Android Studio - Cannot find symbol class - android-studio

Question

When I run my app, Android Studio notifies me some error in Gradle Build.
Could you help me understand how to fix this problem?
MapsActivity
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
private GoogleMap mMap;
DatabaseHelper myDb;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
addMarkers();
}
#Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
// Add a marker in Sydney and move the camera
LatLng sydney = new LatLng(-34, 151);
LatLng ruvo = new LatLng(-45, 123);
mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
mMap.addMarker(new MarkerOptions().position(ruvo).title("Marker in Sydney"));
mMap.moveCamera(CameraUpdateFactory.newLatLng(ruvo));
}
public void onSearch(View view) {
EditText textCity = (EditText) findViewById(R.id.textCity);
String location = textCity.getText().toString();
List<android.location.Address> addressList = null;
if (location != null) {
Geocoder geocoder = new Geocoder(this);
try {
addressList = geocoder.getFromLocationName(location, 1);
} catch (IOException e) {
e.printStackTrace();
}
android.location.Address address = addressList.get(0);
LatLng latLng = new LatLng(address.getLatitude(), address.getLongitude());
mMap.addMarker(new MarkerOptions().position(latLng).title("Marker pointed"));
mMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
} else {
textCity.setHint("Enter a valid city");
//textCity.setTextColor();
}
}
public void addMarkers() {
ArrayList<OverlayItem> items = new ArrayList<OverlayItem>();
Cursor database = myDb.display();
if (database.getCount()== 0) {
Toast.makeText(this, "Nothing to found", Toast.LENGTH_LONG).show();
return;
}
database.moveToFirst();
do {
int latitude = (int) (database.getDouble(database.getColumnIndex("LAT")) * 1E6);
int longitude = (int) (database.getDouble(database.getColumnIndex("LONG")) * 1E6);
items.add(new OverlayItem(new GeoPoint(latitude, longitude)));
} while (database.moveToNext());
}
}
build.gradle
apply plugin: 'com.android.application'
android {
compileSdkVersion 23
buildToolsVersion "23.0.3"
defaultConfig {
applicationId "com.example.android.sqlite"
minSdkVersion 16
targetSdkVersion 23
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:23.3.0'
compile 'com.google.android.gms:play-services:9.2.0'
}
Error messages:
Error:(82, 19) error: cannot find symbol class OverlayItem
Error:(82, 54) error: cannot find symbol class OverlayItem
Error:(92, 31) error: cannot find symbol class OverlayItem
Error:(92, 47) error: cannot find symbol class GeoPoint
Error:Execution failed for task ':app:compileDebugJavaWithJavac'.
Compilation failed; see the compiler error output for details.`