第3章（第16讲） 示例16--离线地图功能
分类：C#、Android、百度地图应用； 日期：2016-02-04
一、简介
百度地图目前已经支持矢量离线地图数据的下载、更新。
使用离线地图，可满足在无网络环境下查看地图信息的需求，此外，在有离线地图的情况下，SDK会优先加载离线地图使用，减少用户流量方面的开销，为用户提供更流畅的地图服务体验。
更新离线地图增加update方法，与start方法区别开来，当检测到有城市离线包有更新，调用update方法执行更新，调用pause暂停，调用start继续
离线地图资源可通过SDK“在线下载离线包接口”下载获取。自v2.9.0起，官网不再支持地图离线包下载，所以SDK去掉“手动导入离线包接口”，SDK在线下载离线包接口仍维持不变。
二、运行截图
简介：介绍如何下载和使用离线地图。
详述：
可以搜索、下载、删除、查看离线地图。
该示例运行截图如下：
三、设计步骤
1、添加demo16_offline.xml文件
在layout文件夹下添加该文件，然后将代码改为下面的内容：
<?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" > <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="50dip" android:orientation="horizontal" > <TextView android:id="@+id/cityid" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" android:text="131" /> <!-- 隐藏输入法用 --> <LinearLayout android:layout_width="0px" android:layout_height="0px" android:focusable="true" android:focusableInTouchMode="true" /> <EditText android:id="@+id/city" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" android:text="北京" /> <Button android:id="@+id/search" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" android:background="@drawable/button_style" android:text="搜索" /> </LinearLayout> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="50dip" android:orientation="horizontal" > <TextView android:id="@+id/state" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" android:text="已下载:--" /> <Button android:id="@+id/start" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" android:background="@drawable/button_style" android:text="开始" /> <Button android:id="@+id/stop" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" android:background="@drawable/button_style" android:text="停止" /> <Button android:id="@+id/del" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" android:background="@drawable/button_style" android:text="删除" /> </LinearLayout> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/city_list" android:layout_width="match_parent" android:layout_height="50dip" android:orientation="horizontal" > <Button android:id="@+id/clButton" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" android:background="@drawable/button_style" android:text="城市列表" /> <Button android:id="@+id/localButton" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" android:background="@drawable/button_style" android:text="下载管理" /> </LinearLayout> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/citylist_layout" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="热门城市" /> <ListView android:id="@+id/hotcitylist" android:layout_width="fill_parent" android:layout_height="200dip" /> <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="全国" /> <ListView android:id="@+id/allcitylist" android:layout_width="fill_parent" android:layout_height="fill_parent" /> </LinearLayout> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/localmap_layout" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="已下载城市 " /> <ListView android:id="@+id/localmaplist" android:layout_width="fill_parent" android:layout_height="wrap_content" /> </LinearLayout> </LinearLayout>
2、添加demo16_offline_localmap_list.xml文件
在layout文件夹下添加该文件，然后将代码改为下面的内容：
<?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="horizontal" android:padding="10dip" > <TextView android:id="@+id/title" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" android:text="已下载城市 " /> <TextView android:id="@+id/update" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" android:text="" android:textColor="#FF0000" /> <TextView android:id="@+id/ratio" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" android:text="" /> <Button android:id="@+id/display" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" android:background="@drawable/button_style" android:text="查看" /> <Button android:id="@+id/remove" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_weight="1" android:background="@drawable/button_style" android:text="删除" /> </LinearLayout>
3、添加Demo16Offline.cs文件
在SrcSdkDemos文件夹下添加该文件，然后将代码改为下面的内容：
using Android.App; using Android.Content; using Android.Content.PM; using Android.OS; using Android.Util; using Android.Views; using Android.Widget; using Com.Baidu.Mapapi.Map.Offline; using System.Collections.Generic; namespace BdMapV371Demos.SrcSdkDemos { [Activity(Label = "@string/demo_name_offline", ConfigurationChanges = ConfigChanges.Orientation | ConfigChanges.KeyboardHidden, ScreenOrientation = ScreenOrientation.Sensor)] public class Demo16Offline : Activity, IMKOfflineMapListener { private MKOfflineMap mOffline = null; private TextView cidView; private TextView stateView; private EditText cityNameView; //已下载的离线地图信息列表 private IList<MKOLUpdateElement> localMapList = null; private LocalMapAdapter lAdapter = null; protected override void OnCreate(Bundle savedInstanceState) { base.OnCreate(savedInstanceState); SetContentView(Resource.Layout.demo16_offline); mOffline = new MKOfflineMap(); mOffline.Init(this); //【搜索】按钮--搜索需要下载的城市离线包 var search = FindViewById<Button>(Resource.Id.search); search.Click += delegate { IList<MKOLSearchRecord> records = mOffline.SearchCity(cityNameView.Text); if (records == null || records.Count != 1) return; cidView.Text = records[0].CityID.ToString(); }; //【开始】按钮--开始下载 var start = FindViewById<Button>(Resource.Id.start); start.Click += delegate { int cityid = int.Parse(cidView.Text); mOffline.Start(cityid); Toast.MakeText(this, "开始下载离线地图. cityid: " + cityid, ToastLength.Short).Show(); }; //【停止】按钮--暂停下载 var stop = FindViewById<Button>(Resource.Id.stop); stop.Click += delegate { int cityid = int.Parse(cidView.Text); mOffline.Pause(cityid); Toast.MakeText(this, "暂停下载离线地图. cityid: " + cityid, ToastLength.Short).Show(); }; //【删除】按钮--删除离线地图 var del = FindViewById<Button>(Resource.Id.del); del.Click += delegate { int cityid = int.Parse(cidView.Text); mOffline.Remove(cityid); Toast.MakeText(this, "删除离线地图. cityid: " + cityid, ToastLength.Short).Show(); }; //【城市列表】按钮--切换至城市列表 var clButton = FindViewById<Button>(Resource.Id.clButton); clButton.Click += delegate { LinearLayout cl = FindViewById<LinearLayout>(Resource.Id.citylist_layout); LinearLayout lm = FindViewById<LinearLayout>(Resource.Id.localmap_layout); lm.Visibility = ViewStates.Gone; cl.Visibility = ViewStates.Visible; }; //【下载管理】按钮--切换至下载管理列表 var localButton = FindViewById<Button>(Resource.Id.localButton); localButton.Click += delegate { LinearLayout cl = FindViewById<LinearLayout>(Resource.Id.citylist_layout); LinearLayout lm = FindViewById<LinearLayout>(Resource.Id.localmap_layout); lm.Visibility = ViewStates.Visible; cl.Visibility = ViewStates.Gone; }; InitView(); } private void InitView() { cidView = FindViewById<TextView>(Resource.Id.cityid); cityNameView = FindViewById<EditText>(Resource.Id.city); stateView = FindViewById<TextView>(Resource.Id.state); ListView hotCityList = FindViewById<ListView>(Resource.Id.hotcitylist); IList<string> hotCities = new List<string>(); //获取热闹城市列表 IList<MKOLSearchRecord> records1 = mOffline.HotCityList; if (records1 != null) { foreach (MKOLSearchRecord r in records1) { hotCities.Add(string.Format("{0}({1})--{2}", r.CityName, r.CityID, FormatDataSize(r.Size))); } } IListAdapter hAdapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleListItem1, hotCities); hotCityList.Adapter = hAdapter; ListView allCityList = FindViewById<ListView>(Resource.Id.allcitylist); //获取所有支持离线地图的城市 IList<string> allCities = new List<string>(); IList<MKOLSearchRecord> records2 = mOffline.OfflineCityList; if (records1 != null) { foreach (MKOLSearchRecord r in records2) { allCities.Add(string.Format("{0}({1})--{2}", r.CityName, r.CityID, FormatDataSize(r.Size))); } } IListAdapter aAdapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleListItem1, allCities); allCityList.Adapter = aAdapter; LinearLayout cl = FindViewById<LinearLayout>(Resource.Id.citylist_layout); LinearLayout lm = FindViewById<LinearLayout>(Resource.Id.localmap_layout); lm.Visibility = ViewStates.Gone; cl.Visibility = ViewStates.Visible; //获取已下过的离线地图信息 localMapList = mOffline.AllUpdateInfo; if (localMapList == null) { localMapList = new List<MKOLUpdateElement>(); } ListView localMapListView = FindViewById<ListView>(Resource.Id.localmaplist); lAdapter = new LocalMapAdapter(this); localMapListView.Adapter = lAdapter; } // 更新状态显示 public void UpdateView() { localMapList = mOffline.AllUpdateInfo; if (localMapList == null) { localMapList = new List<MKOLUpdateElement>(); } lAdapter.NotifyDataSetChanged(); } protected override void OnPause() { int cityid = int.Parse(cidView.Text); MKOLUpdateElement temp = mOffline.GetUpdateInfo(cityid); if (temp != null && temp.Status == MKOLUpdateElement.Downloading) { mOffline.Pause(cityid); } base.OnPause(); } protected override void OnResume() { base.OnResume(); } public string FormatDataSize(int size) { string ret = ""; if (size < (1024 * 1024)) { ret = Java.Lang.String.Format("%dK", size / 1024); } else { ret = Java.Lang.String.Format("%.1fM", size / (1024 * 1024.0)); } return ret; } protected override void OnDestroy() { // 退出时，销毁离线地图模块 mOffline.Destroy(); base.OnDestroy(); } //实现接口 public void OnGetOfflineMapState(int type, int state) { switch (type) { case MKOfflineMap.TypeDownloadUpdate: { MKOLUpdateElement update = mOffline.GetUpdateInfo(state); //处理下载进度更新提示 if (update != null) { stateView.Text = Java.Lang.String.Format("%s : %d%%", update.CityName, update.Ratio); UpdateView(); } } break; case MKOfflineMap.TypeNewOffline: //有新离线地图安装 Log.Debug("OfflineDemo", string.Format("add offlinemap num:{0:d}", state)); break; case MKOfflineMap.TypeVerUpdate: // 版本更新提示 // MKOLUpdateElement e = mOffline.GetUpdateInfo(state); break; } } // 离线地图管理列表适配器 public class LocalMapAdapter : BaseAdapter { private Demo16Offline offlineDemo; public LocalMapAdapter(Demo16Offline offlineDemo) { this.offlineDemo = offlineDemo; } public override int Count { get { return offlineDemo.localMapList.Count; } } public override Java.Lang.Object GetItem(int index) { return offlineDemo.localMapList[index]; } public override long GetItemId(int index) { return index; } public override View GetView(int index, View view, ViewGroup arg2) { MKOLUpdateElement e = (MKOLUpdateElement)GetItem(index); view = View.Inflate(offlineDemo, Resource.Layout.demo16_offline_localmap_list, null); InitViewItem(view, e); return view; } void InitViewItem(View view, MKOLUpdateElement e) { Button display = view.FindViewById<Button>(Resource.Id.display); Button remove = view.FindViewById<Button>(Resource.Id.remove); TextView title = view.FindViewById<TextView>(Resource.Id.title); TextView update = view.FindViewById<TextView>(Resource.Id.update); TextView ratio = view.FindViewById<TextView>(Resource.Id.ratio); ratio.Text = e.Ratio + "%"; title.Text = e.CityName; if (e.Update) { update.Text = "可更新"; } else { update.Text = "最新"; } if (e.Ratio != 100) { display.Enabled = false; } else { display.Enabled = true; } remove.Click += delegate { offlineDemo.mOffline.Remove(e.CityID); offlineDemo.UpdateView(); }; display.Click += delegate { Intent intent = new Intent(); intent.PutExtra("x", e.GeoPt.Longitude); intent.PutExtra("y", e.GeoPt.Latitude); intent.SetClass(offlineDemo, typeof(Demo02BaseMap)); offlineDemo.StartActivity(intent); }; } } } }
4、修改MainActivity.cs
在MainActivity.cs文件的demos字段定义中，去掉【示例16】下面的注释。
运行观察结果。