Fixed lint warnings.

Android/app/src/main/java/com/example/samplestickerapp/AddStickerPackActivity.java

@@ -23,8 +23,8 @@ import androidx.appcompat.app.AlertDialog;
 import androidx.fragment.app.DialogFragment;
 
 public abstract class AddStickerPackActivity extends BaseActivity {
-    public static final int ADD_PACK = 200;
-    public static final String TAG = "AddStickerPackActivity";
+    private static final int ADD_PACK = 200;
+    private static final String TAG = "AddStickerPackActivity";
 
     protected void addStickerPackToWhatsApp(String identifier, String stickerPackName) {
         try {

Android/app/src/main/java/com/example/samplestickerapp/Sticker.java

@@ -14,8 +14,8 @@ import android.os.Parcelable;
 import java.util.List;
 
 class Sticker implements Parcelable {
-    String imageFileName;
-    List<String> emojis;
+    final String imageFileName;
+    final List<String> emojis;
     long size;
 
     Sticker(String imageFileName, List<String> emojis) {

Android/app/src/main/java/com/example/samplestickerapp/StickerContentProvider.java

@@ -51,15 +51,15 @@ public class StickerContentProvider extends ContentProvider {
 
     public static final String STICKER_FILE_NAME_IN_QUERY = "sticker_file_name";
     public static final String STICKER_FILE_EMOJI_IN_QUERY = "sticker_emoji";
-    public static final String CONTENT_FILE_NAME = "contents.json";
+    private static final String CONTENT_FILE_NAME = "contents.json";
 
-    public static Uri AUTHORITY_URI = new Uri.Builder().scheme(ContentResolver.SCHEME_CONTENT).authority(BuildConfig.CONTENT_PROVIDER_AUTHORITY).appendPath(StickerContentProvider.METADATA).build();
+    public static final Uri AUTHORITY_URI = new Uri.Builder().scheme(ContentResolver.SCHEME_CONTENT).authority(BuildConfig.CONTENT_PROVIDER_AUTHORITY).appendPath(StickerContentProvider.METADATA).build();
 
     /**
      * Do not change the values in the UriMatcher because otherwise, WhatsApp will not be able to fetch the stickers from the ContentProvider.
      */
     private static final UriMatcher MATCHER = new UriMatcher(UriMatcher.NO_MATCH);
-    static final String METADATA = "metadata";
+    private static final String METADATA = "metadata";
     private static final int METADATA_CODE = 1;
 
     private static final int METADATA_CODE_FOR_SINGLE_PACK = 2;
@@ -153,7 +153,7 @@ public class StickerContentProvider extends ContentProvider {
         }
     }
 
-    public List<StickerPack> getStickerPackList() {
+    private List<StickerPack> getStickerPackList() {
         if (stickerPackList == null) {
             readContentFile(Objects.requireNonNull(getContext()));
         }

Android/app/src/main/java/com/example/samplestickerapp/StickerPack.java

@@ -14,10 +14,10 @@ import android.os.Parcelable;
 import java.util.List;
 
 class StickerPack implements Parcelable {
-    String identifier;
-    String name;
-    String publisher;
-    String trayImageFile;
+    final String identifier;
+    final String name;
+    final String publisher;
+    final String trayImageFile;
     final String publisherEmail;
     final String publisherWebsite;
     final String privacyPolicyWebsite;
@@ -52,7 +52,7 @@ class StickerPack implements Parcelable {
         return isWhitelisted;
     }
 
-    protected StickerPack(Parcel in) {
+    private StickerPack(Parcel in) {
         identifier = in.readString();
         name = in.readString();
         publisher = in.readString();

Android/app/src/main/java/com/example/samplestickerapp/StickerPackDetailsActivity.java

@@ -190,7 +190,6 @@ public class StickerPackDetailsActivity extends AddStickerPackActivity {
         protected final Boolean doInBackground(StickerPack... stickerPacks) {
             StickerPack stickerPack = stickerPacks[0];
             final StickerPackDetailsActivity stickerPackDetailsActivity = stickerPackDetailsActivityWeakReference.get();
-            //noinspection SimplifiableIfStatement
             if (stickerPackDetailsActivity == null) {
                 return false;
             }

Android/app/src/main/java/com/example/samplestickerapp/StickerPackListItemViewHolder.java

@@ -17,12 +17,12 @@ import androidx.recyclerview.widget.RecyclerView;
 
 class StickerPackListItemViewHolder extends RecyclerView.ViewHolder {
 
-    View container;
-    TextView titleView;
-    TextView publisherView;
-    TextView filesizeView;
-    ImageView addButton;
-    LinearLayout imageRowView;
+    final View container;
+    final TextView titleView;
+    final TextView publisherView;
+    final TextView filesizeView;
+    final ImageView addButton;
+    final LinearLayout imageRowView;
 
     StickerPackListItemViewHolder(final View itemView) {
         super(itemView);

Android/app/src/main/java/com/example/samplestickerapp/StickerPreviewAdapter.java

@@ -18,11 +18,11 @@ import androidx.recyclerview.widget.RecyclerView;
 public class StickerPreviewAdapter extends RecyclerView.Adapter<StickerPreviewViewHolder> {
 
     @NonNull
-    private StickerPack stickerPack;
+    private final StickerPack stickerPack;
 
     private final int cellSize;
-    private int cellLimit;
-    private int cellPadding;
+    private final int cellLimit;
+    private final int cellPadding;
     private final int errorResource;
 
     private final LayoutInflater layoutInflater;

Android/app/src/main/java/com/example/samplestickerapp/WhitelistCheck.java

@@ -18,16 +18,15 @@ import android.net.Uri;
 
 import androidx.annotation.NonNull;
 
-@SuppressWarnings("FieldCanBeLocal")
 class WhitelistCheck {
     private static final String AUTHORITY_QUERY_PARAM = "authority";
     private static final String IDENTIFIER_QUERY_PARAM = "identifier";
-    private static String STICKER_APP_AUTHORITY = BuildConfig.CONTENT_PROVIDER_AUTHORITY;
+    private static final String STICKER_APP_AUTHORITY = BuildConfig.CONTENT_PROVIDER_AUTHORITY;
     static final String CONSUMER_WHATSAPP_PACKAGE_NAME = "com.whatsapp";
     static final String SMB_WHATSAPP_PACKAGE_NAME = "com.whatsapp.w4b";
-    private static String CONTENT_PROVIDER = ".provider.sticker_whitelist_check";
-    private static String QUERY_PATH = "is_whitelisted";
-    private static String QUERY_RESULT_COLUMN_NAME = "result";
+    private static final String CONTENT_PROVIDER = ".provider.sticker_whitelist_check";
+    private static final String QUERY_PATH = "is_whitelisted";
+    private static final String QUERY_RESULT_COLUMN_NAME = "result";
 
     static boolean isWhitelisted(@NonNull Context context, @NonNull String identifier) {
         try {
@@ -65,7 +64,7 @@ class WhitelistCheck {
         return false;
     }
 
-    public static boolean isPackageInstalled(String packageName, PackageManager packageManager) {
+    static boolean isPackageInstalled(String packageName, PackageManager packageManager) {
         try {
             final ApplicationInfo applicationInfo = packageManager.getApplicationInfo(packageName, 0);
             //noinspection SimplifiableIfStatement