Java 此行“Plus.PeopleApi.getCurrentPerson（myClient）！=null”为什么返回null？

我对这个源代码有一个问题，可能清单文件中的权限是可以的，我用生成的指纹SHA1在Google开发者控制台中创建了一个ClientID。有人知道为什么返回带null结果的Plus.PeopleApi.GetCurrentPersonCyclient吗

package com.getgender;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesClient.ConnectionCallbacks;
import com.google.android.gms.common.Scopes;

import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.api.ResultCallback;

import com.google.android.gms.plus.People;
import com.google.android.gms.plus.People.LoadPeopleResult;
import com.google.android.gms.plus.Plus;
import com.google.android.gms.plus.PlusClient;
import com.google.android.gms.plus.model.people.Person;

import android.app.Activity;
import android.content.IntentSender.SendIntentException;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;

public class MainActivity extends Activity
        implements
        com.google.android.gms.common.api.GoogleApiClient.ConnectionCallbacks,
        com.google.android.gms.common.api.GoogleApiClient.OnConnectionFailedListener, ConnectionCallbacks, ResultCallback<LoadPeopleResult> {

    private static final int RC_SIGN_IN = 0;
    private GoogleApiClient myClient;
    private boolean mIntentInProgress;

    private PlusClient mPlusClient;


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

        myClient = new GoogleApiClient.Builder(this).addApi(Plus.API)
                .addScope(Plus.SCOPE_PLUS_PROFILE).addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this).build();

        // myClient.connect();
     //plusClient = new PlusClient.Builder(this, this, this).setScopes(Scopes.PROFILE, Scopes.PLUS_ME ,"https://www.googleapis.com/auth/userinfo.email").build();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onConnectionFailed(ConnectionResult result) {

        Toast.makeText(getApplicationContext(), "Connection failed",
                Toast.LENGTH_SHORT).show();
        if (!mIntentInProgress && result.hasResolution()) {
            try {
                mIntentInProgress = true;
                result.startResolutionForResult(this, RC_SIGN_IN);
            } catch (SendIntentException e) {
                // The intent was canceled before it was sent. Return to the
                // default
                // state and attempt to connect to get an updated
                // ConnectionResult.
                mIntentInProgress = false;
                myClient.connect();
            }
        }

    }

    @Override
    public void onConnected(Bundle arg0) {
        // TODO Auto-generated method stub
        // Toast.makeText(getApplicationContext(), "Connected",
        // Toast.LENGTH_SHORT).show();

        String name = Plus.AccountApi.getAccountName(myClient);
        Toast.makeText(getApplicationContext(), name,
                Toast.LENGTH_SHORT).show();


         Plus.PeopleApi.loadVisible(myClient, null).setResultCallback(this);

            // After that  fetch data 
            if (Plus.PeopleApi.getCurrentPerson(myClient) != null) {
                    Person currentPerson = Plus.PeopleApi
                            .getCurrentPerson(myClient);

                    String personName = currentPerson.getDisplayName();

        String currentPerson2 = Plus.AccountApi.getAccountName(myClient);
        Toast.makeText(getApplicationContext(), personName,
                Toast.LENGTH_SHORT).show();
            }

//      int a = plusClient.getCurrentPerson().getGender();
//      Toast.makeText(getApplicationContext(), a, Toast.LENGTH_SHORT).show();

        // People g = Plus.PeopleApi.getCurrentPerson(myClient);
        // Person p = Plus.PeopleApi.getCurrentPerson(myClient);
        // String a = p.getBirthday();

        //Plus.PeopleApi.

        if (Plus.PeopleApi.getCurrentPerson(myClient) != null) {

        Toast.makeText(getApplicationContext(), "nem null", Toast.LENGTH_SHORT).show();
        // getData();
        }else{
            Toast.makeText(getApplicationContext(), "null", Toast.LENGTH_SHORT).show();
        }

        // int a = Plus.PeopleApi.getCurrentPerson(myClient).getGender();
        // Toast.makeText(getApplicationContext(), a,
        // Toast.LENGTH_SHORT).show();

        // try {
        // if (Plus.PeopleApi.getCurrentPerson(myClient) != null) {
        // Person currentPerson = Plus.PeopleApi
        // .getCurrentPerson(myClient);
        // String personName = currentPerson.getDisplayName();
        // // String personPhotoUrl = currentPerson.getImage().getUrl();
        // // String personGooglePlusProfile = currentPerson.getUrl();
        // // String email = Plus.AccountApi.getAccountName(myClient);
        // int a = currentPerson.getGender();
        //
        // Toast.makeText(getApplicationContext(), personName,
        // Toast.LENGTH_SHORT).show();
        //
        //
        //
        // } else {
        // Toast.makeText(getApplicationContext(),
        // "Person information is null", Toast.LENGTH_LONG).show();
        // }
        // } catch (Exception e) {
        // e.printStackTrace();
        // }
    }

    // public void getData(){
    // Person currentPerson = Plus.PeopleApi.getCurrentPerson(myClient);
    // String curr = currentPerson.getDisplayName();
    // Toast.makeText(getApplicationContext(), curr, Toast.LENGTH_SHORT).show();
    // }

    @Override
    public void onConnectionSuspended(int arg0) {
        Toast.makeText(getApplicationContext(), "Connection suspended",
                Toast.LENGTH_SHORT).show();
        // TODO Auto-generated method stub
        myClient.connect();
    }

    @Override
    protected void onStart() {
        super.onStart();

        Toast.makeText(getApplicationContext(), "onStart", Toast.LENGTH_SHORT)
                .show();

        myClient.connect();
    }

    @Override
    public void onDisconnected() {
        // TODO Auto-generated method stub

    }

    @Override
    public void onResult(LoadPeopleResult arg0) {
        // TODO Auto-generated method stub

    }

}