使用 fusedLocationProvider.removeLocationUpdates (locationCallback) Android Studio 时出错

Posted 2023-04-14

【中文标题】使用 fusedLocationProvider.removeLocationUpdates (locationCallback) Android Studio 时出错

【英文标题】：Error when using fusedLocationProvider.removeLocationUpdates (locationCallback) Android Studio

【发布时间】：2021-04-13 08:37:50

【问题描述】：

我正在编写一个代码来捕获用户的当前位置并在准确的时刻跟踪 GPS 坐标。

我正在使用 2 个按钮，一个是用于开始录制的“RecordButton”按钮，此时 gps 跟踪也已启动。

以及用于停止所有跟踪的 StopButton 按钮。只有当stopButton被按下时，app仍然会发送坐标并且不会停止发送。

已经尝试使用

fusedLocationProviderClient.removeLocationUpdates(locationCallback);在 StopRecordButton 侦听器中。

如果有人能帮助我，我将不胜感激。

我的代码：

cameraActionButton.setOnClickListener(new OnClickListener() 

                @Override
                public void onClick(View v)    //Botão de Gravação do App; (Record button Action)

                    final HHConfigTCPClient hhudpClient = new HHConfigTCPClient(prefs.getString("prefServerIp", ""),
                            8085);

                    final boolean _paused = state.isPaused();


                    switch (cameraAction) 
                        case RECORD:
                            //Uma thread para rodar a localização
                            new Thread(new Runnable() 
                                @Override
                                public void run() 
                                    MjpegFragment.this.getActivity().runOnUiThread(new Runnable() 
                                        @Override
                                        public void run() 

                                            fusedLocationProviderClient = new FusedLocationProviderClient(getActivity());
                                            locationRequest = new LocationRequest();
                                            locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
                                            locationRequest.setFastestInterval(4000);
                                            locationRequest.setInterval(2000);
                                            if (ActivityCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_FINE_LOCATION)
                                                    != PackageManager.PERMISSION_GRANTED &&
                                                    ActivityCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_COARSE_LOCATION)
                                                            != PackageManager.PERMISSION_GRANTED) 
                                                return;
                                            
                                            fusedLocationProviderClient.requestLocationUpdates(locationRequest, new LocationCallback() 
                                                @Override
                                                public void onLocationResult(final LocationResult locationResult) 
                                                    super.onLocationResult(locationResult);
                                                    t.scheduleAtFixedRate(mTimerTask = new TimerTask() 
                                                        public void run() 
                                                            hhudpClient.set(HHConfigTCPClient.PROPERTY.LATITUDE, locationResult.getLastLocation().getLatitude());
                                                            state.setLatitude(locationResult.getLastLocation().getLatitude());
                                                            hhudpClient.set(HHConfigTCPClient.PROPERTY.LONGITUDE, locationResult.getLastLocation().getLongitude());
                                                            state.setLongitude(locationResult.getLastLocation().getLongitude());
                                                        
                                                    , 4000, 2000);
                                                
                                            , Looper.getMainLooper());


                                        
                                    );
                                

                            ).start(); 


stopRecordButton.setOnClickListener(new OnClickListener() 
                @Override
                public void onClick(View v) 

                    final HHConfigTCPClient hhudpClient = new HHConfigTCPClient(prefs.getString("prefServerIp", ""),
                            8085);


                    new Thread(new Runnable() 
                        @Override
                        public void run() 

                            HHConfigTCPClient hhudpClient = new HHConfigTCPClient(prefs.getString("prefServerIp", ""),
                                    8085);

                            final double timestamp = System.currentTimeMillis();


                            if (hhudpClient.set(HHConfigTCPClient.PROPERTY.RECORD, 0.0, timestamp)) 
                                fusedLocationProviderClient.removeLocationUpdates(locationCallback);


                             else 
                                MjpegFragment.this.getActivity().runOnUiThread(new Runnable() 
                                    @Override
                                    public void run() 
                                        showToast("Falha de Comunicação: comando stop.");
                                    
                                );
                            


                        
                    

                    ).start();
                
            );

【参考方案1】：

This error appears on my android Studio:

E/AndroidRuntime: FATAL EXCEPTION: Thread-7
    Process: br.com.visit.hammerhead2, PID: 15224
    java.lang.NullPointerException: Listener must not be null
        at com.google.android.gms.common.internal.Preconditions.checkNotNull(Unknown Source:9)
        at com.google.android.gms.common.api.internal.ListenerHolders.createListenerKey(Unknown Source:2)
        at com.google.android.gms.location.FusedLocationProviderClient.removeLocationUpdates(Unknown Source:6)
        at br.com.visit.hammerhead2.fragments.MjpegFragment$6$1.run(MjpegFragment.java:718)
        at java.lang.Thread.run(Thread.java:919)