Google LocationServices: Location not being shown in the textView

Question

I have a simple application with only one activity and the goal is to display the location in a TextView. This is my MainActivity:

package com.example.android.gpsapp;

import android.content.pm.PackageManager;
import android.location.Location;
import android.os.Bundle;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.TextView;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;

public class MainActivity extends AppCompatActivity implements GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener, LocationListener {


    private final String LOG_TAG ="GPSApp";
    private TextView txtOutput;
    private GoogleApiClient mGoogleApiClient;
    private LocationRequest mLocationRequest;
    private static final int REQUEST_CODE_LOCATION = 2;

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

        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addApi(LocationServices.API)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .build();

        txtOutput = (TextView) findViewById(R.id.txtOutput);
    }


    @Override
    protected void onStart() {
        super.onStart();
        // Connect the client.
        mGoogleApiClient.connect();
    }

    @Override
    protected void onStop() {
        // Disconnecting the client invalidates it.
        mGoogleApiClient.disconnect();
        super.onStop();
    }

    @Override
    public void onConnected(Bundle bundle) {

        mLocationRequest = LocationRequest.create();
        mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
        mLocationRequest.setInterval(1000); // Update location every second

        if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION)
                != PackageManager.PERMISSION_GRANTED) {
            // Request missing location permission.
            ActivityCompat.requestPermissions(this,
                    new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION},
                    REQUEST_CODE_LOCATION);
        } else {
            // Location permission has been granted, continue as usual.
            LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
        }
    }

    @Override
    public void onConnectionSuspended(int i) {
        Log.i(LOG_TAG, "GoogleApiClient connection has been suspended");
    }

    @Override
    public void onConnectionFailed(ConnectionResult connectionResult) {
        Log.i(LOG_TAG, "GoogleApiClient connection has failed");
    }

    @Override
    public void onLocationChanged(Location location) {
        Log.i(LOG_TAG, location.toString());

        txtOutput.setText(Double.toString(location.getLatitude()));
    }
}

This is my Manifest file:

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

    <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.gms.version"
            android:value="@integer/google_play_services_version"/>
        <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" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

</manifest>

Unfortunately, the location is not being shown in the textView, like I need it to. Let me know if you need any more info pertaining this. Just remember that I'm using Google API location services, and not Android's built-in location stuff. I'm not getting any errors or log messages, so I really don't know what's wrong. Please help...Thanks!