Java 位置服务可以工作，但一旦用户授予权限，则无法工作

因此，我使用了一个教程，几乎是复制的，只有在用户离开应用程序并返回后授予应用程序工作权限的情况下，才进行了一点修改。如果他们打开应用程序并授予权限，则不会发生任何事情，如果他们拒绝权限，则不会发生任何事情

    public class MainActivity extends AppCompatActivity {
private ArrayList<Weather> weatherLsit;
public static int REQUEST_PERMISSION=1;
private RecyclerView recyclerView;
private EditText zipCodeEditText;
LocationDataService locationDataService = new LocationDataService(MainActivity.this, this);
FusedLocationProviderClient fusedLocationProviderClient;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    recyclerView = findViewById(R.id.hourly_recycle_view);

    weatherLsit = new ArrayList<>();
    weatherLsit.add(new Weather(10, 6, R.drawable.cloudy_icon));
    weatherLsit.add(new Weather(15, 7, R.drawable.cloudy_icon));
    weatherLsit.add(new Weather(10, 8, R.drawable.cloudy_icon));
    weatherLsit.add(new Weather(60, 9, R.drawable.cloudy_icon));
    weatherLsit.add(new Weather(80, 10, R.drawable.cloudy_icon));
    weatherLsit.add(new Weather(20, 12, R.drawable.cloudy_icon));
    weatherLsit.add(new Weather(13, 12, R.drawable.cloudy_icon));
    setAdapter();
}

@Override
protected void onStart() {
    super.onStart();
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
        locationDataService.getLastLocation();
    } else {
        locationDataService.requestLocationPermission();
    }
}

private void setAdapter() {
    WeatherAdapter adapter = new WeatherAdapter(weatherLsit);
    RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getApplicationContext(), LinearLayoutManager.HORIZONTAL, false);
    recyclerView.setLayoutManager(layoutManager);
    recyclerView.setItemAnimator(new DefaultItemAnimator());
    recyclerView.setAdapter(adapter);
}

@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions,  int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if (requestCode == REQUEST_PERMISSION) {
        if (permissions.length >=0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            System.out.println("PERMISSON HAS BEEN GRANTED!");
            //do something permission is allowed here....

        } else {
            Toast.makeText(this, "Please allow the Permission", Toast.LENGTH_SHORT).show();
        }
    }

}

public类MainActivity扩展了AppCompatActivity{
私人ArrayList weatherLsit；
公共静态int请求\ u权限=1；
私人回收站；
私有EditText zipCodeEditText；
LocationDataService LocationDataService=新的LocationDataService（MainActivity.this，this）；
FusedLocationProviderClient FusedLocationProviderClient；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity_main）；
recyclerView=findViewById（R.id.hourly\u recycle\u view）；
weatherLsit=新的ArrayList（）；
weatherLsit.add（新天气（10,6,R.drawable.cloudy_图标））；
weatherLsit.add（新天气（15,7，右拉深，多云图标））；
weatherLsit.add（新天气（10,8，右侧可绘制。多云图标））；
weatherLsit.add（新天气（60,9，右侧可绘制。多云图标））；
weatherLsit.add（新天气（80,10,R.drawable.cloudy_图标））；
weatherLsit.add（新天气（20,12，右拉深，多云图标））；
weatherLsit.add（新天气（13、12、右侧可绘制多云图标））；
setAdapter（）；
}
@凌驾
受保护的void onStart（）{
super.onStart（）；
if（ContextCompat.checkSelfPermission（此，Manifest.permission.ACCESS\u位置）==PackageManager.permission\u已授予）{
locationDataService.getLastLocation（）；
}否则{
locationDataService.requestLocationPermission（）；
}
}
私有void setAdapter（）{
WeatherAdapter=新的WeatherAdapter（weatherLsit）；
RecyclerView.LayoutManager LayoutManager=新建LinearLayoutManager（getApplicationContext（），LinearLayoutManager.HORIZONTAL，false）；
recyclerView.setLayoutManager（layoutManager）；
setItemAnimator（新的DefaultItemAnimator（））；
recyclerView.setAdapter（适配器）；
}
@凌驾
public void onRequestPermissionsResult（int-requestCode、字符串[]权限、int[]grantResults）{
super.onRequestPermissionsResult（请求代码、权限、授权结果）；
if（requestCode==请求权限）{
如果（permissions.length>=0&&grantResults[0]==PackageManager.PERMISSION\u已授予）{
System.out.println（“许可已授予！”）；
//“做点什么”在这里是允许的。。。。
}否则{
Toast.makeText（这是“请允许许可”，Toast.LENGTH_SHORT.show（）；
}
}
}

}

---

由于某些原因，onRequestPermissionsResult没有被执行。我已经花了几个小时来解决这个问题，由于某些原因，我无法使它工作。

您可以尝试将权限检查放入

onCreate（）

方法中

例如：

    if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.P) {
        Log.i(TAG, "sdk < 28 Q");
        if (ActivityCompat.checkSelfPermission(context,
                Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
                && ActivityCompat.checkSelfPermission(context,
                Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            String[] strings =
                    {Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION};
            ActivityCompat.requestPermissions((Activity)context, strings, 1);
        }
    } else {
        if (ActivityCompat.checkSelfPermission(context,
                Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
                && ActivityCompat.checkSelfPermission(context,
                Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED
                && ActivityCompat.checkSelfPermission(context,
                "android.permission.ACCESS_BACKGROUND_LOCATION") != PackageManager.PERMISSION_GRANTED) {
            String[] strings = {Manifest.permission.ACCESS_FINE_LOCATION,
                    Manifest.permission.ACCESS_COARSE_LOCATION,
                    "android.permission.ACCESS_BACKGROUND_LOCATION"};
            ActivityCompat.requestPermissions((Activity)context, strings, 2);
        }
    }

并将权限代码更改为以下内容：

    if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.P) {
        Log.i(TAG, "sdk < 28 Q");
        if (ActivityCompat.checkSelfPermission(context,
                Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
                && ActivityCompat.checkSelfPermission(context,
                Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            String[] strings =
                    {Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION};
            ActivityCompat.requestPermissions((Activity)context, strings, 1);
        }
    } else {
        if (ActivityCompat.checkSelfPermission(context,
                Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
                && ActivityCompat.checkSelfPermission(context,
                Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED
                && ActivityCompat.checkSelfPermission(context,
                "android.permission.ACCESS_BACKGROUND_LOCATION") != PackageManager.PERMISSION_GRANTED) {
            String[] strings = {Manifest.permission.ACCESS_FINE_LOCATION,
                    Manifest.permission.ACCESS_COARSE_LOCATION,
                    "android.permission.ACCESS_BACKGROUND_LOCATION"};
            ActivityCompat.requestPermissions((Activity)context, strings, 2);
        }
    }