java - 如何在 google maps API v2 中添加叠加层 |安卓|

Question

我最近在 Android 上使用 Google Maps API v2 时偶然发现了另一个障碍。我无法弄清楚如何添加一个叠加层，例如在 API v1 中使用经纬度在某些位置显示标记。我还希望它从使用经度和纬度的同一个城镇开始。到目前为止，我为 map 的起始位置添加了一些代码，但它没有用。我想我应该全部用 Java 而不是 XML 布局来编写，但我不知道如何处理 SupportMapFragment 来做任何事情。

这是主要 Activity ，我正在使用 SUPPORTMAPFRAGMENT 而不是 MapFragment，并且不想切换。

package com.example.maps;

import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import com.google.android.gms.maps.SupportMapFragment;

public class Main extends FragmentActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    SupportMapFragment fragment = new SupportMapFragment();
    getSupportFragmentManager().beginTransaction()
            .add(android.R.id.content, fragment).commit();
    }
}

这是 XML

<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:map="http://schemas.android.com/apk/res-auto"
  android:id="@+id/map"
   android:name="com.google.android.gms.maps.SupportMapFragment"
   android:layout_width="wrap_content"
   android:layout_height="match_parent"
   map:cameraBearing="112.5"
   map:cameraTargetLat="-33.796923"
   map:cameraTargetLng="150.922433"
   map:cameraTilt="30"
   map:cameraZoom="13"
   map:mapType="normal"
   map:uiCompass="false"
   map:uiRotateGestures="true"
   map:uiScrollGestures="false"
   map:uiTiltGestures="true"
   map:uiZoomControls="false"
   map:uiZoomGestures="true" />

编辑

新的 Java 代码(我排除了导入和包，但它们都在那里。)

public class Main extends FragmentActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    SupportMapFragment fragment = new SupportMapFragment();
    getSupportFragmentManager().beginTransaction()
            .add(android.R.id.content, fragment).commit();

    GoogleMap googleMap;
    googleMap = ((SupportMapFragment)(getSupportFragmentManager().findFragmentById(R.id.map))).getMap();
    LatLng latLng = new LatLng(-33.796923, 150.922433);
    googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
    googleMap.addMarker(new MarkerOptions()
            .position(latLng)
            .title("My Spot")
            .snippet("This is my spot!")
            .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_AZURE)));
    googleMap.getUiSettings().setCompassEnabled(true);
    googleMap.getUiSettings().setZoomControlsEnabled(true);
    googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 10));
}

新错误

01-02 01:16:53.333: D/AndroidRuntime(916): Shutting down VM
01-02 01:16:53.333: W/dalvikvm(916): threadid=1: thread exiting with uncaught    exception (group=0x40a70930)
01-02 01:16:53.363: E/AndroidRuntime(916): FATAL EXCEPTION: main
01-02 01:16:53.363: E/AndroidRuntime(916): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.maps/com.example.maps.Main}: java.lang.NullPointerException
01-02 01:16:53.363: E/AndroidRuntime(916):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
01-02 01:16:53.363: E/AndroidRuntime(916):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
01-02 01:16:53.363: E/AndroidRuntime(916):  at android.app.ActivityThread.access$600(ActivityThread.java:141)
01-02 01:16:53.363: E/AndroidRuntime(916):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
01-02 01:16:53.363: E/AndroidRuntime(916):  at android.os.Handler.dispatchMessage(Handler.java:99)
01-02 01:16:53.363: E/AndroidRuntime(916):  at android.os.Looper.loop(Looper.java:137)
01-02 01:16:53.363: E/AndroidRuntime(916):  at android.app.ActivityThread.main(ActivityThread.java:5039)
01-02 01:16:53.363: E/AndroidRuntime(916):  at java.lang.reflect.Method.invokeNative(Native Method)
01-02 01:16:53.363: E/AndroidRuntime(916):  at java.lang.reflect.Method.invoke(Method.java:511)
01-02 01:16:53.363: E/AndroidRuntime(916):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
01-02 01:16:53.363: E/AndroidRuntime(916):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
01-02 01:16:53.363: E/AndroidRuntime(916):  at dalvik.system.NativeStart.main(Native Method)
01-02 01:16:53.363: E/AndroidRuntime(916): Caused by: java.lang.NullPointerException
01-02 01:16:53.363: E/AndroidRuntime(916):  at com.example.maps.Main.onCreate(Main.java:19)
01-02 01:16:53.363: E/AndroidRuntime(916):  at android.app.Activity.performCreate(Activity.java:5104)
01-02 01:16:53.363: E/AndroidRuntime(916):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
01-02 01:16:53.363: E/AndroidRuntime(916):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
01-02 01:16:53.363: E/AndroidRuntime(916):  ... 11 more

Answer 1

您可以在 FragmentActivity 的 onCreate 中添加标记。

        GoogleMap googleMap;
        googleMap = ((SupportMapFragment)(getSupportFragmentManager().findFragmentById(R.id.map))).getMap();
        LatLng latLng = new LatLng(-33.796923, 150.922433);
        googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
        googleMap.addMarker(new MarkerOptions()
                .position(latLng)
                .title("My Spot")
                .snippet("This is my spot!")
                .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_AZURE)));
        googleMap.getUiSettings().setCompassEnabled(true);
        googleMap.getUiSettings().setZoomControlsEnabled(true);
        googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 10));

布局的端到端解决方案看起来像这样......

<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
          android:id="@+id/map"
          android:name="com.google.android.gms.maps.SupportMapFragment"
          android:layout_width="match_parent"
          android:layout_height="match_parent" />

...这样的 Activity ...

public class NameOfYourActivity extends FragmentActivity {
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.nameOfYourLayout);

    GoogleMap googleMap;
    googleMap = ((SupportMapFragment)(getSupportFragmentManager().findFragmentById(R.id.map))).getMap();
    LatLng latLng = new LatLng(-33.796923, 150.922433);
    googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
    googleMap.addMarker(new MarkerOptions()
            .position(latLng)
            .title("My Spot")
            .snippet("This is my spot!")
            .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_AZURE)));
    googleMap.getUiSettings().setCompassEnabled(true);
    googleMap.getUiSettings().setZoomControlsEnabled(true);
    googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 10));
}