Android 6.0位置權限

Question

我正在嘗試實現位置的運行時權限。實現如下：

public class MyLocationManager implements android.location.LocationListener, ActivityCompat.OnRequestPermissionsResultCallback { 

    private static LocationManager m_locationManager; 
    private static final int REQUEST_COARSE_LOCATION = 999; 
    private static final int REQUEST_FINE_LOCATION = 998; 

    private String provider; 
    private Context mContext; 

    public void startListenLocation(Context context) { 

     this.mContext = context; 
     m_locationManager = (LocationManager) mContext.getSystemService(Context.LOCATION_SERVICE); 

     ... 

     if (Build.VERSION.SDK_INT >= 23 && ((ContextCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_COARSE_LOCATION)) != PackageManager.PERMISSION_GRANTED)) { 
      ActivityCompat.requestPermissions((Activity) mContext, new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, REQUEST_COARSE_LOCATION) ; 
     } else { 
      Location location = m_locationManager.getLastKnownLocation(provider); 
     } 

     ... 
    } 

    @Override 
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { 
     switch (requestCode) { 
      case REQUEST_COARSE_LOCATION: { 

       if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){ 
        //compiler error on the following line 
        Location myLocation = m_locationManager.getLastKnownLocation(provider); 
       } else { 
        //Permission denied 
       } 
       return; 
      } 
     } 
    } 
} 

我得到一個語法錯誤，當我在onRequestPermissionResult()打電話getLastKnownLocation()。它告訴我再次檢查許可，即使我已經這樣做了。因此，誰能告訴什麼是錯我的執行這裏

Answer 1

方法getLastKnownLocation標註有：

@RequiresPermission(anyOf = {ACCESS_COARSE_LOCATION, ACCESS_FINE_LOCATION}) 

因爲這個原因，你得到警告：

呼叫要求可能被拒絕的權限用戶：代碼應明確檢查，看是否許可可用（用的checkPermission）或明確處理潛在拋出：SecurityException

你有兩個選擇，以避免該警告：

1. 通話getLastKnownLocation前添加評論：

   @Override 
   public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { 
       switch (requestCode) { 
        case REQUEST_COARSE_LOCATION: 
        { 
         if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){ 
          //noinspection ResourceType 
          Location myLocation = m_locationManager.getLastKnownLocation(provider); 
         } else { 
          //Permission denied 
         } 
         return; 
        } 
       } 
   } 
   

2. 重構代碼，添加一個方法getLastKnownLocationIfAllowed：

   public void startListenLocation(Context context) { 
   
       this.mContext = context; 
       m_locationManager = (LocationManager) mContext.getSystemService(Context.LOCATION_SERVICE); 
   
       if (!getLastKnownLocationIfAllowed()) 
        ActivityCompat.requestPermissions((Activity) mContext, new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, REQUEST_COARSE_LOCATION); 
   } 
   
   private boolean getLastKnownLocationIfAllowed() { 
       if (ContextCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED) { 
        Location location = m_locationManager.getLastKnownLocation(provider); 
        return true; 
       } 
   
       return false; 
   } 
   

   在你的活動中：

   @Override 
   public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) { 
       switch (requestCode) { 
        case REQUEST_COARSE_LOCATION: { 
         if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { 
          myLocationManager.getLastKnownLocationIfAllowed(); 
         } else { 
          //Permission denied 
         } 
         return; 
        } 
       } 
   }