我一直在尝试将我的GeoPoints添加到itemizedOverlay数组中，以便在地图上绘制点。不幸的是，此时应用程序崩溃了。
我的代码： 包com.example.phooogle;
public class GoogleMapsAppActivity extends MapActivity {
private MapView mapView;
private MapController mc;
private MyLocationOverlay myLocationOverlay;
private myMapService mms;
String[] ms;
private LocationManager lm;
private LocationListener locationListener;
private MyLocationOverlay myLocOverlay;
GeoPoint p;
GeoPoint progress1[];
List<GeoPoint> geoPointsArray = new ArrayList<GeoPoint>();
int latitude;
int longitude;
private ProgressDialog progress;
MotionEvent event;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_cool_map);
progress= new ProgressDialog(this);
progress.setIndeterminate(true);
progress.setMessage("I am thinking");
InitTask init_task= new InitTask();
init_task.execute("144.963620993985", "-37.8140023779914", "20", "Litter Bin");
try {
String[] arrs = init_task.strArr2;
//Log.d(" print points", " Array Size " + arrs.length);
Drawable makerDefault = this.getResources().getDrawable(R.drawable.poke);
MirItemizedOverlay itemizedOverlay = new MirItemizedOverlay(makerDefault);
for(int j=0; j<arrs.length ;j++)
{
double y =0;
double x =0;
if(j == 1)
{
/// x
//Log.d("Results", "2If statem " + strArr2[j] );
x = Double.parseDouble(arrs[j]);
y = Double.parseDouble(arrs[j+1]);
//Log.d(" print points", "lat " + x + " long" + y);
itemizedOverlay.addOverlayItem((int) x , (int) y , "La trobe");
mapView.getOverlays().add(itemizedOverlay );
}
}
MapController mc = mapView.getController();
mc.setCenter(new GeoPoint((int) (1E6 * -37.720754), (int) (1E6 * 145.048798))); // Some where .
mc.zoomToSpan(itemizedOverlay.getLatSpanE6(), itemizedOverlay.getLonSpanE6());
} finally {}
initMap();
initMyLocation();
// theRouteDraw();
/*
Drawable makerDefault = this.getResources().getDrawable(R.drawable.poke);
MirItemizedOverlay itemizedOverlay = new MirItemizedOverlay(makerDefault);
itemizedOverlay.addOverlayItem(init_task.geoPointsArray, "La trobe");
mapView.getOverlays().add(itemizedOverlay );
MapController mc = mapView.getController();
mc.setCenter(new GeoPoint((int) (1E6 * -37.720754), (int) (1E6 * 145.048798))); // Some where .
mc.zoomToSpan(itemizedOverlay.getLatSpanE6(), itemizedOverlay.getLonSpanE6());
for (int i = 0; i < geoPointsArray.size() ; i++)
{
Log.d(" print points", " points " + geoPointsArray.get(i));
}*/
// Log.d(" print points", " Size " + init_task.geoPointsArray.size());
/*
mapView = (MapView) findViewById(R.id.mapview);
List<Overlay> mapOverlays = mapView.getOverlays();
//add any icon here for the marker
Drawable drawable = GoogleMapsAppActivity.this.getResources().getDrawable(R.drawable.poke);
MapViewItemizedOverlay itemizedOverlay = new MapViewItemizedOverlay(drawable,this);
//use your array here instead
//GeoPoint point1 = new GeoPoint(lat,lng);
OverlayItem overlayitem1 = new OverlayItem(point1, "Info", "You are here!" );
itemizedOverlay.addOverlay(overlayitem1);
mapOverlays.add(itemizedOverlay);
*/
}
private void initMap()
{
mapView = (MapView) findViewById(R.id.mapview);
mapView.setBuiltInZoomControls(true);
// mapView.setStreetView(true);
mc = mapView.getController();
}
public void theRouteDraw(GeoPoint p){
mc.animateTo(p);
mc.setZoom(13);
mapView.invalidate();
mapView.setSatellite(true);
}
private void initMyLocation() {
myLocOverlay = new MyLocationOverlay(this, mapView);
myLocOverlay.enableMyLocation();
mapView.getOverlays().add(new myLocOverlay());
}
@Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
class myLocOverlay extends Overlay{
public void draw(Canvas canvas, MapView mapv, boolean shadow){
super.draw(canvas, mapv, shadow);
Projection projection = mapView.getProjection();
Path p1 = new Path();
for (int i = 0; i < geoPointsArray.size(); i++) {
if (i == geoPointsArray.size() - 1) {
break;
}
Point from = new Point();
Point to = new Point();
projection.toPixels(geoPointsArray.get(i), from);
projection.toPixels(geoPointsArray.get(i + 1), to);
p1.moveTo(from.x, from.y);
p1.lineTo(to.x, to.y);
}
Paint mPaint = new Paint();
mPaint.setStyle(Style.STROKE);
mPaint.setColor(Color.BLACK);
mPaint.setAntiAlias(true);
mPaint.setStrokeWidth(4);
canvas.drawPath(p1, mPaint);
super.draw(canvas, mapView, shadow);
}
}
private class InitTask extends AsyncTask<String, GeoPoint, List<GeoPoint>> {
List<GeoPoint> geoPointsArray = new ArrayList<GeoPoint>();
GeoPoint p;
private ProgressDialog progressDialog;
private String rst = " " ;
private String[] strArr1;
private String[] strArr2;
protected void onPreExecute() {
//progress.show();
}
@Override
protected List<GeoPoint> doInBackground(String... arg0) {
String result = "";
int responseCode = 0;
int executeCount = 0;
HttpResponse response;
StringBuilder sb = new StringBuilder();
String line;
try
{
HttpClient client = new DefaultHttpClient();
HttpGet httppost = new HttpGet("http://xxxx/ccvo/mel-asset-data/query.php?lon="+ arg0[0].toString() + "&lat="+ arg0[1].toString() +"&within=" + arg0[2].toString() + "&keyword="+ arg0[3].toString().replace(" ", "%20"));
do
{
// progressDialog.setMessage("Passing paratmeters.. ("+(executeCount+1)+"/5)");
// Execute HTTP Post Request
executeCount++;
response = client.execute(httppost);
responseCode = response.getStatusLine().getStatusCode();
} while (executeCount < 5 && responseCode == 408);
BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
while ((line = rd.readLine()) != null)
{
result = line.trim();
sb.append(line);
}
}catch (Exception e2) {
responseCode = 408;
e2.printStackTrace();
}
rst = result.toString();
// splits everything
if(rst != null && rst.length() > 0)
{
strArr1 = rst.split("\\|");
for(int i=0;i<strArr1.length;i++)
{
// Log.d("Results", "Array size1.1 " + i);
Log.v("Results", "Array split1.2 " + strArr1[i] );
if(strArr1[i] != null && strArr1[i].length() >0 && strArr1[i].contains(","))
{
strArr2 = strArr1[i].split(",");
for(int j=0; j<strArr2.length ;j++)
{
double y =0;
double x =0;
if(j == 1)
{
/// x
//Log.d("Results", "2If statem " + strArr2[j] );
x = Double.parseDouble(strArr2[j]);
y = Double.parseDouble(strArr2[j+1]);
geoPointsArray.add(new GeoPoint((int)(x*1e6), (int)(y*1e6)));
Log.d("geoPointsArray", "geoPointsArray " + geoPointsArray.toString() );
}
}
}
}
}
return geoPointsArray;
}
@Override
protected void onProgressUpdate(GeoPoint... progress1) {
theRouteDraw(progress1[0]);
geoPointsArray.add(progress1[0]);
int lon=progress1[0].getLongitudeE6();
int lat=progress1[0].getLatitudeE6();
GeoPoint p2=new GeoPoint(lon,lat);
geoPointsArray.add(p2);
initMyLocation();
}
@Override
protected void onPostExecute(List<GeoPoint> geoPointsArray)
{
//super.onPostExecute(geoPointsArray);
progress.dismiss();
//startActivity(i);
//i.getCharExtra("Geop", geoPointsArray);
Log.d("Lista", " check " + geoPointsArray.size());
// theRouteDraw(geoPointsArray);
}
}
}
我的MirItemizedOverlay类：
class MirItemizedOverlay extends ItemizedOverlay {
private List<OverlayItem> mOverlays = new ArrayList<OverlayItem>();
public MirItemizedOverlay(Drawable defaultMarker) {
super(boundCenterBottom(defaultMarker));
// TODO Auto-generated constructor stub
}
@Override
protected OverlayItem createItem(int i) {
return mOverlays.get(i);
}
@Override
public int size() {
return mOverlays.size();
}
public void addOverlayItem(OverlayItem overlayItem) {
mOverlays.add(overlayItem);
populate();
}
@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();
}
return false;
}
private Context getBaseContext() {
// TODO Auto-generated method stub
return null;
}
public void addOverlayItem(int lat, int lon, String title) {
GeoPoint point = new GeoPoint(lat, lon);
OverlayItem overlayItem = new OverlayItem(point, title, null);
addOverlayItem(overlayItem);
}
/* public void addOverlayItem(GeoPoint point , String title) {
OverlayItem overlayItem = new OverlayItem(point, title, null);
addOverlayItem(overlayItem);
//GeoPoint point = new GeoPoint(lat, lon);
}*/
}
错误：
: E/AndroidRuntime(2752): FATAL EXCEPTION: main
: E/AndroidRuntime(2752): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.phooogle/com.example.phooogle.GoogleMapsAppActivity}: java.lang.NullPointerException
: E/AndroidRuntime(2752): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
: E/AndroidRuntime(2752): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
: E/AndroidRuntime(2752): at android.app.ActivityThread.access$600(ActivityThread.java:130)
: E/AndroidRuntime(2752): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
: E/AndroidRuntime(2752): at android.os.Handler.dispatchMessage(Handler.java:99)
: E/AndroidRuntime(2752): at android.os.Looper.loop(Looper.java:137)
: E/AndroidRuntime(2752): at android.app.ActivityThread.main(ActivityThread.java:4745)
: E/AndroidRuntime(2752): at java.lang.reflect.Method.invokeNative(Native Method)
: E/AndroidRuntime(2752): at java.lang.reflect.Method.invoke(Method.java:511)
: E/AndroidRuntime(2752): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
: E/AndroidRuntime(2752): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
: E/AndroidRuntime(2752): at dalvik.system.NativeStart.main(Native Method)
: E/AndroidRuntime(2752): Caused by: java.lang.NullPointerException
: E/AndroidRuntime(2752): at com.example.phooogle.GoogleMapsAppActivity.onCreate(GoogleMapsAppActivity.java:68)
我尝试了几种方法，比如我尝试更改addOverlayItem方法以接受来自AsyncTask返回的GeoPoit，但也失败了。我差不多给了我这个。 ：）
更新 问题解决了。这是修复：
try {
//String[] arrs = init_task.strArr2;
List<GeoPoint> geoL = init_task.get();
//Log.d(" Get the size " , " Geo List " + geoL.get(1).toString());
mapView = (MapView) findViewById(R.id.mapview);
mapView.setBuiltInZoomControls(true);
mc = mapView.getController();
List<Overlay> listOfOverlays = mapView.getOverlays();
Drawable drawable = this.getResources().getDrawable(R.drawable.poke);
MyItemizedOverlay itemizedoverlay = new MyItemizedOverlay(drawable, this);
for ( int i = 0; i < geoL.size() ; i++)
{
OverlayItem overlayitem1 = new OverlayItem(geoL.get(i), Selectedword + "s found! " , "It's withing " + selectedDistance + " To your position");
itemizedoverlay.addOverlay(overlayitem1);
listOfOverlays.add(itemizedoverlay);
}
//mc.animateTo(geoL.get(1));
mc.setCenter(new GeoPoint((int) (1E6 * gps.getLatitude() ), (int) (1E6 * gps.getLongitude() ))); // Some where .
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
} finally {}
initMap();
initMyLocation();
// theRouteDraw();
答案 0 :(得分：0)
您的问题是mapView为空，您尚未调用initMap()。这会导致mapView.getOverlays().add(itemizedOverlay );失败。