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我有一个主要活动，它解析我的 MySQL 中的 JSON 数据（表跟踪纬度和经度）。现在我想将此数据传递给我的 MapActivity 并将其显示在 Google 地图上。非常感谢任何帮助。谢谢！

这是我的 JSONactivity

public class JSONActivity extends Activity{
  private JSONObject jObject;
  private String xResult ="";
  private String url = "http://10.0.2.2/labiltrack/daftartracking.php";
  @Override
  public void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);
    setContentView(R.layout.daftartrack);
    TextView txtResult = (TextView)findViewById(R.id.TextViewResult);
    //url += "?lattitude=" + UserData.getEmail();
    xResult = getRequest(url);
    try {
      parse(txtResult);
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

 private void parse(TextView txtResult) throws Exception {
    // TODO Auto-generated method stub
    jObject = new JSONObject(xResult);
    JSONArray menuitemArray = jObject.getJSONArray("joel");
    String sret="";
    for (int i = 0; i < menuitemArray.length(); i++) {
      sret +=menuitemArray.getJSONObject(i).getString("lattitude").toString()+" : ";
      System.out.println(menuitemArray.getJSONObject(i).
        getString("lattitude").toString());
      System.out.println(menuitemArray.getJSONObject(i).
        getString("longitude").toString());
      sret +=menuitemArray.getJSONObject(i).getString("lattitude").toString()+"\n";
  }
  txtResult.setText(sret);
}
private String getRequest(String url) {
  // TODO Auto-generated method stub
  String sret="";
  HttpClient client = new DefaultHttpClient();
  HttpGet request = new HttpGet(url);
  try{
    HttpResponse response = client.execute(request);
    sret =request(response);
  }catch(Exception ex){
    Toast.makeText(this,"jo "+sret, Toast.LENGTH_SHORT).show();
  }
  return sret;
}

private String request(HttpResponse response) {
  // TODO Auto-generated method stub
  String result = "";
  try{
    InputStream in = response.getEntity().getContent();
    BufferedReader reader = new BufferedReader(new InputStreamReader(in));
    StringBuilder str = new StringBuilder();
    String line = null;
    while((line = reader.readLine()) != null){
      str.append(line + "\n");
    }
    in.close();
    result = str.toString();
  }catch(Exception ex){
    result = "Error";
  }
  return result;
}

这是我的 mapActivity

public class mapactivity extends MapActivity {
  private MapView mapView;
  MapController mc;
  GeoPoint p;
  class MapOverlays extends com.google.android.maps.Overlay {
    @Override
    public boolean draw (Canvas canvas, MapView mapView, boolean shadow, long when) {
      super.draw(canvas, mapView, shadow);
      //translate the geopoint to screen pixels
      Point screenPts = new Point();
      mapView.getProjection().toPixels(p, screenPts);
      Bitmap bmp = BitmapFactory.decodeResource(getResources (), R.drawable.pin_red);
      canvas.drawBitmap(bmp, screenPts.x, screenPts.y-50, null);
      return true;
    }
    @Override
    public boolean onTouchEvent(MotionEvent event, MapView mapView) {
      //---when user lifts his finger---
      if (event.getAction() == 1) {
        GeoPoint p = mapView.getProjection().fromPixels(
          (int) event.getX(), (int) event.getY());
        Toast.makeText(getBaseContext(),
          p.getLatitudeE6() / 1E6 + "," + p.getLongitudeE6() /1E6 ,
          Toast.LENGTH_SHORT).show();
        mc.animateTo(p);
        Geocoder geoCoder = new Geocoder(getBaseContext(), Locale.getDefault());
        try {
          List<Address> addresses = geoCoder.getFromLocation(
            p.getLatitudeE6()  / 1E6, p.getLongitudeE6() / 1E6, 1);
          String add = "";
          if (addresses.size() > 0) {
            for (int i=0; i<addresses.get(0).getMaxAddressLineIndex();i++)
              add += addresses.get(0).getAddressLine(i) + "\n";
          }
          Toast.makeText(getBaseContext(), add, Toast.LENGTH_SHORT).show();
        } catch (IOException e) {
          e.printStackTrace();
        }
        return true;
      } else
        return false;
      }
    }         

  /** Called when the activity is first created. */
  @SuppressWarnings("deprecation")
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.mapview1);
    mapView = (MapView) findViewById(R.id.mapView);
    LinearLayout zoomLayout = (LinearLayout)findViewById(R.id.zoom);
    View zoomView = mapView.getZoomControls();
    zoomLayout.addView(zoomView, new LinearLayout.LayoutParams(
      LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
    mapView.displayZoomControls(true);
    mc = mapView.getController();
    String coordinates[] = {"5.550381", "95.318699"};
    double lat = Double.parseDouble(coordinates[0]);
    double lng = Double.parseDouble(coordinates[1]);
    p = new GeoPoint((int) (lat * 1E6), (int) (lng * 1E6));
    mc.animateTo(p);
    mc.setZoom(14);
    mapView.invalidate();
    MapOverlays mapOverlay = new MapOverlays();
    List<Overlay> listOfOverlays = mapView.getOverlays();
    listOfOverlays.clear();
    listOfOverlays.add(mapOverlay);
    mapView.invalidate();
  }
  public void btnSatelitClick(View v){
    mapView.setSatellite(true);
    mapView.setStreetView(false);
  }
  public void btnjalanClick (View v){
    mapView.setSatellite(false);
    mapView.setStreetView(true);
  }
  protected boolean isRouteDisplayed() {
    //auto generate method
    return false;
  }
}

我的 JSONActivity 从 MySQL 获取数据（字段“纬度”和“经度”）到列表视图中，但现在我想在 Google 地图上显示该数据（纬度和经度）。我怎么能这样做？请帮助我，在此先感谢！

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1 回答 1

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我不确定我是否理解您的问题，但在高层次上，您可以执行以下操作：

1）您的 JSON 活动从网络调用中获取数据并将信息存储在数据库中并填充列表视图。根据我在代码中看到的内容，这里要注意一点：不要直接在主 UI 线程中进行网络调用。在蜂窝和更高版本上，这将引发异常。我建议使用AsyncTask它。

2）您可以捕获 ListView onListItemClick，它可以为您提供元素的位置，然后您可以查找列表数据集合以找出要求显示的纬度和经度。然后，您将需要使用startActivity来启动您mapActivity的并将 Extras 中的数据传递给意图。

3) 在您的mapActivity中，获取 Intent 并读取附加信息，即纬度和经度，并将这些值用于您的coordinates变量。

于 2012-07-13T04:27:33.867 回答