方法getSupportFragmentManager（）是未定义的类型MainActivity：安卓

Question

我收到此错误：The method getSupportFragmentManager() is undefined for the type MainActivity.当我改变了语句：

SupportMapFragment fm = (SupportMapFragment) getFragmentManager().findFragmentById(R.id.map); 

然后我收到此错误：

Multiple markers at this line 
- Cannot cast from Fragment to 
SupportMapFragment 
- Line breakpoint:MainActivity [line: 52] - 
onCreate(Bundle) 

的源代码：

package in.wptrafficanalyzer.proximitymapv2; 

import android.app.Activity; 
import android.app.Dialog; 
import android.app.PendingIntent; 
import android.content.Intent; 
import android.content.SharedPreferences; 
import android.graphics.Color; 
import android.location.LocationManager; 
import android.os.Bundle; 
import android.support.v4.app.FragmentActivity; 
import android.view.Menu; 
import android.widget.Toast; 

import com.google.android.gms.common.ConnectionResult; 
import com.google.android.gms.common.GooglePlayServicesUtil; 
import com.google.android.gms.maps.CameraUpdateFactory; 
import com.google.android.gms.maps.GoogleMap; 
import com.google.android.gms.maps.GoogleMap.OnMapClickListener; 
import com.google.android.gms.maps.GoogleMap.OnMapLongClickListener; 
import com.google.android.gms.maps.SupportMapFragment; 
import com.google.android.gms.maps.model.CircleOptions; 
import com.google.android.gms.maps.model.LatLng; 
import com.google.android.gms.maps.model.MarkerOptions; 

public class MainActivity extends Activity { 

GoogleMap googleMap; 
LocationManager locationManager; 
PendingIntent pendingIntent; 
SharedPreferences sharedPreferences; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 


    int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getBaseContext()); 

    if(status!=ConnectionResult.SUCCESS){ 

     int requestCode = 10; 
     Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status, this, requestCode); 
     dialog.show(); 

    }else {    

     SupportMapFragment fm = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map); 

     googleMap = fm.getMap(); 

     googleMap.setMyLocationEnabled(true);   


     locationManager = (LocationManager) getSystemService(LOCATION_SERVICE); 


     sharedPreferences = getSharedPreferences("location", 0); 

     String lat = sharedPreferences.getString("lat", "0"); 

     String lng = sharedPreferences.getString("lng", "0"); 

     String zoom = sharedPreferences.getString("zoom", "0"); 

     if(!lat.equals("0")){ 

      drawCircle(new LatLng(Double.parseDouble(lat), Double.parseDouble(lng))); 

      drawMarker(new LatLng(Double.parseDouble(lat), Double.parseDouble(lng))); 

      googleMap.moveCamera(CameraUpdateFactory.newLatLng(new    LatLng(Double.parseDouble(lat), Double.parseDouble(lng)))); 

      googleMap.animateCamera(CameraUpdateFactory.zoomTo(Float.parseFloat(zoom)));     


     } 


     googleMap.setOnMapClickListener(new OnMapClickListener() { 

      @Override 
      public void onMapClick(LatLng point) { 

       googleMap.clear();  

       drawMarker(point); 

       drawCircle(point);     

       Intent proximityIntent = new Intent("in.wptrafficanalyzer.activity.proximity");     

       pendingIntent = PendingIntent.getActivity(getBaseContext(), 0, proximityIntent,Intent.FLAG_ACTIVITY_NEW_TASK);      


       locationManager.addProximityAlert(point.latitude, point.longitude, 20, -1, pendingIntent); 

       SharedPreferences.Editor editor = sharedPreferences.edit(); 

       editor.putString("lat", Double.toString(point.latitude)); 

       editor.putString("lng", Double.toString(point.longitude)); 

       editor.putString("zoom", Float.toString(googleMap.getCameraPosition().zoom));    

       editor.commit();     

       Toast.makeText(getBaseContext(), "Proximity Alert is added", Toast.LENGTH_SHORT).show();      

      } 
     });  

     googleMap.setOnMapLongClickListener(new OnMapLongClickListener() {    
      @Override 
      public void onMapLongClick(LatLng point) { 
       Intent proximityIntent = new Intent("in.wptrafficanalyzer.activity.proximity"); 

       pendingIntent = PendingIntent.getActivity(getBaseContext(), 0, proximityIntent,Intent.FLAG_ACTIVITY_NEW_TASK); 

       locationManager.removeProximityAlert(pendingIntent); 

       googleMap.clear(); 

       SharedPreferences.Editor editor = sharedPreferences.edit(); 

       editor.clear(); 

       editor.commit(); 

       Toast.makeText(getBaseContext(), "Proximity Alert is removed", Toast.LENGTH_LONG).show(); 
      } 
     });   
    } 
} 

private void drawMarker(LatLng point){ 
    MarkerOptions markerOptions = new MarkerOptions();     

    markerOptions.position(point); 

    googleMap.addMarker(markerOptions); 

} 


private void drawCircle(LatLng point){ 

    CircleOptions circleOptions = new CircleOptions(); 

    circleOptions.center(point); 

    circleOptions.radius(20); 

    circleOptions.strokeColor(Color.BLACK); 

    circleOptions.fillColor(0x30ff0000); 

    circleOptions.strokeWidth(2); 

    googleMap.addCircle(circleOptions); 

} 

@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    getMenuInflater().inflate(R.menu.main, menu); 
    return true; 
} 
} 

Answer 1

您导入FragmentActivity，但你不使用它。 Activity不是来自v4，也不是来自v7支持库。这应该工作：

public class MainActivity extends FragmentActivity {