Develop Reference

SupportMapFragment set google maps Zoom level

how can i set the zoom level of a SupportMapFragment ?
I tried some answers I found in similar questions, like this one answered buy a guy named Rob who proposed:
LatLng currentLocation = mService.getCurrentLocation();
CameraPosition cameraPosition = new CameraPosition.Builder()
.target(currentLocation) // Sets the center of the map to the current location of the user
.zoom(17) // Sets the zoom
.bearing(90) // Sets the orientation of the camera to east
.tilt(30) // Sets the tilt of the camera to 30 degrees
.build(); // Creates a CameraPosition from the builder
mGoogleMap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));
But this solution didn't work. So, how can I set the Zoom level knowing that I use a SupportMapFragment.

if your current location is not null then try this code it will work
LatLng currentLocation = mService.getCurrentLocation();
CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(currentLocation , 16);
mMap.addMarker(new MarkerOptions().position(location).title(""));
mMap.moveCamera(CameraUpdateFactory.newLatLng(currentLocation ));
mMap.animateCamera(cameraUpdate)

Marker currentMarker;
MarkerOptions marker = new MarkerOptions().position(new
LatLng(Double.
parseDouble(lat),Double.parseDouble(lon))).title(title);
marker.icon(BitmapDescriptorFactory.fromResource(R.drawable.ic_schoolbus));
currentMarker = map.addMarker(marker);
currentMarker.showInfoWindow();
currentMarker.setIcon(BitmapDescriptorFactory.fromResource(R.drawable.ic_schoolbus));
map.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(Double.parseDouble(lat),Double.parseDouble(lon)), 15));

Show route direction in Google Maps

googleMap = ((SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map)).getMap();
googleMap.addMarker(new MarkerOptions()
.position(
new LatLng(Float.parseFloat(latitude), Float
.parseFloat(longitude)))
.title("Marker").title(title));
**googleMap.addPolyline(new PolylineOptions()
.add(new LatLng( Double.parseDouble(latitude1), Double.parseDouble(longitude1)),
new LatLng( Double.parseDouble(latitude), Double.parseDouble(longitude)))
.width(5).color(Color.BLUE).geodesic(true));;**
googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(
cameraLatLng, 17));
So basically that's what I have done, but what that code does is it draws a line from a source to a destination. However, I do not want to draw a line, I just want to show route direction.
like this picture http://s7.postimg.org/dwdbkq6h7/Screenshot_2015_04_14_20_40_58.png

You can use the Google Direction API to find a route between two points.

How to clear Google map v2 except few markers?

Suppose i have 100 markers on the map what i want is when i apply GoogleMap.clear(); to clear the map it clear all the other markers on the map except 2 markers and 1 polyline between them a path.
say
marker1 = GoogleMap .addMarker(new MarkerOptions().position(latLng1).title(A));
marker2 = GoogleMap .addMarker(new MarkerOptions().position(latLng2).title(B));
line = GoogleMap.addPolyline(options1);
I don't want to clear these three. I want this so user don't have to experience a blink.

There is no way to clear everything except some things. However, you can keep a reference to any markers that you want to clear and loop over them.
ArrayList<Marker> markersToClear = new ArrayList<Marker>();
marker1 = GoogleMap.addMarker(new MarkerOptions().position(latLng1).title(A));
marker2 = GoogleMap.addMarker(new MarkerOptions().position(latLng2).title(B));
marker3 = GoogleMap.addMarker(new MarkerOptions().position(latLng3).title(C));
markersToClear.add(marker2);
markersToClear.add(marker3);
for (Marker marker : markersToClear) {
marker.remove();
}
markersToClear.clear();
// marker1 left on map

Google map v2 marker not starting with my location

SupportMapFragment fm = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
googleMap = fm.getMap();
googleMap.setMyLocationEnabled(true);
Marker marker = googleMap.addMarker(new MarkerOptions()
.position(new LatLng(location.getLatitude(),location.getLongitude()))
.title("Me")
.snippet("Population: 776733"));
When I run the code,google map is supposed to show the place where I am with the marker,but the map is opening up with some other place,no my current location,and I have to move to my location manually to find the marker.

You should animateCamera on that particular location Marker like
LatLng current_loc= new LatLng(lat, lng);
mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(current_loc, 18.0f));
For more information go to https://developers.google.com/maps/documentation/android/views#moving_the_camera

try this,
googleMap.moveCamera(CameraUpdateFactory.newLatLng(new LatLng(your latitude, you longitude)));

Launch google maps after clicking Marked

I have got the following code, and what I want to do is to open "Google Maps" APP [How to go] to the marker I have set up:
// S E T M A P P O I N T
mLocationClient = new LocationClient(this, this, this);
mapFragment = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map));
map = mapFragment.getMap();
map.setMapType(GoogleMap.MAP_TYPE_NORMAL);
map.getUiSettings().setZoomControlsEnabled(true);
map.getUiSettings().setCompassEnabled(true);
map.setOnMapClickListener(this);
map.setMyLocationEnabled(true);
map.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(latitude, longitude), ZOOM));
map.clear();
addressText = GetGeolocation.getgeocoder(Date_Accept.this, latitude, longitude);
Marker marker = map.addMarker(new MarkerOptions()
.position(new LatLng(latitude, longitude))
.title(addressText)
.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED)));
marker.showInfoWindow();
How can I open "Google Maps" app to get the route to that point?

you should be able to fire an intent with the maps url and let android handle it for you
read about that here