四、Android定位与百度位置应用开发

• 功能说明

百度地图调用及定位

• 结果截图

 

 

 

• 代码分析

MainActivity.java:
package com.example.map;

import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;

import com.baidu.location.BDLocation;
import com.baidu.location.BDLocationListener;
import com.baidu.location.LocationClient;
import com.baidu.location.LocationClientOption;
import com.baidu.mapapi.SDKInitializer;
import com.baidu.mapapi.map.BaiduMap;
import com.baidu.mapapi.map.MapStatusUpdate;
import com.baidu.mapapi.map.MapStatusUpdateFactory;
import com.baidu.mapapi.map.MapView;
import com.baidu.mapapi.model.LatLng;

/*
    百度地图应用，包含定位信息和地图显示
    一般需要打开定位服务，选择高精度定位模式，有网络连接
    需要在清单文件里使用百度云服务（参见清单文件service标签）
    需要创建应用（模块）的Key，并写入清单文件（参见清单文件meta标签）
*/
public class MainActivity extends AppCompatActivity {

    LocationClient mLocationClient;  //定位客户端
    MapView mapView;  //Android Widget地图控件
    BaiduMap baiduMap;
    boolean isFirstLocate = true;

    TextView tv_Lat;  //纬度
    TextView tv_Lon;  //经度
    TextView tv_Add;  //地址

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //如果没有定位权限，动态请求用户允许使用该权限
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 1);
        }else {
            requestLocation();
        }
    }
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode) {
            case 1:
                if (grantResults[0] != PackageManager.PERMISSION_GRANTED) {
                    Toast.makeText(this, "没有定位权限！", Toast.LENGTH_LONG).show();
                    finish();
                } else {
                    requestLocation();
                }
        }
    }
    private void requestLocation() {
        initLocation();
        mLocationClient.start();
    }
    private void initLocation() {  //初始化
        mLocationClient = new LocationClient(getApplicationContext());
        mLocationClient.registerLocationListener(new MyLocationListener());
        SDKInitializer.initialize(getApplicationContext());
        setContentView(R.layout.activity_main);

        mapView = findViewById(R.id.bmapView);
        baiduMap = mapView.getMap();
        tv_Lat = findViewById(R.id.tv_Lat);
        tv_Lon = findViewById(R.id.tv_Lon);
        tv_Add = findViewById(R.id.tv_Add);

        LocationClientOption option = new LocationClientOption();
        //设置扫描时间间隔
        option.setScanSpan(1000);
        //设置定位模式，三选一
        option.setLocationMode(LocationClientOption.LocationMode.Hight_Accuracy);
        /*option.setLocationMode(LocationClientOption.LocationMode.Battery_Saving);
        option.setLocationMode(LocationClientOption.LocationMode.Device_Sensors);*/
        //设置需要地址信息
        option.setIsNeedAddress(true);
        //保存定位参数
        mLocationClient.setLocOption(option);
    }
    //内部类，百度位置监听器
    private class MyLocationListener  implements BDLocationListener {
        @Override
        public void onReceiveLocation(BDLocation bdLocation) {
            tv_Lat.setText(bdLocation.getLatitude()+"");
            tv_Lon.setText(bdLocation.getLongitude()+"");
            tv_Add.setText(bdLocation.getAddrStr());
            if(bdLocation.getLocType()==BDLocation.TypeGpsLocation || bdLocation.getLocType()==BDLocation.TypeNetWorkLocation){
                navigateTo(bdLocation);
            }
        }
    }
    private void navigateTo(BDLocation bdLocation) {
        if(isFirstLocate){
            LatLng ll = new LatLng(bdLocation.getLatitude(),bdLocation.getLongitude());
            MapStatusUpdate update = MapStatusUpdateFactory.newLatLng(ll);
            baiduMap.animateMapStatus(update);
            isFirstLocate = false;
        }
    }
    @Override
    protected void onResume() {
        super.onResume();
        mapView.onResume();
    }
    @Override
    protected void onPause() {
        super.onPause();
        mapView.onResume();
    }
    @Override
    protected void onDestroy() {
        super.onDestroy();
        mLocationClient.stop();
        mapView.onDestroy();
    }
}


activity_main.xml:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    <!--百度地图控件-->
    <com.baidu.mapapi.map.MapView
        android:id="@+id/bmapView"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:clickable="true" />
    <!--位置文本布局的背景色代码的前2位代码为透明度-->
    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="#e0000000"
        android:orientation="vertical" >
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="12dp"
            android:layout_marginTop="20dp"
            android:orientation="horizontal" >
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="纬度："
                android:textColor="#ffffff"
                android:textSize="15dp" />
            <TextView
                android:id="@+id/tv_Lat"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text=""
                android:textColor="#ffffff"
                android:textSize="15dp" />
        </LinearLayout>
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="12dp"
            android:layout_marginTop="10dp"
            android:orientation="horizontal" >
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="经度："
                android:textColor="#ffffff"
                android:textSize="15dp" />
            <TextView
                android:id="@+id/tv_Lon"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text=""
                android:textColor="#ffffff"
                android:textSize="15dp" />
        </LinearLayout>
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="10dp"
            android:layout_marginLeft="12dp"
            android:layout_marginTop="10dp"
            android:orientation="horizontal" >
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="地址："
                android:textColor="#ffffff"
                android:textSize="15dp" />

            <TextView
                android:id="@+id/tv_Add"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text=""
                android:textColor="#ffffff"
                android:textSize="15dp" />
        </LinearLayout>
    </LinearLayout>
</FrameLayout>

DemoApplication.java:
package com.example.map;

import android.app.Application;

import com.baidu.mapapi.CoordType;
import com.baidu.mapapi.SDKInitializer;

public class DemoApplication extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        //在使用SDK各组件之前初始化context信息，传入ApplicationContext
        SDKInitializer.initialize(this);
        //自4.3.0起，百度地图SDK所有接口均支持百度坐标和国测局坐标，用此方法设置您使用的坐标类型.
        //包括BD09LL和GCJ02两种坐标，默认是BD09LL坐标。
        SDKInitializer.setCoordType(CoordType.BD09LL);
    }
}

MyLocationListener.java:
package com.example.map;

import com.baidu.location.BDAbstractLocationListener;
import com.baidu.location.BDLocation;
import com.baidu.mapapi.map.BaiduMap;
import com.baidu.mapapi.map.MapView;
import com.baidu.mapapi.map.MyLocationData;

public class MyLocationListener extends BDAbstractLocationListener {
    private MapView mMapView = null;
    private BaiduMap mBaiduMap;
    @Override
    public void onReceiveLocation(BDLocation location) {
        //mapView 销毁后不在处理新接收的位置
        if (location == null || mMapView == null){
            return;
        }
        MyLocationData locData = new MyLocationData.Builder()
                .accuracy(location.getRadius())
                // 此处设置开发者获取到的方向信息，顺时针0-360
                .direction(location.getDirection()).latitude(location.getLatitude())
                .longitude(location.getLongitude()).build();
        mBaiduMap.setMyLocationData(locData);
    }
}