我正在尝试开发一个速度计应用程序,用于测试目的我已经编写了可以获得速度的代码,但我不确定它是否是实时速度,因为有时我看到有一些延迟,这是我的代码:
public class MainActivity extends AppCompatActivity {
LocationManager locationManager;
LocationListener locationListener;
public void startListening() {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
if (locationManager != null) {
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
}
}
}
public void updateLocationInfo(Location location){
TextView speedtextView = (TextView) findViewById(R.id.speedTextView);
speedtextView.setText("Current speed: " + location.getSpeed()*3600/1000);
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == 1) {
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
startListening();
}
}}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
locationListener = new LocationListener() {
@Override
public void onLocationChanged(Location location) {
updateLocationInfo(location);
}
@Override
public void onStatusChanged(String s, int i, Bundle bundle) {
}
@Override
public void onProviderEnabled(String s) {
}
@Override
public void onProviderDisabled(String s) {
}
};
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 1);
} else {
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
Location location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
updateLocationInfo(location);
}
}
}
}
我还要做什么吗?有没有什么特别的方法来获得实时速度?因为我使用了很多实时速度的应用程序,现在我想知道他们是怎么做到的?可能是“公平”的GPS连接吗?还是我做错了?
