PolylineDemoActivity.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.example.mapdemo;

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.LatLng;
import com.google.android.gms.maps.model.Polyline;
import com.google.android.gms.maps.model.PolylineOptions;

import android.graphics.Color;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;

/**
 * This shows how to draw polylines on a map.
 */
public class PolylineDemoActivity extends FragmentActivity implements OnSeekBarChangeListener {
    private static final LatLng MELBOURNE = new LatLng(-37.81319, 144.96298);
    private static final LatLng SYDNEY = new LatLng(-33.87365, 151.20689);
    private static final LatLng ADELAIDE = new LatLng(-34.92873, 138.59995);
    private static final LatLng PERTH = new LatLng(-31.95285, 115.85734);

    private static final LatLng LHR = new LatLng(51.471547, -0.460052);
    private static final LatLng LAX = new LatLng(33.936524, -118.377686);
    private static final LatLng JFK = new LatLng(40.641051, -73.777485);
    private static final LatLng AKL = new LatLng(-37.006254, 174.783018);

    private static final int WIDTH_MAX = 50;
    private static final int HUE_MAX = 360;
    private static final int ALPHA_MAX = 255;

    private GoogleMap mMap;
    private Polyline mMutablePolyline;
    private SeekBar mColorBar;
    private SeekBar mAlphaBar;
    private SeekBar mWidthBar;

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

        mColorBar = (SeekBar) findViewById(R.id.hueSeekBar);
        mColorBar.setMax(HUE_MAX);
        mColorBar.setProgress(0);

        mAlphaBar = (SeekBar) findViewById(R.id.alphaSeekBar);
        mAlphaBar.setMax(ALPHA_MAX);
        mAlphaBar.setProgress(255);

        mWidthBar = (SeekBar) findViewById(R.id.widthSeekBar);
        mWidthBar.setMax(WIDTH_MAX);
        mWidthBar.setProgress(10);

        setUpMapIfNeeded();
    }

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

    private void setUpMapIfNeeded() {
        // Do a null check to confirm that we have not already instantiated the map.
        if (mMap == null) {
            // Try to obtain the map from the SupportMapFragment.
            mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                    .getMap();
            // Check if we were successful in obtaining the map.
            if (mMap != null) {
                setUpMap();
            }
        }
    }

    private void setUpMap() {

        // A simple polyline with the default options from Melbourne-Adelaide-Perth.
        mMap.addPolyline((new PolylineOptions())
                .add(MELBOURNE, ADELAIDE, PERTH));

        // A geodesic polyline that goes around the world.
        mMap.addPolyline((new PolylineOptions())
                .add(LHR, AKL, LAX, JFK, LHR)
                .width(5)
                .color(Color.BLUE)
                .geodesic(true));

        // Circle centered at Sydney.  This polyline will be mutable.
        PolylineOptions options = new PolylineOptions();
        int radius = 5;
        int numPoints = 100;
        double phase = 2 * Math.PI / numPoints;
        for (int i = 0; i <= numPoints; i++) {
            options.add(new LatLng(SYDNEY.latitude + radius * Math.sin(i * phase),
                    SYDNEY.longitude + radius * Math.cos(i * phase)));
        }
        int color = Color.HSVToColor(
                mAlphaBar.getProgress(), new float[] {mColorBar.getProgress(), 1, 1});
        mMutablePolyline = mMap.addPolyline(options
                .color(color)
                .width(mWidthBar.getProgress()));

        mColorBar.setOnSeekBarChangeListener(this);
        mAlphaBar.setOnSeekBarChangeListener(this);
        mWidthBar.setOnSeekBarChangeListener(this);

        // Move the map so that it is centered on the mutable polyline.
        mMap.moveCamera(CameraUpdateFactory.newLatLng(SYDNEY));
    }

    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {
        // Don't do anything here.
    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {
        // Don't do anything here.
    }

    @Override
    public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
        if (mMutablePolyline == null) {
            return;
        }

        if (seekBar == mColorBar) {
            mMutablePolyline.setColor(Color.HSVToColor(
                    Color.alpha(mMutablePolyline.getColor()), new float[] {progress, 1, 1}));
        } else if (seekBar == mAlphaBar) {
            float[] prevHSV = new float[3];
            Color.colorToHSV(mMutablePolyline.getColor(), prevHSV);
            mMutablePolyline.setColor(Color.HSVToColor(progress, prevHSV));
        } else if (seekBar == mWidthBar) {
            mMutablePolyline.setWidth(progress);
        }
    }
}