Question

我几天前开始学习android，我想设计一个应用程序，我可以通过使用gps计算我运行的距离，时间和速度。

所以我尝试了几个例子并完成了一些教程。我写了以下代码。

但是这只是给了我gps的位置，但它没有计算距离和速度，任何人都可以告诉我我的问题在哪里以及如何解决它。

import android.app.Activity;
import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class test extends Activity implements Runnable {
     private static final long MINIMUM_DISTANCE_CHANGE_FOR_UPDATES = 1; // in Meters
        private static final long MINIMUM_TIME_BETWEEN_UPDATES = 3;

        protected LocationManager locationManager;
        Location location;
        static double n=0;
        Long s1,r1;
        double plat,plon,clat,clon,dis;
        MyCount counter;
        Thread t1;
        EditText e1;
        boolean bool=true;

    Button b1,b2,b3,b4,b5;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.gps);
        b1=(Button)findViewById(R.id.button1);//<--- current position
        b2=(Button)findViewById(R.id.button2);//<---- start moving.. calculates distance on clicking this
        b3=(Button)findViewById(R.id.button3);//<--- pause
        b4=(Button)findViewById(R.id.button4);//<-- resume
        b5=(Button)findViewById(R.id.button5);// <-- get distance
        e1=(EditText)findViewById(R.id.editText1);
        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        locationManager.requestLocationUpdates(
                LocationManager.GPS_PROVIDER, 
                MINIMUM_TIME_BETWEEN_UPDATES, 
                MINIMUM_DISTANCE_CHANGE_FOR_UPDATES,
                new MyLocationListener()
        );
        b1.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                showCurrentLocation();
            }
    });     

    }
    protected void showCurrentLocation() {

        Location location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);

        if (location != null) {
            String message = String.format(
                    "Current Location \n Longitude: %1$s \n Latitude: %2$s",
                    location.getLongitude(), location.getLatitude()
            );
            clat=location.getLatitude();
            clon=location.getLongitude();
            Toast.makeText(test.this, message,
                    Toast.LENGTH_LONG).show();
        }
        else{
            Toast.makeText(test.this, "null location",
                    Toast.LENGTH_LONG).show();
        }

    }
    public void start (View v){

        switch(v.getId()){

        case R.id.button2:
            t1=new Thread();
            t1.start();
            counter= new MyCount(30000,1000);
         counter.start();
         break;
        case R.id.button3:
            counter.cancel();
            bool=false;
            break;
        case R.id.button4:
            counter= new MyCount(s1,1000);
         counter.start();
         bool=true;
         break;
        case R.id.button5:

            double time=n*30+r1;
            Toast.makeText(test.this,"distance in metres:"+String.valueOf(dis)+"Velocity in m/sec :"+String.valueOf(dis/time)+"Time :"+String.valueOf(time),Toast.LENGTH_LONG).show();

        }


    }


    private class MyLocationListener implements LocationListener {

        public void onLocationChanged(Location location) {
            String message = String.format(
                    "New Location \n Longitude: %1$s \n Latitude: %2$s",
                    location.getLongitude(), location.getLatitude()
            );

            Toast.makeText(test.this, message, Toast.LENGTH_LONG).show();
        }

        public void onStatusChanged(String s, int i, Bundle b) {
            Toast.makeText(test.this, "Provider status changed",
                    Toast.LENGTH_LONG).show();
        }

        public void onProviderDisabled(String s) {
            Toast.makeText(test.this,
                    "Provider disabled by the user. GPS turned off",
                    Toast.LENGTH_LONG).show();
        }

        public void onProviderEnabled(String s) {
            Toast.makeText(test.this,
                    "Provider enabled by the user. GPS turned on",
                    Toast.LENGTH_LONG).show();
        }

    }
    public class MyCount extends CountDownTimer{
        public MyCount(long millisInFuture, long countDownInterval) {
        super(millisInFuture, countDownInterval);
        }
        @Override
        public void onFinish() {
            counter= new MyCount(30000,1000);
         counter.start();
         n=n+1;
        }
        @Override
        public void onTick(long millisUntilFinished) {
            s1=millisUntilFinished;
            r1=(30000-s1)/1000;
            e1.setText(String.valueOf(r1));


        }
        }

    public double getDistance(double lat1, double lon1, double lat2, double lon2) {
        double latA = Math.toRadians(lat1);
        double lonA = Math.toRadians(lon1);
        double latB = Math.toRadians(lat2);
        double lonB = Math.toRadians(lon2);
        double cosAng = (Math.cos(latA) * Math.cos(latB) * Math.cos(lonB-lonA)) +
                        (Math.sin(latA) * Math.sin(latB));
        double ang = Math.acos(cosAng);
        double dist = ang *6371;
        return dist;
    }
    @Override
    public void run() {
        while (bool){

            clat=location.getLatitude();
            clon=location.getLongitude();
            if(clat!=plat || clon!=plon){
                dis+=getDistance(plat,plon,clat,clon);
                plat=clat;
                plon=clon;

            }

        }

        }


    }

Answer 1

请注意，您没有使用distanceBetween或distanceTo方法，而是选择以自己的方式计算距离。你的公式计算了很大的圆距离吗？它看起来比它应该更简单。建议你看一下。

Android制作跑步距离计算应用程序

1 个答案: