如果Android模拟器无法信任Charles代理证书，可以尝试以下解决方法：

1. 在Android模拟器中安装Charles代理证书

// 获取Charles代理证书的InputStream
InputStream certificateInputStream = context.getAssets().open("charles-proxy-certificate.pem");

// 保存证书到指定路径
File certificateFile = new File(Environment.getExternalStorageDirectory(), "charles-proxy-certificate.cer");
OutputStream certificateOutputStream = new FileOutputStream(certificateFile);
byte buffer[] = new byte[1024];
int length;
while ((length = certificateInputStream.read(buffer)) != -1) {
    certificateOutputStream.write(buffer, 0, length);
}
certificateOutputStream.flush();
certificateOutputStream.close();
certificateInputStream.close();

// 安装证书
Intent intent = new Intent(Settings.ACTION_SECURITY_SETTINGS);
intent.setData(Uri.fromParts("package", "com.android.settings", null));
startActivity(intent);

2. 在Android模拟器中信任Charles代理证书

// 获取Charles代理证书的InputStream
InputStream certificateInputStream = context.getAssets().open("charles-proxy-certificate.pem");

// 创建KeyStore，并加载Charles代理证书
KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
keyStore.load(null, null);
CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
Certificate certificate = certificateFactory.generateCertificate(certificateInputStream);
keyStore.setCertificateEntry("charles-proxy-certificate", certificate);

// 创建TrustManager，并使用KeyStore初始化
TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
trustManagerFactory.init(keyStore);
TrustManager[] trustManagers = trustManagerFactory.getTrustManagers();

// 创建SSLContext，并使用TrustManager初始化
SSLContext sslContext = SSLContext.getInstance("TLS");
sslContext.init(null, trustManagers, null);

// 设置模拟器使用自定义的SSLContext
HttpsURLConnection.setDefaultSSLSocketFactory(sslContext.getSocketFactory());

这些代码示例分别展示了两种解决方法，第一种是通过安装证书到Android模拟器的系统设置中，第二种是在代码中信任Charles代理证书。您可以根据具体情况选择适合的解决方法。