从最后知道的位置Android Studio获取Long / Lat

Question

    package com.example.sander.app;

import android.app.Fragment;
import android.location.Location;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationServices;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by Sander on 6-4-2017.
 */

public class BlankFragment extends Fragment implements GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener{
    public BlankFragment() {
        // Required empty public constructor
    }
    GoogleApiClient mGoogleApiClient;
    Location mLastLocation;
    TextView mLatitudeText;
    TextView mLongitudeText;
    @Override
    public void onCreate(Bundle bundle){
        mGoogleApiClient = new GoogleApiClient.Builder(getActivity())
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();
        super.onCreate(bundle);
    }

    @Override
    public void onConnectionFailed(ConnectionResult result) {
    }
    @Override
    public void onStart(){
        mGoogleApiClient.connect();
        super.onStart();
    }
    @Override
    public void onStop(){
        mGoogleApiClient.disconnect();
        super.onStop();
    }
    @Override
    public void onConnectionSuspended(int arg0) {
    }

    @Override
    public void onConnected(Bundle connectionHint) {
        mLastLocation = LocationServices.FusedLocationApi.getLastLocation(
                mGoogleApiClient);
        if (mLastLocation != null) {
            mLatitudeText.setText(String.valueOf(mLastLocation.getLatitude()));
            //mLongitudeText.setText(String.valueOf(mLastLocation.getLongitude()));
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
            View view = inflater.inflate(R.layout.fragment_blank, container, false);
            final TextView txt=  (TextView)view.findViewById(R.id.onzin);
            //txt.setText(String.valueOf(mLastLocation.getLatitude()));
            // Inflate the layout for this fragment
            return  view;
        }
    }

ANDROIDMANIFEST

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

    <uses-sdk
        android:minSdkVersion="17"
        android:targetSdkVersion="17" />

    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <meta-data
            android:name="com.google.android.geo.API_KEY"
            android:value="@string/google_maps_key" />
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name"
            android:theme="@style/AppTheme.NoActionBar"
            android:configChanges="orientation|screenSize|keyboardHidden">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".SettingsActivity"
            android:label="@string/title_activity_settings"></activity>
    </application>

</manifest>

LOGCAT

Process: com.example.sander.app, PID: 22804
                                                                        java.lang.NullPointerException: Attempt to invoke virtual method 'double android.location.Location.getLatitude()' on a null object reference
                                                                            at com.example.sander.app.BlankFragment.onCreateView(BlankFragment.java:85)
                                                                            at android.app.Fragment.performCreateView(Fragment.java:2353)
                                                                            at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:995)
                                                                            at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1171)
                                                                            at android.app.BackStackRecord.run(BackStackRecord.java:816)
                                                                            at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1578)
                                                                            at android.app.FragmentManagerImpl$1.run(FragmentManager.java:483)
                                                                            at android.os.Handler.handleCallback(Handler.java:751)
                                                                            at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                            at android.os.Looper.loop(Looper.java:154)
                                                                            at android.app.ActivityThread.main(ActivityThread.java:6119)
                                                                            at java.lang.reflect.Method.invoke(Native Method)
                                                                            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
                                                                            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

这是我到目前为止的代码，当我启动“Graph”标签时，应用程序崩溃了。我不知道我做错了什么可以帮助我解决这个问题。我想要的是获得Long＆amp;从我上次知道的位置拉出来。