Question

我想传递一些String数组和该数组的大小，以便在地图活动上显示位置。但问题是我无法在onCreate方法的顶部声明字符串数组并且它是在因为我使用intent来传递变量，所以在create方法上。因此我无法在onMapReady方法中使用这些数组。

我的代码如下，在我的第一个活动中

Intent SSMapIntent =new
Intent(SchoolSelectorMainActivity.this,MapsActivity.class);
        SSMapIntent.putExtra("maxDistance",Str_maxdistance);
        SSMapIntent.putExtra("source", 1);
        SSMapIntent.putExtra("listCount",listCount);
        if(listCount!=0){
            SSMapIntent.putExtra("nameList",nameListIntent);
            SSMapIntent.putExtra("typeList", typeListIntent);
            SSMapIntent.putExtra("distanceList",distanceListIntent);
            SSMapIntent.putExtra("latitude",latListIntent);
            SSMapIntent.putExtra("longitude",lngListIntent);
        } 
        startActivity(SSMapIntent);

我的地图活动

public class MapsActivity extends FragmentActivity implements
OnMapReadyCallback {

private GoogleMap mMap;
int source,tempInt,listCount;
String message1="",message2="",message3="",message4="";
String [][] selectedListTxt = new String[listCount][3];//for get name,lat,lng
double maxDistance;

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);
    // Obtain the SupportMapFragment and get notified when the map is ready to be used.
    SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
            .findFragmentById(R.id.map);
    mapFragment.getMapAsync(this);

    Intent intent = this.getIntent();
    Bundle bundle = intent.getExtras();
    source=bundle.getInt("source");
    maxDistance=bundle.getDouble("maxDistance");
    if (source==1){
        listCount=bundle.getInt("listCount");

    }
    if (listCount!=0) {
        String[] nameListMap = bundle.getStringArray("nameList");
        String[] typeListMap = bundle.getStringArray("typeList");
        String[] distanceListMap= bundle.getStringArray("distanceList");
        double [] latListMap=bundle.getDoubleArray("latitude");
        double [] lngListMap=bundle.getDoubleArray("longitude");
    }
}
@Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;

    //Here i can't use nameListMap,latListMap,lngListMap
      }
    }

Answer 1

您可以针对您的情况使用不同的方法。它不仅取决于当前的情况，还取决于未来可能的变化，数据的复杂程度。例如，您可以创建parceable对象，您可以在其中放置字符串，双精度等，或者从数据中创建json并将其作为字符串发送。您可以看到有关它的更多信息How to send an object from one Android Activity to another using Intents?

Answer 2

创建一个Util类（最好将此类声明为signleton）并使用public关键字声明这些数组，并在 MapsActivity 类中使用这些数组。
完成工作后不要忘记将它们赋值为null。但我无法解释为什么你不能在onCreate方法的顶部声明字符串数组。

Answer 3

    private GoogleMap mMap;
    int source,tempInt,listCount;
    String message1="",message2="",message3="",message4="";
    String [][] selectedListTxt = new String[listCount][3];//for get name,lat,lng
    double maxDistance;
    //global definition of required changes   
    String[] nameListMap=null;
    String[] typeListMap =null;
    String[] distanceListMap=null;
    double [] latListMap=null;
      double [] lngListMap=null;
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);

        Intent intent = this.getIntent();
        Bundle bundle = intent.getExtras();
        source=bundle.getInt("source");
        maxDistance=bundle.getDouble("maxDistance");
        if (source==1){
            listCount=bundle.getInt("listCount");

        }
        if (listCount!=0) {
            nameListMap = bundle.getStringArray("nameList");
             typeListMap = bundle.getStringArray("typeList");
            distanceListMap= bundle.getStringArray("distanceList");
             latListMap=bundle.getDoubleArray("latitude");
             lngListMap=bundle.getDoubleArray("longitude");
        }
    }
    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;

        //Here i can't use nameListMap,latListMap,lngListMap
        // now you can use your variables here
        //SYSO(nameListMap.length)
          }
        }

请查看我在您的代码中所做的更改...我在全球范围内确认您所需的Varibale ......

如何将常量和其他变量发送到另一个活动？

3 个答案: