Question

这是我班级的代码。文本视图位于活动中，我的目标只是在文本视图中显示纬度和经度。现在，当我运行应用程序时，看起来没有任何事情发生。文本视图只显示＆＃34; Textview＆＃34;。

public class MBTATracker extends Activity {

public LocationManager locationManager;
public LocationListener locationListener;
public double latittudenumber;
public double longitudenumber;

TextView lat;
TextView longitude;


@TargetApi(Build.VERSION_CODES.M)
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.mbta_tracker);
    lat = (TextView) findViewById(R.id.latitude_label);
    longitude = (TextView) findViewById(R.id.longitude_label);

    locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
    locationListener = new LocationListener() {

        @Override
        public void onLocationChanged(Location location) {
            latittudenumber = location.getLatitude();
            longitudenumber = location.getLongitude();
            lat.setText(Double.toString(latittudenumber));
            longitude.setText(Double.toString(longitudenumber));

        }

        @Override
        public void onStatusChanged(String provider, int status, Bundle  extras) {

        }

         @Override
         public void onProviderEnabled(String provider) {

        }

        @Override
        public void onProviderDisabled(String provider) {
            Intent intent = new Intent (Settings.ACTION_LOCALE_SETTINGS);
            startActivity (intent);

        }
    };
    locationManager.requestLocationUpdates("gps", 5000, 0,locationListener);

       if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
               if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
                != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission
                (this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            requestPermissions(new String[]{
                    Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION,
                    Manifest.permission.INTERNET

            }, 10);
            return;

        }

    } else {

    }

}


public void onRequestPermissionResult (int requestCode, String [] permissions,int [] grantResults){
    switch (requestCode) {
        case 10:
            if (grantResults.length>0 && grantResults[0] == PackageManager.PERMISSION_GRANTED);
               return;

    }

}

}

以下是XML：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">

<TextView
    android:id="@+id/latitude_label"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentStart="true"
    android:layout_below="@+id/local_mbta_list"
    android:layout_marginStart="40dp"
    android:layout_marginTop="91dp"
    android:text="TextView" />

<TextView
    android:id="@+id/longitude_label"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignBottom="@+id/latitude_label"
    android:layout_alignParentEnd="true"
    android:layout_marginEnd="107dp"
    android:text="TextView" />
</RelativeLayout>

Answer 1

GPS系统非常慢，您可以通过网络获取坐标。 Here是官方的Android开发者＆＃39;引导。

事实上，要以最快的方式检索坐标，您可以使用它：

  Location loc;
        try {
            loc = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
        }catch (Exception e){
//SecurityException if permissions are not enabled
            loc = null;
            e.printStackTrace();
        }

        if(loc!=null){//We can use coordinates, yay!
            longitude = (float) loc.getLongitude();
            latitude = (float) loc.getLatitude();
            txtLatLng.setText(getString(R.string.latitude).concat(Float.toString(latitude)).concat(" ").concat(getString(R.string.longitude).concat(Float.toString(longitude))));
        }else{//No last location updated so we must use slow GPS method
                    locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);}

Source of this code

使用位置管理器和位置监听器显示坐标

1 个答案: