android:当距离发生显著变化时获取位置

在Android中，当距离发生显著变化时获取位置通常涉及到使用LocationManager和LocationListener。以下是一个简单的示例，展示了如何实现这一功能：

1. 添加权限

首先，在AndroidManifest.xml中添加位置权限：

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

2. 请求运行时权限（适用于Android 6.0及以上）

如果你的应用目标API级别是23或更高，你需要在运行时请求位置权限。

import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Build;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

public class MainActivity extends AppCompatActivity {

    private static final int LOCATION_PERMISSION_REQUEST_CODE = 1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, LOCATION_PERMISSION_REQUEST_CODE);
            } else {
                startLocationUpdates();
            }
        } else {
            startLocationUpdates();
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        if (requestCode == LOCATION_PERMISSION_REQUEST_CODE) {
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                startLocationUpdates();
            } else {
                // Permission denied, show a message to the user
            }
        }
    }

    private void startLocationUpdates() {
        LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        LocationListener locationListener = new LocationListener() {
            @Override
            public void onLocationChanged(Location location) {
                // Handle location change
                double latitude = location.getLatitude();
                double longitude = location.getLongitude();
                // Do something with the new location
            }

            @Override
            public void onStatusChanged(String provider, int status, Bundle extras) {}

            @Override
            public void onProviderEnabled(String provider) {}

            @Override
            public void onProviderDisabled(String provider) {}
        };

        try {
            if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED ||
                ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
                locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, MIN_TIME_BETWEEN_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES, locationListener);
            }
        } catch (SecurityException e) {
            e.printStackTrace();
        }
    }

    private static final long MIN_TIME_BETWEEN_UPDATES = 1000 * 60 * 5; // 5 minutes
    private static final float MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters
}

解释

权限请求：首先检查并请求位置权限。
LocationManager：使用LocationManager来管理位置服务。
LocationListener：实现LocationListener接口来监听位置变化。
requestLocationUpdates：调用requestLocationUpdates方法来注册位置更新。你可以设置最小时间间隔（MIN_TIME_BETWEEN_UPDATES）和最小距离变化（MIN_DISTANCE_CHANGE_FOR_UPDATES）。