GoogleSignInAccount不能为空

Question

我正在尝试通过游戏服务在我的游戏商店里实现我的游戏的领导板。

我很难实现这一点。我不是专家。我将补充说，游戏是用HTML，CSS，javascript。我已经在控制台中生成了主板ID。我无法解决以下错误：

我忘记补充说，这个游戏目前正在通过Android studio调试器通过一部连接到USB计算机的电话进行测试。

错误：

java.lang.RuntimeException: Unable to start activity
ComponentInfo{com.example.pudzibreak/com.example.pudzibreak.MainActivity}:
java.lang.NullPointerException: GoogleSignInAccount must not be null

MainActivity

package com.example.pudzibreak;

import android.content.Intent;
import android.os.Bundle;

import android.view.View;

import android.webkit.WebView;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;

import com.google.android.gms.auth.api.Auth;
import com.google.android.gms.auth.api.signin.GoogleSignIn;
import com.google.android.gms.auth.api.signin.GoogleSignInAccount;
import com.google.android.gms.auth.api.signin.GoogleSignInClient;
import com.google.android.gms.auth.api.signin.GoogleSignInOptions;
import com.google.android.gms.auth.api.signin.GoogleSignInResult;
import com.google.android.gms.games.Games;
import com.google.android.gms.games.LeaderboardsClient;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;
 import com.google.android.gms.common.SignInButton;


public class MainActivity extends AppCompatActivity implements View.OnClickListener {


    private static final String TAG = "XD";

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

        SignInButton signInButton = findViewById(R.id.sign_in_button);
        signInButton.setSize(SignInButton.SIZE_STANDARD);

           findViewById(R.id.sign_in_button).setOnClickListener(this);

        WebView WebView= (WebView) findViewById(R.id.webView);
        WebView.getSettings().setJavaScriptEnabled(true);

        WebView.loadUrl("file:///android_asset/myHtml.html");

       signInSilently();
      Games.getLeaderboardsClient(this, GoogleSignIn.getLastSignedInAccount(this));
    }
    private void signInSilently(){
        GoogleSignInOptions signInOptions = GoogleSignInOptions.DEFAULT_GAMES_SIGN_IN;
        GoogleSignInAccount account = GoogleSignIn.getLastSignedInAccount(this);
        if (GoogleSignIn.hasPermissions(account, signInOptions.getScopeArray())) {

            GoogleSignInAccount signedInAccount = account;

        } else {

            GoogleSignInClient signInClient = GoogleSignIn.getClient(this, signInOptions);
            signInClient
                    .silentSignIn()
                    .addOnCompleteListener(
                            this,
                            new OnCompleteListener<GoogleSignInAccount>() {
                                @Override
                                public void onComplete(@NonNull Task<GoogleSignInAccount> task) {
                                    if (task.isSuccessful()) {

                                        GoogleSignInAccount signedInAccount = task.getResult();


                                    } else {
                // do something
                                    }
                                }
                            });
        }

    }

    @Override
    public void onClick(View view) {
        if (view.getId() == R.id.sign_in_button) {
            startSignInIntent();


        }
    }

    private static final int RC_LEADERBOARD_UI = 9004;

    private void showLeaderboard() {
        Games.getLeaderboardsClient(this, GoogleSignIn.getLastSignedInAccount(this))
                .getLeaderboardIntent("XXXXXXXXXXXXXXX")
                .addOnSuccessListener(new OnSuccessListener<Intent>() {
                    @Override
                    public void onSuccess(Intent intent) {
                        startActivityForResult(intent, RC_LEADERBOARD_UI);
                    }
                });
    }



    private static final int RC_SIGN_IN = 900;

    private void startSignInIntent() {
        GoogleSignInClient signInClient = GoogleSignIn.getClient(this,
                GoogleSignInOptions.DEFAULT_GAMES_SIGN_IN);
        Intent intent = signInClient.getSignInIntent();
        startActivityForResult(intent, RC_SIGN_IN);

    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == RC_SIGN_IN) {
            GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(data);
            if (result.isSuccess()) {
                // The signed in account is stored in the result.
                GoogleSignInAccount signedInAccount = result.getSignInAccount();
            } else {
                String message = result.getStatus().getStatusMessage();
                if (message == null || message.isEmpty()) {
                    message = "XXX";
                }
                new AlertDialog.Builder(this).setMessage(message)
                        .setNeutralButton(android.R.string.ok, null).show();
            }
        }
        showLeaderboard();
    }



};

Answer 1

Games.getLeaderboardsClient(this, GoogleSignIn.getLastSignedInAccount(this));

在onCreate中调用并导致您的崩溃。

GoogleSignIn.getLastSignedInAccount(this)返回null。

如果没有“最后登录”，则必须返回null。

你可以试试这个：

GoogleSignInAccount account = GoogleSignIn.getLastSignedInAccount(this)
if(account != null) {
    Log.d("TUT", "getting leaderboard client");
    Games.getLeaderboardsClient(this, account);
} else {
    Log.e("TUT", "no last sign in. Not getting leaderboard client.");
}