Question

以下代码在Android 10上不起作用，除非您通过设置手动启用该位置。当我浏览Android 10文档时，它说如果您要从可见活动中获取位置，如果是这种情况，则不需要任何前台服务，这就是我在这里未使用任何服务的原因。

而且按照Android 10准则，在授予权限后，我将调用getLastLocation函数。

实施就像，在主要活动中，我正在获取位置坐标。请帮忙，我在代码哪里出问题了？

MainActivity.java

import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.location.Location;
import android.net.Uri;
import android.os.Bundle;
import android.provider.Settings;
import androidx.annotation.NonNull;
import com.google.android.material.snackbar.Snackbar;
import androidx.core.app.ActivityCompat;
import androidx.appcompat.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.TextView;

import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;

import java.util.Locale;


    public class MainActivity extends AppCompatActivity {

    private static final String TAG = MainActivity.class.getSimpleName();

    private static final int REQUEST_PERMISSIONS_REQUEST_CODE = 34;

    
    private FusedLocationProviderClient mFusedLocationClient;
    protected Location mLastLocation;

    private String mLatitudeLabel;
    private String mLongitudeLabel;
    private TextView mLatitudeText;
    private TextView mLongitudeText;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_activity);

        mLatitudeLabel = getResources().getString(R.string.latitude_label);
        mLongitudeLabel = getResources().getString(R.string.longitude_label);
        mLatitudeText = (TextView) findViewById((R.id.latitude_text));
        mLongitudeText = (TextView) findViewById((R.id.longitude_text));

        mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
    }

    @Override
    public void onStart() {
        super.onStart();

        if (!checkPermissions()) {
            requestPermissions();
        } else {
            getLastLocation();
        }
    }

    
    @SuppressWarnings("MissingPermission")
    private void getLastLocation() {

        mFusedLocationClient.getLastLocation()
                .addOnCompleteListener(this, new OnCompleteListener<Location>() {
                    @Override
                    public void onComplete(@NonNull Task<Location> task) {
                        if (task.isSuccessful() && task.getResult() != null) {

                            mLastLocation = task.getResult();
                            Log.d("raviraj", "lat is  " +mLastLocation.getLatitude());
                            Log.d("raviraj", "long is " +mLastLocation.getLongitude());
                            mLatitudeText.setText(String.format(Locale.ENGLISH, "%s: %f",
                                    mLatitudeLabel,
                                    mLastLocation.getLatitude()));
                            mLongitudeText.setText(String.format(Locale.ENGLISH, "%s: %f",
                                    mLongitudeLabel,
                                    mLastLocation.getLongitude()));
                        } else {
                            Log.w("RAVIRAJ", "getLastLocation:exception" +task.getException());
                            showSnackbar(getString(R.string.no_location_detected));
                        }
                    }
                });
    }

    
    private void showSnackbar(final String text) {
        View container = findViewById(R.id.main_activity_container);
        if (container != null) {
            Snackbar.make(container, text, Snackbar.LENGTH_LONG).show();
        }
    }

    
    private void showSnackbar(final int mainTextStringId, final int actionStringId,
                              View.OnClickListener listener) {
        Snackbar.make(findViewById(android.R.id.content),
                getString(mainTextStringId),
                Snackbar.LENGTH_INDEFINITE)
                .setAction(getString(actionStringId), listener).show();
    }

    
    private boolean checkPermissions() {
        int permissionState = ActivityCompat.checkSelfPermission(this,
                Manifest.permission.ACCESS_FINE_LOCATION);
        return permissionState == PackageManager.PERMISSION_GRANTED;
    }

    private void startLocationPermissionRequest() {
        ActivityCompat.requestPermissions(MainActivity.this,
                new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                REQUEST_PERMISSIONS_REQUEST_CODE);
    }

    private void requestPermissions() {
        boolean shouldProvideRationale =
                ActivityCompat.shouldShowRequestPermissionRationale(this,
                        Manifest.permission.ACCESS_FINE_LOCATION);

        
        if (shouldProvideRationale) {
            Log.i(TAG, "Displaying permission rationale to provide additional context.");

            showSnackbar(R.string.permission_rationale, android.R.string.ok,
                    new View.OnClickListener() {
                        @Override
                        public void onClick(View view) {
                            // Request permission
                            startLocationPermissionRequest();
                        }
                    });

        } else {
            Log.i(TAG, "Requesting permission");
            
            startLocationPermissionRequest();
        }
    }

    
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
                                           @NonNull int[] grantResults) {
        Log.i(TAG, "onRequestPermissionResult");
        if (requestCode == REQUEST_PERMISSIONS_REQUEST_CODE) {
            if (grantResults.length <= 0) {
                // If user interaction was interrupted, the permission request is cancelled and you
                // receive empty arrays.
                Log.i(TAG, "User interaction was cancelled.");
            } else if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                // Permission granted.
                getLastLocation();
            } else {
                
                showSnackbar(R.string.permission_denied_explanation, R.string.settings,
                        new View.OnClickListener() {
                            @Override
                            public void onClick(View view) {
                                // Build intent that displays the App settings screen.
                                Intent intent = new Intent();
                                intent.setAction(
                                        Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
                                Uri uri = Uri.fromParts("package",
                                        BuildConfig.APPLICATION_ID, null);
                                intent.setData(uri);
                                intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                                startActivity(intent);
                            }
                        });
            }
        }
    }
}

Manifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.google.android.gms.location.sample.basiclocationsample" >

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


 <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/Theme.Base" >

        <meta-data
            android:name="com.google.android.geo.API_KEY"
            android:value="@string/google_maps_key" />
        <activity
            android:name=".NewMain"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

Answer 1

请在AndroidManifest.xml中添加此权限

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

并将其添加到应用程序标签

android:usesCleartextTraffic="true"

Answer 2

好了。官方文档指出在某些情况下可以为空

https://developer.android.com/training/location/retrieve-current

在设备设置中关闭了位置。即使先前已检索到最后一个位置，结果也可能为null，因为禁用位置还会清除缓存。
该设备从未记录过其位置，这可能是新设备或已恢复出厂设置的设备。
设备上的Google Play服务已重新启动，并且在服务重启后，没有活动的融合位置提供程序客户端请求位置。为避免这种情况，您可以创建一个新的客户端并自己请求位置更新。有关更多信息，请参阅接收位置更新。

在您的情况下，仅当GPS启用时，您才能获取位置信息。即使是最后一个已知的位置。

https://developer.android.com/training/location/retrieve-current#last-known

在Android 10中请求位置坐标权限的正确方法

2 个答案: