android - 如何在谷歌地图中添加标记？

Question

我想在谷歌地图上添加一个标记。我在我的应用程序中成功加载了 map ，但是当我尝试添加标记时，应用程序崩溃了。我不知道为什么。请有人帮助我!

我的代码:

public class BasicMapActivity extends FragmentActivity {

    private GoogleMap mMap;

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

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

    private void setUpMap() {
        mMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker"));
    }
}

Layout.xml 文件:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<fragment
    android:id="@+id/map2"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    class="com.google.android.gms.maps.SupportMapFragment" />

</LinearLayout>

Answer 1

创建方法 setUpMapIfNeeded() 并调用 onResume() 和 onCreate()

 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();
        }
    }
}

首先您需要从SupportMapFragment 中获取 map ，然后使用Marker 添加到 map 中

 mMap.addMarker(new MarkerOptions().position(new LatLng(Your_lat, Your_long)).title("Marker"));