GroundOverlayDemoActivity.java

/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.mcommerce.sample.android.chapter09.googleMap;

import android.os.Bundle;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.GroundOverlay;
import com.google.android.gms.maps.model.GroundOverlayOptions;
import com.google.android.gms.maps.model.LatLng;
import com.google.mcommerce.sample.android.R;

/**
 * This shows how to add a ground overlay to a map.
 */
public class GroundOverlayDemoActivity extends android.support.v4.app.FragmentActivity
        implements OnSeekBarChangeListener {

    private static final int TRANSPARENCY_MAX = 100;
    private static final LatLng NEWARK = new LatLng(40.714086, -74.228697);

    private GoogleMap mMap;
    private GroundOverlay mGroundOverlay;
    private SeekBar mTransparencyBar;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.c09_ground_overlay_demo);

        mTransparencyBar = (SeekBar) findViewById(R.id.transparencySeekBar);
        mTransparencyBar.setMax(TRANSPARENCY_MAX);
        mTransparencyBar.setProgress(0);

        setUpMapIfNeeded();
    }

    @Override
    protected void onResume() {
        super.onResume();
        setUpMapIfNeeded();
    }

    private void setUpMapIfNeeded() {
        if (mMap == null) {
            mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                    .getMap();
            if (mMap != null) {
                setUpMap();
            }
        }
    }

    private void setUpMap() {
        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(NEWARK, 11));

        mGroundOverlay = mMap.addGroundOverlay(new GroundOverlayOptions()
                .image(BitmapDescriptorFactory.fromResource(R.drawable.newark_nj_1922)).anchor(0, 1)
                .position(NEWARK, 8600f, 6500f));

        mTransparencyBar.setOnSeekBarChangeListener(this);
    }

    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {
    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {
    }

    @Override
    public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
        if (mGroundOverlay != null) {
            mGroundOverlay.setTransparency((float) progress / (float) TRANSPARENCY_MAX);
        }
    }
}