gistfile1.txt

public class MainActivity extends AppCompatActivity implements SlidingUpPanelLayout.PanelSlideListener{
    private SupportMapFragment mMapFragment;
    private SlidingUpPanelLayout mSlidingUpPanelLayout;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mSlidingUpPanelLayout = (SlidingUpPanelLayout) findViewById(R.id.slidingUpLayout);
        mSlidingUpPanelLayout.setPanelSlideListener(this);
        mMapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
        mMapFragment.getMapAsync(new OnMapReadyCallback() {
            @Override
            public void onMapReady(GoogleMap googleMap) {
                LatLng latLng = new LatLng(53.9, 27.5666667);
                CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(latLng, 17);
                MarkerOptions options = new MarkerOptions().position(latLng);
                googleMap.addMarker(options);
                googleMap.moveCamera(cameraUpdate);
            }
        });
    }

    @Override
    public void onPanelSlide(View panel, final float slideOffset) {
        final int panelHeight = findViewById(R.id.panel).getHeight();
        final int visiblePanelHeight = mSlidingUpPanelLayout.getPanelHeight();
        mMapFragment.getMapAsync(new OnMapReadyCallback() {
            @Override
            public void onMapReady(GoogleMap googleMap) {
                CameraPosition cameraPosition = googleMap.getCameraPosition();
                CameraUpdate cameraUpdate = CameraUpdateFactory.newCameraPosition(cameraPosition);
                googleMap.setPadding(0,0,0, (int) (visiblePanelHeight + (panelHeight - visiblePanelHeight) * slideOffset));
                googleMap.moveCamera(cameraUpdate);
            }
        });
    }

    @Override
    public void onPanelCollapsed(View panel) {

    }

    @Override
    public void onPanelExpanded(View panel) {

    }

    @Override
    public void onPanelAnchored(View panel) {

    }

    @Override
    public void onPanelHidden(View panel) {

    }
}

gistfile2.txt

<?xml version="1.0" encoding="utf-8"?>
<com.sothree.slidinguppanel.SlidingUpPanelLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/slidingUpLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="bottom"
    app:umanoOverlay="true"
    app:umanoPanelHeight="40dp"
    app:umanoShadowHeight="0dp"
    app:umanoFadeColor="@android:color/transparent">
    <fragment
        android:id="@+id/map"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:name="com.google.android.gms.maps.SupportMapFragment"
        tools:context=".MapsActivity"/>
    <TextView
        android:id="@+id/panel"
        android:layout_width="match_parent"
        android:layout_height="400dp"
        android:text="Drag me"
        android:background="@android:color/white"
        android:gravity="center_horizontal|top"/>
</com.sothree.slidinguppanel.SlidingUpPanelLayout>

I have done exactly what u said . I mean just changes in xml 's . Ahha.... mine is Hidden on start might be thats why . As i want it changed to collapsed on marker click only