Await must not be called on the UI thread when time is greater than zero

Question

I am trying to use the fitness api for displaying last week's data on android but getting the following error:

E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.admin.safely_counter, PID: 7435 java.lang.IllegalStateException: await must not be called on the UI thread when time is greater than zero. at com.google.android.gms.common.internal.Preconditions.checkNotMainThread(Unknown Source) at com.google.android.gms.common.api.internal.BasePendingResult.await(Unknown Source) at com.example.admin.safely_counter.MainActivity.displayLastWeeksData(MainActivity.java:99) at com.example.admin.safely_counter.MainActivity.onConnected(MainActivity.java:149) at com.google.android.gms.common.internal.GmsClientEventManager.onConnectionSuccess(Unknown Source) at com.google.android.gms.common.api.internal.zzav.zzb(Unknown Source) at com.google.android.gms.common.api.internal.zzaj.zzat(Unknown Source) at com.google.android.gms.common.api.internal.zzaj.onConnected(Unknown Source) at com.google.android.gms.common.api.internal.zzbd.onConnected(Unknown Source) at com.google.android.gms.common.api.internal.zzp.onConnected(Unknown Source) at com.google.android.gms.common.internal.zzf.onConnected(Unknown Source) at com.google.android.gms.common.internal.BaseGmsClient$PostInitCallback.handleServiceSuccess(Unknown Source) at com.google.android.gms.common.internal.BaseGmsClient$zza.deliverCallback(Unknown Source) at com.google.android.gms.common.internal.BaseGmsClient$zza.deliverCallback(Unknown Source) at com.google.android.gms.common.internal.BaseGmsClient$CallbackProxy.deliverCallback(Unknown Source) at com.google.android.gms.common.internal.BaseGmsClient$zzb.handleMessage(Unknown Source) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:6123) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:757)

MainActivity.java

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

    private Button mButtonViewWeek;
    private Button mButtonViewToday;
    private Button mButtonAddSteps;
    private Button mButtonUpdateSteps;
    private Button mButtonDeleteSteps;

    private GoogleApiClient mGoogleApiClient;

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

        mButtonViewWeek = (Button) findViewById(R.id.btn_view_week);
        mButtonViewToday = (Button) findViewById(R.id.btn_view_today);
        mButtonAddSteps = (Button) findViewById(R.id.btn_add_steps);
        mButtonUpdateSteps = (Button) findViewById(R.id.btn_update_steps);
        mButtonDeleteSteps = (Button) findViewById(R.id.btn_delete_steps);

        mButtonViewWeek.setOnClickListener(this);
        mButtonViewToday.setOnClickListener(this);
        mButtonAddSteps.setOnClickListener(this);
        mButtonUpdateSteps.setOnClickListener(this);
        mButtonDeleteSteps.setOnClickListener(this);

        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addApi(Fitness.HISTORY_API)
                .addScope(new Scope(Scopes.FITNESS_ACTIVITY_READ_WRITE))
                .addConnectionCallbacks(this)
                .enableAutoManage(this, 0, this)
                .build();
    }

    private class ViewWeekStepCountTask extends AsyncTask<Void, Void, Void> {
        protected Void doInBackground(Void... params) {
            displayLastWeeksData();
            return null;
        }
    }

    public void displayLastWeeksData(){
        Calendar cal = Calendar.getInstance();
        Date now = new Date();
        cal.setTime(now);
        long endTime = cal.getTimeInMillis();
        cal.add(Calendar.WEEK_OF_YEAR, -1);
        long startTime = cal.getTimeInMillis();

        java.text.DateFormat dateFormat = DateFormat.getDateInstance();
        Log.e("History", "Range Start: " + dateFormat.format(startTime));
        Log.e("History", "Range End: " + dateFormat.format(endTime));

//Check how many steps were walked and recorded in the last 7 days
        final DataReadRequest readRequest = new DataReadRequest.Builder()
                .aggregate(DataType.TYPE_STEP_COUNT_DELTA, DataType.AGGREGATE_STEP_COUNT_DELTA)
                .bucketByTime(1, TimeUnit.DAYS)
                .setTimeRange(startTime, endTime, TimeUnit.MILLISECONDS)
                .build();

        final DataReadResult dataReadResult = Fitness.HistoryApi.readData(mGoogleApiClient, readRequest).await(1,TimeUnit.MINUTES);
//Used for aggregated data
        if (dataReadResult.getBuckets().size() > 0) {
            Log.e("History", "Number of buckets: " + dataReadResult.getBuckets().size());
            for (Bucket bucket : dataReadResult.getBuckets()) {
                List<DataSet> dataSets = bucket.getDataSets();
                for (DataSet dataSet : dataSets) {
                    showDataSet(dataSet);
                }
            }
        }
//Used for non-aggregated data
        else if (dataReadResult.getDataSets().size() > 0) {
            Log.e("History", "Number of returned DataSets: " + dataReadResult.getDataSets().size());
            for (DataSet dataSet : dataReadResult.getDataSets()) {
                showDataSet(dataSet);
            }
        }

    }

    private void showDataSet(DataSet dataSet) {
        Log.e("History", "Data returned for Data type: " + dataSet.getDataType().getName());
        DateFormat dateFormat = DateFormat.getDateInstance();
        DateFormat timeFormat = DateFormat.getTimeInstance();

        for (DataPoint dp : dataSet.getDataPoints()) {
            Log.e("History", "Data point:");
            Log.e("History", "\tType: " + dp.getDataType().getName());
            Log.e("History", "\tStart: " + dateFormat.format(dp.getStartTime(TimeUnit.MILLISECONDS)) + " " + timeFormat.format(dp.getStartTime(TimeUnit.MILLISECONDS)));
            Log.e("History", "\tEnd: " + dateFormat.format(dp.getEndTime(TimeUnit.MILLISECONDS)) + " " + timeFormat.format(dp.getStartTime(TimeUnit.MILLISECONDS)));
            for(Field field : dp.getDataType().getFields()) {
                Log.e("History", "\tField: " + field.getName() +
                        " Value: " + dp.getValue(field));
            }
        }
    }

    @Override
    public void onConnectionSuspended(int i) {
        Log.e("HistoryAPI", "onConnectionSuspended");
    }

    @Override
    public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
        Log.e("HistoryAPI", "onConnectionFailed");
    }
@Override
    public void onConnected(@Nullable Bundle bundle) {
        Log.e("HistoryAPI", "onConnected");
        displayLastWeeksData();
    }


    @Override
    public void onClick(View v) {
    }
}