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")
    }
}

目前Facebook Android教程中的说明在Windows下并不适用。他们的例子展示了如何将keytool输出输出到openssl，但是如果你在Windows下尝试这样做，由于某些原因输出是无效的。我发现我必须使用中间文件才能让它正常工作。以下是对我有用的步骤:

首先从谷歌下载openssl for Windows。

C:\Users\Me>keytool -exportcert -alias my_key -keystore my.keystore -storepass PASSWORD > mycert.bin

C:\Users\Me>openssl sha1 -binary mycert.bin > sha1.bin

C:\Users\Me>openssl base64 -in sha1.bin -out base64.txt

运行这些命令后，有效的散列存储在文件base64.txt中。复制粘贴到你的Facebook应用设置中。

这是Xamarin的版本

private void printKeyHash()
{
    try
    {
        PackageInfo info = PackageManager.GetPackageInfo(PackageName, PackageInfoFlags.Signatures);
        foreach (var signature in info.Signatures)
        {
            MessageDigest md = MessageDigest.GetInstance("SHA1");
            md.Update(signature.ToByteArray());
            var hash = Base64.EncodeToString(md.Digest(), Base64Flags.Default);
            Log.Debug("KeyHash:", hash);
        }
    }
    catch (PackageManager.NameNotFoundException e)
    {

    }
    catch (NoSuchAlgorithmException e)
    {

    }
}

在一个类似的问题上，我发现这对我很有效:

将你想知道散列值的apkname.apk文件复制到“Java\jdk1.7.0_79\bin”文件夹中 执行keytool -list -printcert -jarfile apkname.apk 复制SHA1值并使用此站点进行转换 使用转换后的Keyhash值(例如:zaHqo1xcaPv6CmvlWnJk3SaNRIQ=)

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")
    }
}

Kotlin代码获取哈希键

 private fun logHashKey() {
    try {
        val info = getPackageManager().getPackageInfo("your.package.name", PackageManager.GET_SIGNING_CERTIFICATES);
        for (signature in info.signingInfo.signingCertificateHistory) {

            val md = MessageDigest.getInstance("SHA");
            md.update(signature.toByteArray());
            val something = Base64.getEncoder().encodeToString(md.digest());
            Log.e("hash key", something);
        }
    } catch (e1: PackageManager.NameNotFoundException) {
        Log.e("name not found", e1.toString());
    } catch (e: NoSuchAlgorithmException) {
        Log.e("no such an algorithm", e.toString());
    } catch (e: Exception) {
        Log.e("exception", e.toString());
    }
}

请不要忘记在调试和发布环境中生成键，因为它们会随着构建设置而变化。