Question

我想运行Google Maps API V2的示例代码。我遵循these步骤，但出现问题。我在大多数活动中都遇到了编译器错误。

错误：方法activate（LocationSource.OnLocationChangedListener）类型LocationSourceDemoActivity.LongPressLocationSource必须覆盖超类方法

在以下代码中，这些方法出错：

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

代码：

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();
}
}

我附上了图书馆，但我没有跳过Google指南中的一步。我希望你们中的某些人可以帮助我！

Answer 1

您是否使用符合Java 1.6的编译器？ @Override注释的使用情况在1.5和1.6中有所不同（请参阅this answer）。

右键单击项目节点，选择“属性” - >“Java编译器” - >“编译器符合性级别”应为1.6。

Google Maps API V2示例代码中@Override出错

1 个答案: