());
         passListStack = new Stack<>();
         scrollPosition = new Stack<>();
         pathStack = new Stack<>();
-        recyclerAdapter = new PasswordRecyclerAdapter((PasswordStore) getActivity(), mListener,
-                PasswordRepository.getPasswords(new File(path), PasswordRepository.getRepositoryDirectory(getActivity()), getSortOrder()));
+        recyclerAdapter = new PasswordRecyclerAdapter((PasswordStore) requireActivity(), mListener,
+                PasswordRepository.getPasswords(new File(path), PasswordRepository.getRepositoryDirectory(requireContext()), getSortOrder()));
     }
 
     @Override
@@ -65,19 +66,19 @@ public class PasswordFragment extends Fragment {
         View view = inflater.inflate(R.layout.password_recycler_view, container, false);
 
         // use a linear layout manager
-        RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getActivity());
+        RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(requireContext());
 
         recyclerView = view.findViewById(R.id.pass_recycler);
         recyclerView.setLayoutManager(mLayoutManager);
 
         // use divider
-        recyclerView.addItemDecoration(new DividerItemDecoration(getActivity(), R.drawable.divider));
+        recyclerView.addItemDecoration(new DividerItemDecoration(requireContext(), DividerItemDecoration.VERTICAL));
 
         // Set the adapter
         recyclerView.setAdapter(recyclerAdapter);
 
         final FloatingActionButton fab = view.findViewById(R.id.fab);
-        fab.setOnClickListener(v -> ((PasswordStore) getActivity()).createPassword());
+        fab.setOnClickListener(v -> ((PasswordStore) requireActivity()).createPassword());
 
         registerForContextMenu(recyclerView);
         return view;
@@ -101,18 +102,17 @@ public class PasswordFragment extends Fragment {
                     recyclerAdapter.clear();
                     recyclerAdapter.addAll(PasswordRepository.getPasswords(item.getFile(), PasswordRepository.getRepositoryDirectory(context), getSortOrder()));
 
-                    ((AppCompatActivity) getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(true);
+                    ((AppCompatActivity) requireActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(true);
                 } else {
                     if (getArguments().getBoolean("matchWith", false)) {
-                        ((PasswordStore) getActivity()).matchPasswordWithApp(item);
+                        ((PasswordStore) requireActivity()).matchPasswordWithApp(item);
                     } else {
-                        ((PasswordStore) getActivity()).decryptPassword(item);
+                        ((PasswordStore) requireActivity()).decryptPassword(item);
                     }
                 }
             };
         } catch (ClassCastException e) {
-            throw new ClassCastException(context.toString()
-                    + " must implement OnFragmentInteractionListener");
+            throw new ClassCastException(context + " must implement OnFragmentInteractionListener");
         }
     }
 
@@ -124,9 +124,9 @@ public class PasswordFragment extends Fragment {
         pathStack.clear();
         scrollPosition.clear();
         recyclerAdapter.clear();
-        recyclerAdapter.addAll(PasswordRepository.getPasswords(PasswordRepository.getRepositoryDirectory(getActivity()), getSortOrder()));
+        recyclerAdapter.addAll(PasswordRepository.getPasswords(PasswordRepository.getRepositoryDirectory(requireContext()), getSortOrder()));
 
-        ((AppCompatActivity) getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(false);
+        ((AppCompatActivity) requireActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(false);
     }
 
     /**
@@ -135,8 +135,8 @@ public class PasswordFragment extends Fragment {
     public void refreshAdapter() {
         recyclerAdapter.clear();
         recyclerAdapter.addAll(pathStack.isEmpty() ?
-                PasswordRepository.getPasswords(PasswordRepository.getRepositoryDirectory(getActivity()), getSortOrder()) :
-                PasswordRepository.getPasswords(pathStack.peek(), PasswordRepository.getRepositoryDirectory(getActivity()), getSortOrder()));
+                PasswordRepository.getPasswords(PasswordRepository.getRepositoryDirectory(requireContext()), getSortOrder()) :
+                PasswordRepository.getPasswords(pathStack.peek(), PasswordRepository.getRepositoryDirectory(requireContext()), getSortOrder()));
     }
 
     /**
@@ -163,8 +163,8 @@ public class PasswordFragment extends Fragment {
     private void recursiveFilter(String filter, File dir) {
         // on the root the pathStack is empty
         ArrayList<PasswordItem> passwordItems = dir == null ?
-                PasswordRepository.getPasswords(PasswordRepository.getRepositoryDirectory(getActivity()), getSortOrder()) :
-                PasswordRepository.getPasswords(dir, PasswordRepository.getRepositoryDirectory(getActivity()), getSortOrder());
+                PasswordRepository.getPasswords(PasswordRepository.getRepositoryDirectory(requireContext()), getSortOrder()) :
+                PasswordRepository.getPasswords(dir, PasswordRepository.getRepositoryDirectory(requireContext()), getSortOrder());
 
         boolean rec = settings.getBoolean("filter_recursively", true);
         for (PasswordItem item : passwordItems) {
@@ -201,7 +201,7 @@ public class PasswordFragment extends Fragment {
      */
     public File getCurrentDir() {
         if (pathStack.isEmpty())
-            return PasswordRepository.getRepositoryDirectory(getActivity().getApplicationContext());
+            return PasswordRepository.getRepositoryDirectory(requireContext());
         else
             return pathStack.peek();
     }
diff --git a/app/src/main/java/com/zeapo/pwdstore/PasswordGeneratorDialogFragment.java b/app/src/main/java/com/zeapo/pwdstore/PasswordGeneratorDialogFragment.java
index 698ec495..0f2d22cf 100644
--- a/app/src/main/java/com/zeapo/pwdstore/PasswordGeneratorDialogFragment.java
+++ b/app/src/main/java/com/zeapo/pwdstore/PasswordGeneratorDialogFragment.java
@@ -37,8 +37,8 @@ public class PasswordGeneratorDialogFragment extends DialogFragment {
     @SuppressLint("SetTextI18n")
     @Override
     public Dialog onCreateDialog(Bundle savedInstanceState) {
-        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
-        final Activity callingActivity = getActivity();
+        AlertDialog.Builder builder = new AlertDialog.Builder(requireActivity());
+        final Activity callingActivity = requireActivity();
         LayoutInflater inflater = callingActivity.getLayoutInflater();
         @SuppressLint("InflateParams") final View view = inflater.inflate(R.layout.fragment_pwgen, null);
         Typeface monoTypeface = Typeface.createFromAsset(callingActivity.getAssets(), "fonts/sourcecodepro.ttf");
@@ -46,7 +46,7 @@ public class PasswordGeneratorDialogFragment extends DialogFragment {
         builder.setView(view);
 
         SharedPreferences prefs
-                = getActivity().getApplicationContext().getSharedPreferences("PasswordGenerator", Context.MODE_PRIVATE);
+                = requireActivity().getApplicationContext().getSharedPreferences("PasswordGenerator", Context.MODE_PRIVATE);
 
         CheckBox checkBox = view.findViewById(R.id.numerals);
         checkBox.setChecked(!prefs.getBoolean("0", false));
@@ -87,9 +87,9 @@ public class PasswordGeneratorDialogFragment extends DialogFragment {
         ad.setOnShowListener(dialog -> {
             setPreferences();
             try {
-                passwordText.setText(PasswordGenerator.INSTANCE.generate(getActivity().getApplicationContext()).get(0));
+                passwordText.setText(PasswordGenerator.generate(requireActivity().getApplicationContext()).get(0));
             } catch (PasswordGenerator.PasswordGeneratorExeption e) {
-                Toast.makeText(getActivity(), e.getMessage(), Toast.LENGTH_SHORT).show();
+                Toast.makeText(requireActivity(), e.getMessage(), Toast.LENGTH_SHORT).show();
                 passwordText.setText("");
             }
 
@@ -97,9 +97,9 @@ public class PasswordGeneratorDialogFragment extends DialogFragment {
             b.setOnClickListener(v -> {
                 setPreferences();
                 try {
-                    passwordText.setText(PasswordGenerator.INSTANCE.generate(callingActivity.getApplicationContext()).get(0));
+                    passwordText.setText(PasswordGenerator.generate(callingActivity.getApplicationContext()).get(0));
                 } catch (PasswordGenerator.PasswordGeneratorExeption e) {
-                    Toast.makeText(getActivity(), e.getMessage(), Toast.LENGTH_SHORT).show();
+                    Toast.makeText(requireActivity(), e.getMessage(), Toast.LENGTH_SHORT).show();
                     passwordText.setText("");
                 }
             });
@@ -131,9 +131,9 @@ public class PasswordGeneratorDialogFragment extends DialogFragment {
         EditText editText = getDialog().findViewById(R.id.lengthNumber);
         try {
             int length = Integer.valueOf(editText.getText().toString());
-            PasswordGenerator.INSTANCE.setPrefs(getActivity().getApplicationContext(), preferences, length);
+            PasswordGenerator.setPrefs(requireActivity().getApplicationContext(), preferences, length);
         } catch (NumberFormatException e) {
-            PasswordGenerator.INSTANCE.setPrefs(getActivity().getApplicationContext(), preferences);
+            PasswordGenerator.setPrefs(requireActivity().getApplicationContext(), preferences);
         }
     }
 }
diff --git a/app/src/main/java/com/zeapo/pwdstore/SelectFolderFragment.java b/app/src/main/java/com/zeapo/pwdstore/SelectFolderFragment.java
index 1fe79a2a..31fd57a1 100644
--- a/app/src/main/java/com/zeapo/pwdstore/SelectFolderFragment.java
+++ b/app/src/main/java/com/zeapo/pwdstore/SelectFolderFragment.java
@@ -9,6 +9,7 @@ import android.view.ViewGroup;
 import androidx.annotation.NonNull;
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.fragment.app.Fragment;
+import androidx.recyclerview.widget.DividerItemDecoration;
 import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
 import com.google.android.material.floatingactionbutton.FloatingActionButton;
@@ -46,8 +47,8 @@ public class SelectFolderFragment extends Fragment {
         String path = getArguments().getString("Path");
 
         pathStack = new Stack<>();
-        recyclerAdapter = new FolderRecyclerAdapter((SelectFolderActivity) getActivity(), mListener,
-                PasswordRepository.getPasswords(new File(path), PasswordRepository.getRepositoryDirectory(getActivity()), getSortOrder()));
+        recyclerAdapter = new FolderRecyclerAdapter((SelectFolderActivity) requireActivity(), mListener,
+                PasswordRepository.getPasswords(new File(path), PasswordRepository.getRepositoryDirectory(requireActivity()), getSortOrder()));
     }
 
     @Override
@@ -57,10 +58,10 @@ public class SelectFolderFragment extends Fragment {
 
         // use a linear layout manager
         recyclerView = view.findViewById(R.id.pass_recycler);
-        recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
+        recyclerView.setLayoutManager(new LinearLayoutManager(requireContext()));
 
         // use divider
-        recyclerView.addItemDecoration(new DividerItemDecoration(getActivity(), R.drawable.divider));
+        recyclerView.addItemDecoration(new DividerItemDecoration(requireContext(), DividerItemDecoration.VERTICAL));
 
         // Set the adapter
         recyclerView.setAdapter(recyclerAdapter);
@@ -84,7 +85,7 @@ public class SelectFolderFragment extends Fragment {
                     recyclerAdapter.clear();
                     recyclerAdapter.addAll(PasswordRepository.getPasswords(item.getFile(), PasswordRepository.getRepositoryDirectory(context), getSortOrder()));
 
-                    ((AppCompatActivity) getActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(true);
+                    ((AppCompatActivity) requireActivity()).getSupportActionBar().setDisplayHomeAsUpEnabled(true);
                 }
             };
         } catch (ClassCastException e) {
@@ -100,13 +101,13 @@ public class SelectFolderFragment extends Fragment {
      */
     public File getCurrentDir() {
         if (pathStack.isEmpty())
-            return PasswordRepository.getRepositoryDirectory(getActivity().getApplicationContext());
+            return PasswordRepository.getRepositoryDirectory(requireContext());
         else
             return pathStack.peek();
     }
 
     private PasswordRepository.PasswordSortOrder getSortOrder() {
-        return PasswordRepository.PasswordSortOrder.getSortOrder(PreferenceManager.getDefaultSharedPreferences(getActivity()));
+        return PasswordRepository.PasswordSortOrder.getSortOrder(PreferenceManager.getDefaultSharedPreferences(requireContext()));
     }
 
     public interface OnFragmentInteractionListener {
diff --git a/app/src/main/java/com/zeapo/pwdstore/pwgen/PasswordGenerator.kt b/app/src/main/java/com/zeapo/pwdstore/pwgen/PasswordGenerator.kt
index 6132d2dc..dcb2c199 100644
--- a/app/src/main/java/com/zeapo/pwdstore/pwgen/PasswordGenerator.kt
+++ b/app/src/main/java/com/zeapo/pwdstore/pwgen/PasswordGenerator.kt
@@ -47,6 +47,7 @@ object PasswordGenerator {
      * @return `false` if a numerical options is invalid,
      * `true` otherwise
      */
+    @JvmStatic
     fun setPrefs(ctx: Context, argv: ArrayList<String>, vararg numArgv: Int): Boolean {
         val prefs = ctx.getSharedPreferences("PasswordGenerator", Context.MODE_PRIVATE)
         val editor = prefs.edit()
@@ -81,7 +82,7 @@ object PasswordGenerator {
      * preferences file 'PasswordGenerator'
      * @return list of generated passwords
      */
-    @Throws(PasswordGenerator.PasswordGeneratorExeption::class)
+    @JvmStatic @Throws(PasswordGenerator.PasswordGeneratorExeption::class)
     fun generate(ctx: Context): ArrayList<String> {
         val prefs = ctx.getSharedPreferences("PasswordGenerator", Context.MODE_PRIVATE)
 
@@ -140,6 +141,6 @@ object PasswordGenerator {
         return passwords
     }
 
-    public class PasswordGeneratorExeption(string: String) : Exception(string)
+    class PasswordGeneratorExeption(string: String) : Exception(string)
 }