android百度地图开发——定位sdk

上一节我们介绍了android studio中配置百度地图sdk，这一节我们做一个定位的实例：
首先我们在布局文件中添加一个textview：

<?xml version="1.0" encoding="utf-8"?><android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:app="http://schemas.android.com/apk/res-auto"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context="com.example.lbstest.MainActivity">    <TextView        android:id="@+id/textView"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="TextView" /></android.support.constraint.ConstraintLayout>

接着我们在Activity的oncreate()方法中创建一个LocationClient实例，注意LocationClient的实例化要放在setContentView()之前，实例化后对LocationClient设置监听：

    public TextView positionText;    public LocationClient mlocation;    private List<String> permissionList;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        mlocation = new LocationClient(getApplicationContext());        //注册监听事件        mlocation.registerLocationListener(new MyLocationListener());        setContentView(R.layout.activity_main);        positionText = (TextView) findViewById(R.id.textView);        //申请权限        initPermission();    }

还记得我们在AndroidManifest.xml中添加的权限吗，其中有一些是敏感权限，在android6.0中需要动态申请，下面介绍一种同时申请多个权限的方法：

 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();        }

这里创建一个list集合，然后依次判断这三个权限有没有被授权，如果没授权就添加到list集合中，最后将list集合转换成数组，在一次性申请。

申请的回调：

  @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(MainActivity.this, "必须同意所以权限", Toast.LENGTH_LONG).show();                            finish();                            return;                        }                    }                    requestLocation();                } else {                    finish();                }                break;            default:        }    }

当全部权限都授权后调用requestLocation()方法，在start后开始调用监听回调：

     private void requestLocation() {        initLocation();        mlocation.start();    }    private void initLocation() {        LocationClientOption option = new LocationClientOption();        //可选，默认高精度，设置定位模式，高精度，低功耗，仅设备        option.setLocationMode(LocationClientOption.LocationMode.Hight_Accuracy);        //可选，默认0，即仅定位一次，设置发起定位请求的间隔需要大于等于1000ms才是有效的        option.setScanSpan(5000);         //设置百度坐标        option.setCoorType("bd09ll");        option.setOpenGps(true); // 打开gps        //可选，设置是否需要地址信息，默认不需要        option.setIsNeedAddress(true);        mlocation.setLocOption(option);    }

这里说一下定位mode：

• Hight_Accuracy：表示高精度模式，优先使用GPS，无法使用GPS的时候使用网络定位。
• Battery_Saving：节电模式，只是用网络定位。
• Device_Sensors：传感器模式，只是用GPS定位。

LocationClient的监听：

 public class MyLocationListener implements BDLocationListener {        @Override        public void onReceiveLocation(BDLocation bdLocation) {            Log.i("info", "listener");            final StringBuilder currentPosition = new StringBuilder();            currentPosition.append("经度：").append(bdLocation.getLatitude()).append("\n");            currentPosition.append("纬度：").append(bdLocation.getLongitude()).append("\n");            currentPosition.append("省：").append(bdLocation.getProvince()).append("\n");            currentPosition.append("市：").append(bdLocation.getCity()).append("\n");            currentPosition.append("区：").append(bdLocation.getDistrict()).append("\n");            currentPosition.append("街道：").append(bdLocation.getStreet()).append("\n");            currentPosition.append("定位方式：");            if (bdLocation.getLocType()== BDLocation.TypeGpsLocation) {                currentPosition.append("gps");            } else if (bdLocation.getLocType()==BDLocation.TypeNetWorkLocation) {                currentPosition.append("net");            }            Log.i("info", currentPosition.toString());            runOnUiThread(new Runnable() {                @Override                public void run() {                    positionText.setText(currentPosition);                }            });        }        @Override        public void onConnectHotSpotMessage(String s, int i) {        }    }

填坑：监听方法是实现在子线程中的，在这里不能做更新ui的操作。
最后在Activity的onDestroy()方法中调用stop函数：

    @Override    protected void onDestroy() {        super.onDestroy();        mlocation.stop();    }

填坑：我们把定位方式设置为高精度，这样当开启GPS的时候就会使用GPS定位，但是使用GPS的前提是在室外，否则即使开了GPS 也不能用。
运行图：

完整代码：

public class MainActivity extends AppCompatActivity {    public TextView positionText;    public LocationClient mlocation;    private List<String> permissionList;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        mlocation = new LocationClient(getApplicationContext());        mlocation.registerLocationListener(new MyLocationListener());        setContentView(R.layout.activity_main);        positionText = (TextView) findViewById(R.id.textView);        initPermission();    }    private void initPermission() {        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();        mlocation.start();    }    private void initLocation() {        LocationClientOption option = new LocationClientOption();        //可选，默认高精度，设置定位模式，高精度，低功耗，仅设备        option.setLocationMode(LocationClientOption.LocationMode.Hight_Accuracy);        //可选，默认0，即仅定位一次，设置发起定位请求的间隔需要大于等于1000ms才是有效的        option.setScanSpan(5000);        //可选，设置是否需要地址信息，默认不需要        option.setIsNeedAddress(true);        mlocation.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(MainActivity.this, "必须同意所以权限", Toast.LENGTH_LONG).show();                            finish();                            return;                        }                    }                    requestLocation();                } else {                    finish();                }                break;            default:        }    }    public class MyLocationListener implements BDLocationListener {        @Override        public void onReceiveLocation(BDLocation bdLocation) {            Log.i("info", "listener");            final StringBuilder currentPosition = new StringBuilder();            currentPosition.append("经度：").append(bdLocation.getLatitude()).append("\n");            currentPosition.append("纬度：").append(bdLocation.getLongitude()).append("\n");            currentPosition.append("省：").append(bdLocation.getProvince()).append("\n");            currentPosition.append("市：").append(bdLocation.getCity()).append("\n");            currentPosition.append("区：").append(bdLocation.getDistrict()).append("\n");            currentPosition.append("街道：").append(bdLocation.getStreet()).append("\n");            currentPosition.append("定位方式：");            if (bdLocation.getLocType()== BDLocation.TypeGpsLocation) {                currentPosition.append("gps");            } else if (bdLocation.getLocType()==BDLocation.TypeNetWorkLocation) {                currentPosition.append("net");            }            Log.i("info", currentPosition.toString());            runOnUiThread(new Runnable() {                @Override                public void run() {                    positionText.setText(currentPosition);                }            });        }        @Override        public void onConnectHotSpotMessage(String s, int i) {        }    }    @Override    protected void onDestroy() {        super.onDestroy();        mlocation.stop();    }}

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