你可以从Java/Kotlin Activity中打印哈希键。部分代码已弃用，但这里是包含新旧代码的完整解决方案。

private fun printHashKey(context: Context) {
    try {

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
            val packageInfo: PackageInfo = context.packageManager.getPackageInfo(
                context.packageName,
                PackageManager.GET_SIGNING_CERTIFICATES
            )

            for (signature in packageInfo.signingInfo.apkContentsSigners) {
                val md = MessageDigest.getInstance("SHA")
                md.update(signature.toByteArray())
                Log.d("KeyHash:", Base64.encodeToString(md.digest(), Base64.DEFAULT))
            }
        } else {
            val packageInfo: PackageInfo = context.packageManager.getPackageInfo(
                context.packageName,
                PackageManager.GET_SIGNATURES
            )

            for (signature in packageInfo.signatures) {
                val md = MessageDigest.getInstance("SHA")
                md.update(signature.toByteArray())
                Log.d("KeyHash:", Base64.encodeToString(md.digest(), Base64.DEFAULT))
            }
        }

    } catch (e: PackageManager.NameNotFoundException) {
        Log.d(TAG, "printHashKey: PackageManager.NameNotFoundException -> $e")
    } catch (e: NoSuchAlgorithmException) {
        Log.d(TAG, "printHashKey: NoSuchAlgorithmException -> $e")
    }
}

对于Android应用程序

这段代码用于在Android应用程序中获取Facebook集成的哈希键。我已经测试了所有的设备，一切正常。只更改此代码的包名:

private void facebookHashKey() {

    try {
        PackageInfo info = getPackageManager().getPackageInfo("com.app.helpcove", PackageManager.GET_SIGNATURES);
        for (Signature signature : info.signatures) {
            MessageDigest md = MessageDigest.getInstance("SHA");
            md.update(signature.toByteArray());
            String hashCode  = Base64.encodeToString(md.digest(), Base64.DEFAULT);
            System.out.println("Print the hashKey for Facebook :"+hashCode);
            Log.d("KeyHash:", Base64.encodeToString(md.digest(), Base64.DEFAULT));
        }
    } catch (NameNotFoundException e) {

    } catch (NoSuchAlgorithmException e) {

    }
}

这是Facebook官方页面上给出的内容:

   keytool -exportcert -alias androiddebugkey -keystore ~/.android/debug.keystore | openssl sha1 -binary | openssl base64

让我把这个命令分解成几个片段。

Look for "keytool.exe". You can search that on the C: drive. You can find it in "java jdk" or "java jre". If you have installed multiple versions, choose any. Open a CMD prompt and go to the above directory where you found "keytool.exe". Clip the "exe`" and paste the above command provided on the Facebook page. You will get an error on entering this that OpenSSL is not recognized as in input output command. Solution : Download "Openssl" from OpenSSL (if you have a 64-bit machine you must download openssl-0.9.8e X64). Extract and save it anywhere... I saved it on the C: drive in the OpenSSl folder Replace the openssl in the above command in which you was getting an error of OpenSSL with "C:\OpenSSL\bin\openssl" at both the places after the pipe, "|". If prompted for a password, enter android.

你会得到你的哈希键。要了解进一步的步骤，请再次参考Facebook页面。

facebook开发者网站上的官方文件:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    // Add code to print out the key hash
    try {
        PackageInfo info = getPackageManager().getPackageInfo(
                "com.facebook.samples.hellofacebook", 
                PackageManager.GET_SIGNATURES);
        for (Signature signature : info.signatures) {
            MessageDigest md = MessageDigest.getInstance("SHA");
            md.update(signature.toByteArray());
            Log.d("KeyHash:", Base64.encodeToString(md.digest(), Base64.DEFAULT));
            }
    } catch (NameNotFoundException e) {

    } catch (NoSuchAlgorithmException e) {

    }

你可以从Java/Kotlin Activity中打印哈希键。部分代码已弃用，但这里是包含新旧代码的完整解决方案。

private fun printHashKey(context: Context) {
    try {

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
            val packageInfo: PackageInfo = context.packageManager.getPackageInfo(
                context.packageName,
                PackageManager.GET_SIGNING_CERTIFICATES
            )

            for (signature in packageInfo.signingInfo.apkContentsSigners) {
                val md = MessageDigest.getInstance("SHA")
                md.update(signature.toByteArray())
                Log.d("KeyHash:", Base64.encodeToString(md.digest(), Base64.DEFAULT))
            }
        } else {
            val packageInfo: PackageInfo = context.packageManager.getPackageInfo(
                context.packageName,
                PackageManager.GET_SIGNATURES
            )

            for (signature in packageInfo.signatures) {
                val md = MessageDigest.getInstance("SHA")
                md.update(signature.toByteArray())
                Log.d("KeyHash:", Base64.encodeToString(md.digest(), Base64.DEFAULT))
            }
        }

    } catch (e: PackageManager.NameNotFoundException) {
        Log.d(TAG, "printHashKey: PackageManager.NameNotFoundException -> $e")
    } catch (e: NoSuchAlgorithmException) {
        Log.d(TAG, "printHashKey: NoSuchAlgorithmException -> $e")
    }
}

1)创建一个密钥来签署您的应用程序，并记住别名。 2)安装OpenSSL。 3)将OpenSSL的bin文件夹放在您的路径中。 4)按照FB-Android-SDK页面上“设置单点登录”中提到的步骤，生成您的哈希密钥。确保您输入了正确的别名和密钥库文件名。 5)在facebook上创建一个应用程序，在移动设备选项卡下，输入这个哈希密钥。