updated the gradle and dependencies.

app/build.gradle

@@ -1,15 +1,15 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 25
-    buildToolsVersion "25.0.2"
+    compileSdkVersion 28
+    buildToolsVersion "28.0.2"
     defaultConfig {
         applicationId "com.example.android.shushme"
-        minSdkVersion 16
-        targetSdkVersion 25
+        minSdkVersion 24
+        targetSdkVersion 28
         versionCode 1
         versionName "1.0"
-        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }
     buildTypes {
         release {
@@ -20,13 +20,13 @@ android {
 }
 
 dependencies {
-    compile fileTree(dir: 'libs', include: ['*.jar'])
-    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
+    androidTestCompile('androidx.test.espresso:espresso-core:3.1.0', {
         exclude group: 'com.android.support', module: 'support-annotations'
     })
-    compile 'com.android.support:appcompat-v7:25.1.0'
-    compile 'com.android.support:recyclerview-v7:25.0.1'
-    compile 'com.google.android.gms:play-services-places:9.8.0'
-    compile 'com.google.android.gms:play-services-location:9.8.0'
-    testCompile 'junit:junit:4.12'
+    implementation 'androidx.appcompat:appcompat:1.1.0'
+    implementation 'androidx.recyclerview:recyclerview:1.1.0'
+    implementation 'com.google.android.gms:play-services-places:17.0.0'
+    implementation 'com.google.android.gms:play-services-location:17.0.0'
+    testImplementation 'junit:junit:4.12'
 }

app/src/main/AndroidManifest.xml

@@ -11,7 +11,7 @@
 
         <meta-data
             android:name="com.google.android.geo.API_KEY"
-            android:value="insert-your-api-key-here" />
+            android:value="AIzaSyBmQz72bfbRLOX4OC1ePpJfGmanMjiZzv0" />
 
         <activity android:name="com.example.android.shushme.MainActivity">
             <intent-filter>

app/src/main/java/com/example/android/shushme/GeofenceBroadcastReceiver.java

@@ -16,11 +16,21 @@
 * limitations under the License.
 */
 
+import android.app.NotificationManager;
+import android.app.PendingIntent;
+import android.app.TaskStackBuilder;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
+import android.graphics.BitmapFactory;
+import android.media.AudioManager;
+import androidx.core.app.NotificationCompat;
+
 import android.util.Log;
 
+import com.google.android.gms.location.Geofence;
+import com.google.android.gms.location.GeofencingEvent;
+
 public class GeofenceBroadcastReceiver extends BroadcastReceiver {
 
     public static final String TAG = GeofenceBroadcastReceiver.class.getSimpleName();

app/src/main/java/com/example/android/shushme/Geofencing.java

@@ -19,7 +19,7 @@
 import android.app.PendingIntent;
 import android.content.Context;
 import android.content.Intent;
-import android.support.annotation.NonNull;
+import androidx.annotation.NonNull;
 import android.util.Log;
 
 import com.google.android.gms.common.api.GoogleApiClient;

app/src/main/java/com/example/android/shushme/MainActivity.java

@@ -24,12 +24,12 @@
 import android.database.Cursor;
 import android.net.Uri;
 import android.os.Bundle;
-import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
-import android.support.v4.app.ActivityCompat;
-import android.support.v7.app.AppCompatActivity;
-import android.support.v7.widget.LinearLayoutManager;
-import android.support.v7.widget.RecyclerView;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.core.app.ActivityCompat;
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.recyclerview.widget.LinearLayoutManager;
+import androidx.recyclerview.widget.RecyclerView;
 import android.util.Log;
 import android.view.View;
 import android.widget.CheckBox;
@@ -211,6 +211,7 @@ public void onAddPlaceButtonClicked(View view) {
      * @param data        The Intent that carries the result data.
      */
     protected void onActivityResult(int requestCode, int resultCode, Intent data) {
+        super.onActivityResult(requestCode, resultCode, data);
         if (requestCode == PLACE_PICKER_REQUEST && resultCode == RESULT_OK) {
             Place place = PlacePicker.getPlace(this, data);
             if (place == null) {

app/src/main/java/com/example/android/shushme/PlaceListAdapter.java

@@ -17,7 +17,7 @@
 */
 
 import android.content.Context;
-import android.support.v7.widget.RecyclerView;
+import androidx.recyclerview.widget.RecyclerView;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;

app/src/main/java/com/example/android/shushme/provider/PlaceContentProvider.java

@@ -24,7 +24,7 @@
 import android.database.Cursor;
 import android.database.sqlite.SQLiteDatabase;
 import android.net.Uri;
-import android.support.annotation.NonNull;
+import androidx.annotation.NonNull;
 
 import static com.example.android.shushme.provider.PlaceContract.PlaceEntry;
 

app/src/main/res/layout/activity_main.xml

@@ -156,7 +156,7 @@
             android:layout_marginTop="4dp"
             android:background="@color/colorPrimary" />
 
-        <android.support.v7.widget.RecyclerView
+        <androidx.recyclerview.widget.RecyclerView
             android:id="@+id/places_list_recycler_view"
             android:layout_width="match_parent"
             android:layout_height="wrap_content" />

build.gradle

@@ -3,9 +3,10 @@
 buildscript {
     repositories {
         jcenter()
+        google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.2.3'
+        classpath 'com.android.tools.build:gradle:3.6.3'
 
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
@@ -15,6 +16,11 @@ buildscript {
 allprojects {
     repositories {
         jcenter()
+        maven {
+            url "https://maven.google.com"
+        }
+        google()
+
     }
 }
 

gradle.properties

@@ -9,6 +9,8 @@
 
 # Specifies the JVM arguments used for the daemon process.
 # The setting is particularly useful for tweaking memory settings.
+android.enableJetifier=true
+android.useAndroidX=true
 org.gradle.jvmargs=-Xmx1536m
 
 # When configured, Gradle will run in incubating parallel mode.

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Mon Dec 28 10:00:20 PST 2015
+#Wed Apr 22 02:37:37 CAT 2020
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.14.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.4-all.zip