Question

I want to run the sample codes for Google Maps API V2. I followed these steps, but a problem occurs. I have got a compiler error in the most Activities.

Error: The method activate(LocationSource.OnLocationChangedListener)
of type LocationSourceDemoActivity.LongPressLocationSource must
override a superclass method

In the following code these methods got an error:

public void activate(OnLocationChangedListener listener)
public void deactivate()
public void onMapLongClick(LatLng point)

Code:

package com.example.mapdemo;

import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMap.OnMapLongClickListener;
import com.google.android.gms.maps.LocationSource;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;

import android.app.Activity;
import android.location.Location;
import android.os.Bundle;


/**
 * This shows how to use a custom location source.
 */
public class LocationSourceDemoActivity extends android.support.v4.app.FragmentActivity {
    /**
     * A {@link LocationSource} which reports a new location whenever a user long presses the map at
     * the point at which a user long pressed the map.
     */
    private static class LongPressLocationSource implements LocationSource, OnMapLongClickListener {
        private OnLocationChangedListener mListener;
    /**
     * Flag to keep track of the activity's lifecycle. This is not strictly necessary in this
     * case because onMapLongPress events don't occur while the activity containing the map is
     * paused but is included to demonstrate best practices (e.g., if a background service were
     * to be used).
     */
    private boolean mPaused;

    @Override
    public void activate(OnLocationChangedListener listener) {
        mListener = listener;
    }

    @Override
    public void deactivate() {
        mListener = null;
    }

    @Override
    public void onMapLongClick(LatLng point) {
        if (mListener != null && !mPaused) {
            Location location = new Location("LongPressLocationProvider");
            location.setLatitude(point.latitude);
            location.setLongitude(point.longitude);
            location.setAccuracy(100);
            mListener.onLocationChanged(location);
        }
    }

    public void onPause() {
        mPaused = true;
    }

    public void onResume() {
        mPaused = false;
    }

}

private LongPressLocationSource mLocationSource;

private GoogleMap mMap;

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

    mLocationSource = new LongPressLocationSource();

    setUpMapIfNeeded();
}

@Override
protected void onResume() {
    super.onResume();
    setUpMapIfNeeded();

    mLocationSource.onResume();
}

private void setUpMapIfNeeded() {
    // Do a null check to confirm that we have not already instantiated the map.
    if (mMap == null) {
        // Try to obtain the map from the SupportMapFragment.
        mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap();
        // Check if we were successful in obtaining the map.
        if (mMap != null) {
            setUpMap();
        }
    }
}

private void setUpMap() {
    mMap.setLocationSource(mLocationSource);
    mMap.setOnMapLongClickListener(mLocationSource);
    mMap.setMyLocationEnabled(true);
}

@Override
protected void onPause() {
    super.onPause();
    mLocationSource.onPause();
}
}

I attached the library and I haven’t skipped a step from Google’s guide.
I hope somebody of you can help me!

Answer 1

Do you use a java 1.6 compliant compiler? The usage of the @Override annotation is different in 1.5 and 1.6 (see this answer).

Right-click on your project node, choose “Properties”–>”Java Compiler”–>”Compiler compliance level” should be 1.6.