在Android中使用OkHttp3进行网络请求时，如果遇到客户端证书错误，可以通过以下代码示例解决：

1. 创建一个自定义的TrustManager，用于验证服务器证书：

import javax.net.ssl.X509TrustManager;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

public class CustomTrustManager implements X509TrustManager {
    @Override
    public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        // 不验证客户端证书
    }

    @Override
    public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        // 验证服务器证书
        // 如果服务器证书不合法，可以抛出CertificateException
    }

    @Override
    public X509Certificate[] getAcceptedIssuers() {
        return new X509Certificate[0];
    }
}

2. 创建一个自定义的SSLContext，将自定义的TrustManager与默认的KeyManager绑定：

import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.X509TrustManager;
import java.security.KeyManagementException;
import java.security.NoSuchAlgorithmException;

public class CustomSSLContext {
    public static SSLSocketFactory getSocketFactory() {
        try {
            SSLContext sslContext = SSLContext.getInstance("TLS");
            X509TrustManager trustManager = new CustomTrustManager();
            sslContext.init(null, new X509TrustManager[]{trustManager}, null);
            return sslContext.getSocketFactory();
        } catch (NoSuchAlgorithmException | KeyManagementException e) {
            e.printStackTrace();
            return null;
        }
    }
}

3. 在OkHttp的构建过程中，使用自定义的SSLContext：

import okhttp3.OkHttpClient;

public class MyHttpClient {
    public static OkHttpClient getHttpClient() {
        OkHttpClient.Builder builder = new OkHttpClient.Builder();

        // 设置自定义的SSLContext
        SSLSocketFactory sslSocketFactory = CustomSSLContext.getSocketFactory();
        if (sslSocketFactory != null) {
            builder.sslSocketFactory(sslSocketFactory, new CustomTrustManager());
        }

        // 其他配置
        // ...

        return builder.build();
    }
}

通过以上步骤，你可以在使用OkHttp3进行网络请求时，处理客户端证书错误的情况。当然，这只是一个基本示例，你还可以根据实际情况进行更多的定制。