Android 无法解析符号“；locationListener"；-安卓

我在实现

LocationListener

时遇到问题

import androidx.appcompat.app.AppCompatActivity;

import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.location.Address;
import android.location.Criteria;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.widget.TextView;
import java.io.IOException;
import java.util.List;
import java.util.Locale;

public class MainActivity extends AppCompatActivity {
    TextView latitudeTV;
    TextView longitudeTV;
    TextView altitudeTV;
    TextView locationNameTV;
    double latitude;
    double longitude;
    double altitude;
    String locationName;

    LocationManager locationManager;
    Location location;

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

        latitudeTV = (TextView) findViewById(R.id.latitude);
        longitudeTV = (TextView) findViewById(R.id.longitude);
        altitudeTV = (TextView) findViewById(R.id.altitude);
        locationNameTV = (TextView) findViewById(R.id.locationName);

        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

        if (checkSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            return;
        }

        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 5000, 0, locationListener);

        location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

        onLocationChanged(location);

        LocationListener locationListener = new LocationListener() {
            @Override
            public void onLocationChanged(Location location) {
                longitude = location.getLongitude();
                latitude = location.getLatitude();
                altitude = location.getAltitude();
                locationName = "Placeholder";

                longitudeTV.setText("Longitude: \n" + longitude + "°");
                latitudeTV.setText("Latitude: \n" + latitude + "°");
                altitudeTV.setText("Altitude: \n" + altitude + "m");
                locationNameTV.setText("Location: \n" + locationName);
            }

            @Override
            public void onStatusChanged(String s, int i, Bundle bundle) {

            }

            @Override
            public void onProviderEnabled(String s) {

            }

            @Override
            public void onProviderDisabled(String s) {

            }
        };
    }
}

我不确定这是一个语法问题还是一个范围问题，但我不断遇到“无法解决符号”错误。这就像我没有实现

LocationListener

方法一样。我尝试将

implements LocationListener

添加到

MainActivity

中，结果显示一个错误，表明我没有实现

LocationListener

方法。我不确定我的错误在哪里

编辑：

我已经根据你的答案更改了密码。当我尝试实现

//locationManager.RequestLocationUpdate（Context.LOCATION\u服务，5000，0，this）时我在尝试启动应用程序时得到以下信息：
LocationTestApp一直停止
。我已经把这句话注释掉了，这个应用程序又能正常工作了

public class MainActivity extends AppCompatActivity implements LocationListener {

    TextView latitudeTV;
    TextView longitudeTV;
    TextView altitudeTV;
    double latitude;
    double longitude;
    double altitude;

    LocationManager locationManager;

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

        latitudeTV = (TextView) findViewById(R.id.latitude);
        longitudeTV = (TextView) findViewById(R.id.longitude);
        altitudeTV = (TextView) findViewById(R.id.altitude);

        locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

        if (checkSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            return;
        }

        //locationManager.requestLocationUpdates(Context.LOCATION_SERVICE, 5000, 0, this);

        Location location = locationManager.getLastKnownLocation(locationManager.NETWORK_PROVIDER);

        onLocationChanged(location);

    }

    @Override
    public void onLocationChanged(Location location) {
        longitude = location.getLongitude();
        latitude = location.getLatitude();
        altitude = location.getAltitude();

        longitudeTV.setText("Longitude: \n" + longitude + "°");
        latitudeTV.setText("Latitude: \n" + latitude + "°");
        altitudeTV.setText("Altitude: \n" + altitude + "m");
    }

    @Override
    public void onStatusChanged(String s, int i, Bundle bundle) {

    }

    @Override
    public void onProviderEnabled(String s) {

    }

    @Override
    public void onProviderDisabled(String s) {

    }
}

LocationListener
类（在本例中为活动）应定义如下：

import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;

public class MainActivity extends AppCompatActivity implements LocationListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ...
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 5000, 0, this);  // Note: You pass this, so the overridden methods
    }

    @Override
    public void onLocationChanged(Location location) {
        // Do your stuff here
    }


    @Override
    public void onProviderDisabled(String provider) {}

    @Override
    public void onProviderEnabled(String provider) {}

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

这就是jle评论中的解决方案

但是，如果要使用在onCreate中声明的
locationListener
，则应在使用它之前声明它，方法如下：

...onCreate(...) {
    ...
    LocationListener locationListener = new LocationListener() {...} // Define this...

    locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 5000, 0, locationListener);   // ...and then call this

    location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

    onLocationChanged(location); 
}

实现接口时，需要实现方法。再次将其添加为MainActivity的接口，然后自动生成方法。修改行如下：
公共类MainActivity扩展AppCompatActivity实现LocationListener
，然后单击该行。然后按Alt+Enter并转到“实现方法”。添加它们，那么你就不会因为没有实现它们而出错。我已经按照你的答案编辑了我的代码，现在我的应用程序在启动时崩溃了。有关代码，请参阅我编辑的问题。请检查您的日志中是否有错误，“LocationTestApp持续停止”应该有动机，在您的日志中写有类似“由…”的内容。在我的
requestLocationUpdates
调用中似乎缺少提供程序。相反，我添加了这些代码行
Criteria=newcriteria（）
标准.设置精度（标准.精度\u罚款）
String provider=locationManager.getBestProvider（标准，true）locationManager.requestLocationUpdates（provider，5000，0，this）调用更新时，它完全按照预期工作