Google Map V2 API指南：没有错误，但效果不佳

Question

我是Android新手。 我正在尝试制作MAP项目。.我从某个博客中找到了代码，并以可能的工作方式对其进行了编辑，但是在和输出中，它始终保持progressDialog ...永远不会结束

这是我的代码

public class LokasiActivity extends FragmentActivity{ 

public static final String USER_CURRENT_LAT = "user_current_lat";
public static final String USER_CURRENT_LONG = "user_current_long";
public static final String DESTINATION_LAT = "destination_lat";
public static final String DESTINATION_LONG = "destination_long";
public static final String DIRECTIONS_MODE = "directions_mode";
private static final LatLng AMSTERDAM = new LatLng(52.37518, 4.895439);
private static final LatLng PARIS = new LatLng(48.856132, 2.352448);
private Exception exception;
private ProgressDialog progressDialog;
private GoogleMap googleMap;
Button btnjalur;
ArrayList<LatLng> directionPoints;
SupportMapFragment fragment;
private Polyline newPolyline;
private int width, height;
private LatLngBounds latlngBounds;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.lokasi_layout);

    btnjalur = (Button)findViewById(R.id.btnJalur);

    getSreenDimanstions();

      fragment = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map));
      googleMap = fragment.getMap();

    btnjalur.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View arg0) {

            findDirections( AMSTERDAM.latitude, AMSTERDAM.longitude, PARIS.latitude, PARIS.longitude, LokasiDirection.MODE_DRIVING );   

        }
    });
}


public void handleGetDirectionsResult() {
    PolylineOptions rectLine = new PolylineOptions().width(5).color(Color.RED);

    for(int i = 0 ; i < directionPoints.size() ; i++) 
    {          
        rectLine.add(directionPoints.get(i));
    }
    if (newPolyline != null)
    {
        newPolyline.remove();
    }
    newPolyline = googleMap.addPolyline(rectLine);

        latlngBounds = createLatLngBoundsObject(AMSTERDAM, PARIS);
        googleMap.animateCamera(CameraUpdateFactory.newLatLngBounds(latlngBounds, width, height, 150));


}

private void getSreenDimanstions()
{
    Display display = getWindowManager().getDefaultDisplay();
    width = display.getWidth(); 
    height = display.getHeight(); 
}

private LatLngBounds createLatLngBoundsObject(LatLng firstLocation, LatLng secondLocation)
{
    if (firstLocation != null && secondLocation != null)
    {
        LatLngBounds.Builder builder = new LatLngBounds.Builder();    
        builder.include(firstLocation).include(secondLocation);

        return builder.build();
    }
    return null;
}

public class GetDirectionsAsyncTask extends AsyncTask<Map<String, String>, Object, ArrayList<LatLng>>
{

    public void onPreExecute()
    {
        progressDialog = new ProgressDialog(LokasiActivity.this);
        progressDialog.setMessage("Calculating directions");
        progressDialog.show();
    }


    @Override
    protected ArrayList<LatLng> doInBackground(Map<String, String>... params)
    {
        Map<String, String> paramMap = params[0];
        try
        {
            LatLng fromPosition = new LatLng(Double.valueOf(paramMap.get(USER_CURRENT_LAT)) , Double.valueOf(paramMap.get(USER_CURRENT_LONG)));
            LatLng toPosition = new LatLng(Double.valueOf(paramMap.get(DESTINATION_LAT)) , Double.valueOf(paramMap.get(DESTINATION_LONG)));
            LokasiDirection md = new LokasiDirection();
            Document doc = md.getDocument(fromPosition, toPosition, paramMap.get(DIRECTIONS_MODE));
            directionPoints = md.getDirection(doc);
            return directionPoints;
        }
        catch (Exception e)
        {
            exception = e;
            return null;
        }
    }

    public void onPostExecute()
    {
        progressDialog.dismiss();
        if (exception == null)
        {
            handleGetDirectionsResult();
        }
        else
        {
            processException();
        }
    }


    private void processException()
    {
        Toast.makeText(LokasiActivity.this, "Error retriving data", 3000).show();
    }
}

public void findDirections(double fromPositionDoubleLat, double fromPositionDoubleLong, double toPositionDoubleLat, double toPositionDoubleLong, String mode)
{
    Map<String, String> resultdestination = new HashMap<String, String>();
    resultdestination.put(USER_CURRENT_LAT, String.valueOf(fromPositionDoubleLat));
    resultdestination.put(USER_CURRENT_LONG, String.valueOf(fromPositionDoubleLong));
    resultdestination.put(DESTINATION_LAT, String.valueOf(toPositionDoubleLat));
    resultdestination.put(DESTINATION_LONG, String.valueOf(toPositionDoubleLong));
    resultdestination.put(DIRECTIONS_MODE, mode);

    new GetDirectionsAsyncTask().execute(resultdestination);
}
@Override
protected void onResume() {
    super.onResume();
    latlngBounds = createLatLngBoundsObject(AMSTERDAM, PARIS);
    googleMap.moveCamera(CameraUpdateFactory.newLatLngBounds(latlngBounds, width, height, 150));


}

}

我的代码有问题....请告诉我您是否意识到..

Answer 1

输出只是继续进行进度对话框...永无止境

您永远不会关闭进度对话框。 由于方法签名错误，因此永远不会执行onPostExecute()的代码。

更改

public void onPostExecute()

至

@Override
public void onPostExecute(ArrayList<LatLng> result)

@Override批注可帮助编译器通过在错误情况下发出错误来确保您实际上是在重写方法。