如何使用intent将int []数据从一个活动传输到另一个活动

Question

我有两项活动。第一个生成整数arraylist数据，我想在第二个活动中将数据用作int []数据。我的第二项活动的代码如下：

public class maptask extends MapActivity {

    @Override


    protected boolean isRouteDisplayed() {
        return false;
    }



      @Override
      public void onCreate(Bundle icicle) {


        super.onCreate(icicle);
        Intent intent= new Intent();

        List<Integer> x=intent.getIntegerArrayListExtra("lat");
        List<Integer> y=intent.getIntegerArrayListExtra("lon");
        //receive the data from the first activity

        setContentView(R.layout.map);  



        MapView mapView = (MapView) findViewById(R.id.mapview);
        mapView.setBuiltInZoomControls(true);
        List<Overlay> mapOverlays = mapView.getOverlays();

        Drawable drawable = this.getResources().getDrawable(R.drawable.ic_action_search);
        mapoverlay itemizedoverlay = new mapoverlay(drawable, this);

        int a=0, b=0;
        for(a=0; a<x.size();a++)
        //here, the logcat shows there must be something wrong.

            for(b=0; b<y.size(); b++)
            {
                if(a==b)
                {
                    GeoPoint Point =new GeoPoint(x.get(a),y.get(b));

                    OverlayItem overlayitem = new OverlayItem(Point, "Hola, Mundo!", "I'm in Mexico City!");
                    mapOverlays.add(itemizedoverlay);
                    itemizedoverlay.addOverlay(overlayitem);

              }

        }
      }
}

为了找到问题，我首先尝试在代码的开头定义两个2 int []而不是arrarylist，并且它成功运行。因此，问题必须存在于数据类型传输或意图数据传输中。

以下是第一项活动：

公共类MainActivity扩展了Activity {

public  List<String> position = new ArrayList<String>(); 
public  List<Long> time=new ArrayList<Long>();
public  List<Integer> lat= new ArrayList<Integer>(); 
public  List<Integer> lon= new ArrayList<Integer>(); 




@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    final Button mapbutton=(Button) findViewById(R.id.button1);
    mapbutton.setOnClickListener(new OnClickListener(){
        public void onClick(View v){
            Intent intent =new Intent();
            intent.setClass(MainActivity.this, maptask.class);
            intent.putIntegerArrayListExtra("lat", (ArrayList<Integer>) lat);
            intent.putIntegerArrayListExtra("lon", (ArrayList<Integer>) lon);
                intent.putStringArrayListExtra("data", (ArrayList<String>) position);

                startActivity(intent);

            }
        });

        final Button listbutton=(Button) findViewById(R.id.button2);
        listbutton.setOnClickListener(new OnClickListener(){
            public void onClick(View v){
                Intent intent =new Intent();
                intent.setClass(MainActivity.this, list.class);
                intent.putStringArrayListExtra("data", (ArrayList<String>) position);
                //String yes="my name";
                //intent.putExtra("yes", yes);
                startActivity(intent);

            }
        });

        LocationManager locationManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
        String provider = locationManager.GPS_PROVIDER;
        Location location = locationManager.getLastKnownLocation(provider);
        locationManager.requestLocationUpdates(provider, 2000, 10, locationListener);


    } 


    private void additem(Location location){
         String latLongString = "Lat:" + location.getLatitude() + "\nLong:" + location.getLongitude();
         position.add(latLongString);
         long t=location.getTime();
         time.add(t);

    }

    private void addgeo(Location location){
        int x=(int)location.getLatitude()*1000000;
        int y=(int)location.getLongitude()*1000000;
        lat.add(x);
        lon.add(y);


    }
  //I use the addgeo to put the data into arraylist.    



private  LocationListener locationListener = new LocationListener() {
    public void onLocationChanged(Location location) {
          additem(location);
          addgeo(location);

            };
     // updateWithNewLocation(location);


//      addlayout(location);


    public void onProviderDisabled(String provider){
      //updateWithNewLocation(null);
  //    addlayout(null);

    }

    public void onProviderEnabled(String provider) {
        //updateWithNewLocation(null);
    //  addlayout(null);

    }

    public void onStatusChanged(String provider, int status, Bundle extras) {}
  };

Answer 1

如果您正在使用int[] lats，则应使用：

intent.putExtra("lat", lats);

并使用getIntArrayExtra()阅读：

int[] lats = intent.getIntArrayExtra("lat");

Answer 2

它不起作用，因为在你的第二个活动中

 Intent intent= new Intent();

应该是

Intent intent = getIntent();