前言
在地图的使用中，尤其在导航场景下，进行GPS轨迹录制是十分必要并且有用的，本文会对于安卓系统下的轨迹录制部分做一个分享。
系统架构
对于一个GPSRecordSystem（GPS轨迹录制系统）主要分成3个部分：开始录制，录制GPS定位，结束录制并存储，如上图右方所示。在实际应用中，以导航系统为例：（1）在开始导航时（start navi）,进行录制工作的相关配置；（2）收到安卓系统的onLocationChanged的callback进行GPSLocation的记录；（3）结束导航（stop navi）时，停止记录并存入文件。
相关代码展示
用到的相关变量
private LocationManager mLocationManager; // 系统locationManager
private LocationListener mLocationListener; // 系统locationListener
private boolean mIsRecording = false; // 是否正在录制
private List<String> mGpsList; // 记录gps的list
private String mRecordFileName; // gps文件名称
- 开始录制
开始录制一般是在整个系统工作之初，比如在导航场景下，当“开始导航”时，可以开始进行“startRecordLocation” 的配置
public void startRecordLocation(Context context, String fileName) {
// 已经在录制中不进行录制
if (mIsRecording) {
return;
}
Toast.makeText(context, "start record location...", Toast.LENGTH_SHORT).show();
// 初始化locationManager和locationListener
mLocationManager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);
mLocationListener = new MyLocationListener();
try {
// 添加listener
mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, mLocationListener);
} catch (SecurityException e) {
Toast.makeText(context, "start record location error!!!", Toast.LENGTH_SHORT).show();
Log.e(TAG, "startRecordLocation Exception", e);
e.printStackTrace();
}
// 记录文件名称，笔者这里使用“realLocationRecord + routeID”形式进行记录
mRecordFileName = fileName;
if (!mRecordFileName.endsWith(".gps")) {
mRecordFileName += ".gps";
}
mIsRecording = true;
}
- 录制中记录轨迹
记录location一般是在获取安卓系统onLocationChanged回调时调用“recordGPSLocation”
public void recordGPSLocation(Location location) {
if (mIsRecording && location != null) {
// 记录location to list
mGpsList.add(locationToString(location));
}
}
locationToString工具方法
驱动导航工作的GPS轨迹点一般要包含以下几个要素，经度，纬度，精度，角度，速度，时间，海拔高度，所以在此记录下，为后期轨迹回放做准备。
private String locationToString(Location location) {
StringBuilder sb = new StringBuilder();
long time = System.currentTimeMillis();
String timeStr = gpsDataFormatter.format(new Date(time));
sb.append(location.getLatitude());
sb.append(",");
sb.append(location.getLongitude());
sb.append(",");
sb.append(location.getAccuracy());
sb.append(",");
sb.append(location.getBearing());
sb.append(",");
sb.append(location.getSpeed());
sb.append(",");
sb.append(timeStr);
sb.append(",");
sb.append(df.format((double) time / 1000.0));
// sb.append(df.format(System.currentTimeMillis()/1000.0));
// sb.append(df.format(location.getTime()/1000.0));
sb.append(",");
sb.append(location.getAltitude());
sb.append("\n");
return sb.toString();
}
- 结束录制并保存gps文件
结束录制一般作用在整个系统的结尾，例如在导航场景下，“结束导航”时停止录制调用“stopRecordLocation”
public void stopRecordLocation(Context context) {
Toast.makeText(context, "stop record location, save to file...", Toast.LENGTH_SHORT).show();
// 移除listener
mLocationManager.removeUpdates(mLocationListener);
String storagePath = StorageUtil.getStoragePath(context); // 存储的路径
String filePath = storagePath + mRecordFileName;
saveGPS(filePath);
mIsRecording = false;
}
GPS轨迹存储工具方法
private void saveGPS(String path) {
OutputStreamWriter writer = null;
try {
File outFile = new File(path);
File parent = outFile.getParentFile();
if (parent != null && !parent.exists()) {
parent.mkdirs();
}
OutputStream out = new FileOutputStream(outFile);
writer = new OutputStreamWriter(out);
for (String line : mGpsList) {
writer.write(line);
}
} catch (Exception e) {
Log.e(TAG, "saveGPS Exception", e);
e.printStackTrace();
} finally {
if (writer != null) {
try {
writer.flush();
} catch (IOException e) {
e.printStackTrace();
Log.e(TAG, "Failed to flush output stream", e);
}
try {
writer.close();
} catch (IOException e) {
e.printStackTrace();
Log.e(TAG, "Failed to close output stream", e);
}
}
}
}
StorageUtil的getStoragePath工具方法
// 存储在跟路径下/TencentMapSDK/navigation
private static final String NAVIGATION_PATH = "/tencentmapsdk/navigation";
// getStoragePath工具方法
public static String getStoragePath(Context context) {
if (context == null) {
return null;
}
String strFolder;
boolean hasSdcard;
try {
hasSdcard = Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED);
} catch (Exception e) {
Log.e(TAG, "getStoragePath Exception", e);
e.printStackTrace();
hasSdcard = false;
}
if (!hasSdcard) {
strFolder = context.getFilesDir().getPath() + NAVIGATION_PATH;
File file = new File(strFolder);
if (!file.exists()) {
file.mkdirs();
}
} else {
strFolder = Environment.getExternalStorageDirectory().getPath() + NAVIGATION_PATH;
File file = new File(strFolder);
if (!file.exists()) { // 目录不存在，创建目录
if (!file.mkdirs()) {
strFolder = context.getFilesDir().getPath() + NAVIGATION_PATH;
file = new File(strFolder);
if (!file.exists()) {
file.mkdirs();
}
}
} else { // 目录存在，创建文件测试是否有权限
try {
String newFile = strFolder + "/.test";
File tmpFile = new File(newFile);
if (tmpFile.createNewFile()) {
tmpFile.delete();
}
} catch (IOException e) {
e.printStackTrace();
Log.e(TAG, "getStoragePath Exception", e);
strFolder = context.getFilesDir().getPath() + NAVIGATION_PATH;
file = new File(strFolder);
if (!file.exists()) {
file.mkdirs();
}
}
}
}
return strFolder;
}
结果展示
最终存储在了手机目录下的navigation目录
后续工作
后续可以对于录制的gps文件讲解在导航场景下进行轨迹回放的分享