Add target SDK

app/build.gradle

@@ -1,15 +1,15 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 29
+    compileSdkVersion 30
 
     defaultConfig {
         applicationId 'org.traccar.client'
         buildConfigField 'boolean', 'HIDDEN_APP', 'false'
         minSdkVersion 16
-        targetSdkVersion 29
-        versionCode 66
-        versionName '6.5'
+        targetSdkVersion 30
+        versionCode 67
+        versionName '6.6'
         multiDexEnabled true
     }
 

app/src/main/java/org/traccar/client/MainActivity.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 Anton Tananaev (anton@traccar.org)
+ * Copyright 2017 - 2020 Anton Tananaev (anton@traccar.org)
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,9 +24,7 @@ public class MainActivity extends AppCompatActivity {
     @Override
     protected void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-        if (savedInstanceState == null) {
-            getSupportFragmentManager().beginTransaction().replace(android.R.id.content, new MainFragment()).commit();
-        }
+        setContentView(R.layout.main);
     }
 
 }

app/src/main/java/org/traccar/client/MainFragment.java

@@ -47,6 +47,8 @@ import androidx.preference.PreferenceFragmentCompat;
 import androidx.preference.PreferenceManager;
 import androidx.preference.TwoStatePreference;
 
+import com.google.android.material.snackbar.Snackbar;
+
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Random;
@@ -69,6 +71,7 @@ public class MainFragment extends PreferenceFragmentCompat implements OnSharedPr
     public static final String KEY_WAKELOCK = "wakelock";
 
     private static final int PERMISSIONS_REQUEST_LOCATION = 2;
+    private static final String KEY_DISCLOSURE_SHOWN = "disclosureShown";
 
     private SharedPreferences sharedPreferences;
 
@@ -77,6 +80,7 @@ public class MainFragment extends PreferenceFragmentCompat implements OnSharedPr
 
     @Override
     public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
+
         if (BuildConfig.HIDDEN_APP && Build.VERSION.SDK_INT < Build.VERSION_CODES.Q) {
             removeLauncherIcon();
         }
@@ -191,6 +195,17 @@ public class MainFragment extends PreferenceFragmentCompat implements OnSharedPr
     public void onResume() {
         super.onResume();
         sharedPreferences.registerOnSharedPreferenceChangeListener(this);
+
+        if (!sharedPreferences.getBoolean(KEY_DISCLOSURE_SHOWN, false)) {
+            Snackbar.make(getView(), R.string.disclosure_location, Snackbar.LENGTH_INDEFINITE)
+                    .addCallback(new Snackbar.Callback() {
+                        @Override
+                        public void onDismissed(Snackbar transientBottomBar, int event) {
+                            sharedPreferences.edit().putBoolean(KEY_DISCLOSURE_SHOWN, true).apply();
+                        }
+                    })
+                    .show();
+        }
     }
 
     @Override

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

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.coordinatorlayout.widget.CoordinatorLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <androidx.fragment.app.FragmentContainerView
+        android:id="@+id/fragment"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:name="org.traccar.client.MainFragment" />
+
+</androidx.coordinatorlayout.widget.CoordinatorLayout>

app/src/main/res/values/strings.xml

@@ -46,4 +46,5 @@
   <string name="hidden_app_name">Device Settings</string>
   <string name="hidden_alert">The app has been hidden. To open it again please dial 8722227 (TRACCAR).</string>
   <string name="error_msg_invalid_url">Please enter a valid http:// or https:// URL</string>
+  <string name="disclosure_location">This app collects location data to enable live tracking even when the app is closed or not in use.</string>
 </resources>

build.gradle

@@ -4,9 +4,9 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:4.0.2'
-        classpath 'com.google.gms:google-services:4.3.3'
-        classpath 'com.google.firebase:firebase-crashlytics-gradle:2.3.0'
+        classpath 'com.android.tools.build:gradle:4.2.0-beta01'
+        classpath 'com.google.gms:google-services:4.3.4'
+        classpath 'com.google.firebase:firebase-crashlytics-gradle:2.4.1'
     }
 }
 

gradle/wrapper/gradle-wrapper.properties

@@ -2,4 +2,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.1.1-all.zip
+distributionUrl=https://services.gradle.org/distributions/gradle-6.7-bin.zip