gradle dependencies updated and fixed warnings

app/build.gradle

@@ -1,11 +1,11 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 26
+    compileSdkVersion 28
     defaultConfig {
         applicationId "androidbuffer.com.readcontactdemo"
         minSdkVersion 15
-        targetSdkVersion 26
+        targetSdkVersion 28
         versionCode 1
         versionName "1.0"
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
@@ -20,9 +20,8 @@ android {
 
 dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
-    implementation 'com.android.support:appcompat-v7:26.1.0'
-    implementation 'com.android.support.constraint:constraint-layout:1.1.2'
+    implementation 'com.android.support:appcompat-v7:28.0.0-rc01'
+    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
     testImplementation 'junit:junit:4.12'
-    compile 'com.android.support:recyclerview-v7:26.1.0+'
-    compile 'com.android.support:design:26.1.0+'
+    implementation 'com.android.support:design:28.0.0-rc01'
 }

app/src/main/AndroidManifest.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
     package="androidbuffer.com.readcontactdemo">
 
     <uses-permission android:name="android.permission.INTERNET"/>
@@ -12,11 +13,12 @@
         android:label="@string/app_name"
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
-        android:theme="@style/AppTheme">
+        android:theme="@style/AppTheme"
+        android:fullBackupContent="true"
+        tools:ignore="GoogleAppIndexingWarning">
         <activity android:name=".MainActivity">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
-
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>

app/src/main/java/androidbuffer/com/readcontactdemo/ContactAdapter.java

@@ -1,5 +1,6 @@
 package androidbuffer.com.readcontactdemo;
 
+import android.support.annotation.NonNull;
 import android.support.v7.widget.RecyclerView;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -16,18 +17,19 @@ public class ContactAdapter extends RecyclerView.Adapter<ContactAdapter.MyViewHo
 
     private List<ContactModel> contactModelList;
 
-    public ContactAdapter(List<ContactModel> contactModelList) {
+    ContactAdapter(List<ContactModel> contactModelList) {
         this.contactModelList = contactModelList;
     }
 
+    @NonNull
     @Override
-    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
+    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
         View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_contact, parent, false);
         return new MyViewHolder(view);
     }
 
     @Override
-    public void onBindViewHolder(MyViewHolder holder, int position) {
+    public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
         ContactModel model = contactModelList.get(position);
         if (model != null){
             if (model.getName() != null){
@@ -49,11 +51,10 @@ public int getItemCount() {
         return contactModelList.size();
     }
 
-    public class MyViewHolder extends RecyclerView.ViewHolder {
-
+    class MyViewHolder extends RecyclerView.ViewHolder {
         TextView name, number;
 
-        public MyViewHolder(View itemView) {
+        MyViewHolder(View itemView) {
             super(itemView);
 
             name = itemView.findViewById(R.id.tvName);

app/src/main/java/androidbuffer/com/readcontactdemo/MainActivity.java

@@ -60,21 +60,22 @@ private void getContactInfo(){
         ContentResolver contentResolver = getContentResolver();
         Cursor cursor = contentResolver.query(CONTENT_URI,null,null,null,DISPLAY_NAME);
 
-        if (cursor.getCount() > 0){
-            while (cursor.moveToNext()){
+        if (cursor != null && cursor.getCount() > 0) {
+            while (cursor.moveToNext()) {
                 String CONTACT_ID = cursor.getString(cursor.getColumnIndex(ID));
                 String name = cursor.getString(cursor.getColumnIndex(DISPLAY_NAME));
 
                 int hasPhoneNumber = cursor.getInt(cursor.getColumnIndex(HAS_PHONE_NUMBER));
                 ContactModel contactModel = new ContactModel();
-                if (hasPhoneNumber > 0){
+                if (hasPhoneNumber > 0) {
                     contactModel.setName(name);
 
-                    Cursor phoneCursor = contentResolver.query(PHONE_URI, new String[]{NUMBER},PHONE_ID+" = ?",new String[]{CONTACT_ID},null);
+                    Cursor phoneCursor = contentResolver.query(PHONE_URI, new String[]{NUMBER}, PHONE_ID + " = ?", new String[]{CONTACT_ID}, null);
                     List<String> contactList = new ArrayList<>();
+                    assert phoneCursor != null;
                     phoneCursor.moveToFirst();
-                    while (!phoneCursor.isAfterLast()){
-                        String phoneNumber = phoneCursor.getString(phoneCursor.getColumnIndex(NUMBER)).replace(" ","");
+                    while (!phoneCursor.isAfterLast()) {
+                        String phoneNumber = phoneCursor.getString(phoneCursor.getColumnIndex(NUMBER)).replace(" ", "");
                         contactList.add(phoneNumber);
                         phoneCursor.moveToNext();
                     }
@@ -84,6 +85,7 @@ private void getContactInfo(){
                 }
             }
             contactAdapter.notifyDataSetChanged();
+            cursor.close();
         }
     }
 

build.gradle

@@ -7,7 +7,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.0.1'
+        classpath 'com.android.tools.build:gradle:3.1.4'
 
 
         // NOTE: Do not place your application dependencies here; they belong

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Fri Jul 06 11:41:45 IST 2018
+#Mon Sep 10 14:01:04 IST 2018
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-all.zip