日志不显示位置数据

Question

我正在上一门 Android 课程，我们在其中学习如何获取位置数据。跟着导师，我想我完全按照他说的做了这个应用程序，尽管我的 Android Monitor 中没有任何位置数据。

我使用的是 Android Studio 2.3.3，并在华为 p10 lite 上运行该应用。

代码看起来像这样，其实很基本：

public class MainActivity extends AppCompatActivity {

LocationManager locationManager;

LocationListener locationListener;

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);

    if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED)

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

    }

}

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

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

    locationListener = new LocationListener() {

        @Override
        public void onLocationChanged(Location location) {

            Log.i("Location", location.toString());

        }

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

        }

        @Override
        public void onProviderEnabled(String s) {

        }

        @Override
        public void onProviderDisabled(String s) {

        }

    };

    // If device is running SDK < 23

    if (Build.VERSION.SDK_INT < 23) {

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

    } else {

        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {

            // ask for permission

            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 1);


        } else {

            // we have permission!

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

        }

    }

}

}

清单：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.robpercival.locationdemo">

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

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

</manifest>

Answer 1

这与日志无关。这与您请求许可的方式有关

1. 使用状态码请求许可。在您的情况下，您使用 1 作为状态码。

   ActivityCompat.requestPermissions(thisActivity, 新字符串[]{Manifest.permission.READ_CONTACTS}, MY_PERMISSIONS_REQUEST_READ_CONTACTS);

2. 根据请求代码处理结果。您没有正确执行此操作。所以你永远不会收到onLocationChanged 的回调。

   @Override public void onRequestPermissionsResult(int requestCode,
           String permissions[], int[] grantResults) {
       switch (requestCode) {
           case MY_PERMISSIONS_REQUEST_READ_CONTACTS: {
               // If request is cancelled, the result arrays are empty.
               if (grantResults.length > 0
                   && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                   // permission was granted, yay! Do the
                   // contacts-related task you need to do.
               } else {
                   // permission denied, boo! Disable the
                   // functionality that depends on this permission.
               }
               return;
           }
   
           // other 'case' lines to check for other
           // permissions this app might request.
       } 
   

   }

更详细的解释请参考https://developer.android.com/training/permissions/requesting#java