在调用getCredentialAsync()方法时出现NoCredentialException的原因可能是因为未能正确配置和使用androidx凭据管理器PASSKEYS。以下是一个解决方法的示例代码：

import androidx.security.identity.Credential;
import androidx.security.identity.CryptoObject;
import androidx.security.identity.IdentityCredential;
import androidx.security.identity.NoCredentialException;
import androidx.security.identity.PersonalizationData;
import androidx.security.identity.ResultData;

import java.util.concurrent.Executor;

public class MainActivity extends AppCompatActivity {

    private static final String CREDENTIAL_NAME = "my_credential";
    private IdentityCredential identityCredential;
    private Executor executor;

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

        // 初始化IdentityCredential对象和Executor对象
        identityCredential = IdentityCredential.getInstance(CREDENTIAL_NAME, this);
        executor = new Executor() {
            @Override
            public void execute(Runnable runnable) {
                new Thread(runnable).start();
            }
        };

        // 调用getCredentialAsync()方法
        identityCredential.getCredentialAsync(new PersonalizationData(), executor,
                new IdentityCredential.CredentialCallback() {
                    @Override
                    public void onCredentialRetrieved(ResultData resultData) {
                        // 处理获取到的凭据数据
                    }

                    @Override
                    public void onCredentialError(NoCredentialException e) {
                        // 处理获取凭据时出现的错误
                    }
                });
    }
}

请确保在AndroidManifest.xml文件中正确配置了IdentityCredentialService的权限和服务：

    

    

        
            
                
            
        
        
        ...
    

确保在build.gradle文件中添加了IdentityCredential库的依赖：

implementation 'androidx.security:security-identity:1.0.0-alpha02'

以上示例代码演示了如何正确使用androidx凭据管理器PASSKEYS的getCredentialAsync()方法，并处理可能出现的NoCredentialException异常。请根据实际需求进行修改和调整。