第一行代码第二版(郭霖著)笔记之第十一章(百度地图)

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1. 基于位置的服务简介

  • GPS定位:基于手机内置的GPS硬件直接和卫星交互来后去当前的经纬度信息,这种定格为i方式精确度非常高,但缺点是只能在室外使用,室内基本无法接收到卫星的信号。
  • 网络定位:根据手机当前网络附近的三个基站进行测速,以此计算出手机和每个基站之间的距离,在通过三角定位确定出一个大概的位置,这种定位方式精确度一般,但优点是在室内室外都可以使用。
  • 在国内Google的网路服务不可用,所以网络定位的API失效。为了在室内和室外都可以成功定位,这里采用百度SDK来进行开发操作。

2. 获取发布版SHA1:

  • 在cmd中输入命令,然后输入密码即可:
    keytool -list -v -keystore <签名文件路径>

3. 确定自己位置的经纬度

  • 布局:
<TextView    android:id="@+id/position_text_view"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:gravity="center"    android:text="经纬度是多少"    android:textSize="25dp"    android:visibility="gone" />
  • 配置文件:
<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.fkq.baidumaps">    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"></uses-permission>    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"></uses-permission>    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"></uses-permission>    <uses-permission android:name="android.permission.READ_PHONE_STATE"></uses-permission>    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>    <uses-permission android:name="android.permission.INTERNET"></uses-permission>    <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"></uses-permission>    <uses-permission android:name="android.permission.WAKE_LOCK"></uses-permission>    <application        android:allowBackup="true"        android:icon="@mipmap/ic_launcher"        android:label="@string/app_name"        android:roundIcon="@mipmap/ic_launcher_round"        android:supportsRtl="true"        android:theme="@style/AppTheme">        <meta-data            android:name="com.baidu.lbsapi.API_KEY"            android:value="6bnAKCzjTlK27e4Wl5UBQRqQGslWoV34"></meta-data>        <activity android:name=".MainActivity">            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>        <service            android:name="com.baidu.location.f"            android:enabled="true"            android:process=":remote"></service>    </application></manifest>说明:1. 添加了多种权限。2. 添加了meta-data标签,注明APIKEY.3. 注册一个LBS SDK的服务。
  • MainActivity:
public class MainActivity extends AppCompatActivity {    public LocationClient mLocationClient;    private TextView positionText;    private StringBuilder currentPosition;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        mLocationClient = new LocationClient(getApplicationContext());        mLocationClient.registerLocationListener(new MyLocationListener());        setContentView(R.layout.activity_main);        positionText = (TextView) findViewById(R.id.position_text_view);        List<String> permissionList = new ArrayList<>();        if (ContextCompat.checkSelfPermission(MainActivity.this,                Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {            permissionList.add(Manifest.permission.ACCESS_FINE_LOCATION);        }        if (ContextCompat.checkSelfPermission(MainActivity.this,                Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {            permissionList.add(Manifest.permission.READ_PHONE_STATE);        }        if (ContextCompat.checkSelfPermission(MainActivity.this,                Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {            permissionList.add(Manifest.permission.WRITE_EXTERNAL_STORAGE);        }        if (!permissionList.isEmpty()) {            String[] permissions = permissionList.toArray(new String[permissionList.size()]);            ActivityCompat.requestPermissions(MainActivity.this, permissions, 1);        } else {            requestLocation();        }    }    private void requestLocation() {        initLocation();        mLocationClient.start();    }    private void initLocation() {        LocationClientOption option = new LocationClientOption();        option.setScanSpan(5000);        mLocationClient.setLocOption(option);    }    @Override    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {        switch (requestCode) {            case 1:                if (grantResults.length > 0) {                    for (int result : grantResults) {                        if (result != PackageManager.PERMISSION_GRANTED) {                            Toast.makeText(this, "必须同意所有权限才能使用本程序", Toast.LENGTH_SHORT).show();                            finish();                            return;                        }                    }                    requestLocation();                } else {                    Toast.makeText(this, "发生未知错误", Toast.LENGTH_SHORT).show();                    finish();                }                break;            default:        }    }    public class MyLocationListener implements BDLocationListener {        @Override        public void onReceiveLocation(BDLocation location) {            currentPosition = new StringBuilder();            currentPosition.append("纬度:").append(location.getLatitude()).append("\n");            currentPosition.append("经度:").append(location.getLongitude()).append("\n");            currentPosition.append("定位方式:");            if (location.getLocType() == BDLocation.TypeGpsLocation) {                currentPosition.append("GPS");            } else if (location.getLocType() == BDLocation.TypeNetWorkLocation) {                currentPosition.append("网络");            }            runOnUiThread(new Runnable() {                @Override                public void run() {                    positionText.setText(currentPosition);                }            });        }        @Override        public void onConnectHotSpotMessage(String s, int i) {        }    }    @Override    protected void onDestroy() {        super.onDestroy();        mLocationClient.stop();    }}说明:1. onCreate方法中创建LocationClient实例,接收一个全局的上下文参数。接着实例会注册一个监听器,当获取位置信息的时候,回调这个定位监听器。2. 运行时权限采用集合的方式,如果没有授权便添加权限到集合中,然后将List转化为数组,再调用ActivityCompat.requestPermissions方法一次性申请。onRequestPermissionsResult方法循环每个权限,如果有一个权限被拒绝,直接调用finish方法关闭当前程序,只有所有的权限被用户同意,才会调用requestLocation方法进行地理位置的定位。3. mLocationClient.start()方法进行定位,回调监听器:BDLocation.getLatitude获取位置的纬度,getLongitude获取位置的经度,getLocType获取定位方式。4. 默认情况下定位mLocationClient.start()方法只会执行一次。增加 initLocation()方法,在方法中创建LocationClientOption对象,然后调用它的setScanSpan方法设置更新的间隔,传入5000,表示5秒钟会更新一下当前的位置,意味着监听器跟随5秒设置页面的经纬度。5.活动被销毁的时候调用mLocationClient.stop()方法停止定位。

4. 选择定位模式

  • 手机定位三种模式:高精度定位、节电、仅限设备。高精度定位允许使用GPS、无线网络、蓝牙或移动网络进行定位,节电模式表示仅使用网络定位,仅限设备模式表示仅使用GPS定位。不用担心开启了GPS定位,耗费电量,因为只有定位的时候才会消耗电量。
  • initLocation方法(百度LBS)中对定位模式进行了指定:Hight_Accuracy、Battery_Saving和Device_Sensors。分别对应手机定位的三种模式。
  • 我们这里设定为高精度模式(第一行代码为设备模式):
private void initLocation() {    LocationClientOption option = new LocationClientOption();    option.setLocationMode(LocationClientOption.LocationMode.Hight_Accuracy);    mLocationClient.setLocOption(option);}说明:不管是在屋里还是屋外都可以对位置进行定位。

5. 显示看得懂的定位信息

  • 在initLocation()方法添加如下代码:
option.setIsNeedAddress(true);说明:表示我们需要获取详细的地理信息
  • 在onReceiveLocation方法中获取省市区街道等信息
currentPosition.append("国家:").append(location.getCountry()).append("\n");currentPosition.append("省:").append(location.getProvince()).append("\n");currentPosition.append("市:").append(location.getCity()).append("\n");currentPosition.append("区:").append(location.getDistrict()).append("\n");currentPosition.append("街道:").append(location.getStreet()).append("\n");注意:如果定位方式指定为设备,但是获取具体信息这一功能,还是会自动开启网络定位。

6. 显示百度地图

  • 布局:
    <com.baidu.mapapi.map.MapView        android:id="@+id/bmapView"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:clickable="true" />说明: 自定义的MapView控件,用来显示地图。
  • MainActivity添加代码:
onCreate方法中:SDKInitializer.initialize(getApplicationContext());setContentView(R.layout.activity_main);mapView = (MapView) findViewById(R.id.bmapView); @Override    protected void onResume() {        super.onResume();        mapView.onResume();    }    @Override    protected void onPause() {        super.onPause();        mapView.onPause();    }    @Override    protected void onDestroy() {        super.onDestroy();        mLocationClient.stop();        mapView.onDestroy();    }说明:1. SDKInitializer调用initialize方法,传入全局的上下文进行初始化操作,地图就会显示出来了,一句代码!2. 通过findViewById方法获取到了MapView实例。3. 在onResume、onPause和onDestroy方法中对MapView生命周期进行管理,以免浪费资源。

7. 移动到我的位置

  • 获取地图的总控制器BaiduMap类的实例。
BadiuMap baiduMap = mapView.getMap();说明:有了BiaduMap类的实例,就可以对地图进行各种各样的操作,比如设置地图的缩放级别以及将地图移动到某一个经纬度上。
  • 百度地图可以将缩放级别的取值范围定在3到19之间,值越大,地图越精细。
MapStatusUpdate update = MapStatusUpdateFactory.zoomTo(16f);baiduMap.animateMapStatus(update);
  • 借助LatLng类实现地图移动到某一个经纬度上
LatLng ll = new LatLng(location.getLatitude(), location.getLongitude());MapStatusUpdate update = MapStatusUpdateFactory.newLatLng(ll);baiduMap.animateMapStatus(update);

8. 让“我”显示在地图上

  • 取消百度地图让”我”显示在地图上的限制
baiduMap.setMyLocationEnabled(true);
  • 借助MyLocationData.Builder类封装经纬度信息
MyLocationData.Builder locationBuilder = new MyLocationData.Builder();        locationBuilder.latitude(location.getLatitude());        locationBuilder.longitude(location.getLongitude());
  • 借助MyLocationData.Builder类的build方法,让设备的位置显示在地图上
MyLocationData locationdata = locationBuilder.build();    baiduMap.setMyLocationData(locationdata);
  • 程序退出的时候,关闭我的位置显示功能
baiduMap.setMyLocationEnabled(false);

9. 附上MainActivity的代码

public class MainActivity extends AppCompatActivity {    public LocationClient mLocationClient;    private TextView positionText;    private StringBuilder currentPosition;    private MapView mapView;    private BaiduMap baiduMap;    private boolean isFirstLocate = true;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        mLocationClient = new LocationClient(getApplicationContext());        mLocationClient.registerLocationListener(new MyLocationListener());        SDKInitializer.initialize(getApplicationContext());        setContentView(R.layout.activity_main);        positionText = (TextView) findViewById(R.id.position_text_view);        mapView = (MapView) findViewById(R.id.bmapView);        baiduMap = mapView.getMap();        baiduMap.setMyLocationEnabled(true);        List<String> permissionList = new ArrayList<>();        if (ContextCompat.checkSelfPermission(MainActivity.this,                Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {            permissionList.add(Manifest.permission.ACCESS_FINE_LOCATION);        }        if (ContextCompat.checkSelfPermission(MainActivity.this,                Manifest.permission.READ_PHONE_STATE) != PackageManager.PERMISSION_GRANTED) {            permissionList.add(Manifest.permission.READ_PHONE_STATE);        }        if (ContextCompat.checkSelfPermission(MainActivity.this,                Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {            permissionList.add(Manifest.permission.WRITE_EXTERNAL_STORAGE);        }        if (!permissionList.isEmpty()) {            String[] permissions = permissionList.toArray(new String[permissionList.size()]);            ActivityCompat.requestPermissions(MainActivity.this, permissions, 1);        } else {            requestLocation();        }    }    private void requestLocation() {        initLocation();        mLocationClient.start();    }    private void initLocation() {        LocationClientOption option = new LocationClientOption();        option.setLocationMode(LocationClientOption.LocationMode.Hight_Accuracy);        option.setScanSpan(5000);        option.setIsNeedAddress(true);        mLocationClient.setLocOption(option);    }    @Override    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {        switch (requestCode) {            case 1:                if (grantResults.length > 0) {                    for (int result : grantResults) {                        if (result != PackageManager.PERMISSION_GRANTED) {                            Toast.makeText(this, "必须同意所有权限才能使用本程序", Toast.LENGTH_SHORT).show();                            finish();                            return;                        }                    }                    requestLocation();                } else {                    Toast.makeText(this, "发生未知错误", Toast.LENGTH_SHORT).show();                    finish();                }                break;            default:        }    }    private void navigateTo(BDLocation location) {        if (isFirstLocate) {            LatLng ll = new LatLng(location.getLatitude(), location.getLongitude());            MapStatusUpdate update = MapStatusUpdateFactory.newLatLng(ll);            baiduMap.animateMapStatus(update);            update = MapStatusUpdateFactory.zoomTo(16f);            baiduMap.animateMapStatus(update);            isFirstLocate = false;        }        MyLocationData.Builder locationBuilder = new MyLocationData.Builder();        locationBuilder.latitude(location.getLatitude());        locationBuilder.longitude(location.getLongitude());        MyLocationData locationdata = locationBuilder.build();        baiduMap.setMyLocationData(locationdata);    }    public class MyLocationListener implements BDLocationListener {        @Override        public void onReceiveLocation(BDLocation location) {            if (location.getLocType() == BDLocation.TypeGpsLocation || location.getLocType() == BDLocation.TypeNetWorkLocation) {                navigateTo(location);            }            currentPosition = new StringBuilder();            currentPosition.append("纬度:").append(location.getLatitude()).append("\n");            currentPosition.append("经度:").append(location.getLongitude()).append("\n");            currentPosition.append("国家:").append(location.getCountry()).append("\n");            currentPosition.append("省:").append(location.getProvince()).append("\n");            currentPosition.append("市:").append(location.getCity()).append("\n");            currentPosition.append("区:").append(location.getDistrict()).append("\n");            currentPosition.append("街道:").append(location.getStreet()).append("\n");            currentPosition.append("定位方式:");            if (location.getLocType() == BDLocation.TypeGpsLocation) {                currentPosition.append("GPS");            } else if (location.getLocType() == BDLocation.TypeNetWorkLocation) {                currentPosition.append("网络");            }            runOnUiThread(new Runnable() {                @Override                public void run() {                    positionText.setText(currentPosition);                }            });        }        @Override        public void onConnectHotSpotMessage(String s, int i) {        }    }    @Override    protected void onResume() {        super.onResume();        mapView.onResume();    }    @Override    protected void onPause() {        super.onPause();        mapView.onPause();    }    @Override    protected void onDestroy() {        super.onDestroy();        mLocationClient.stop();        mapView.onDestroy();        baiduMap.setMyLocationEnabled(false);    }}
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