import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import android.os.Bundle;
import android.app.Activity;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.pm.Signature;
import android.text.Editable;
import android.util.Base64;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends Activity {

    Button btn;
    EditText et;
    PackageInfo info;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btn=(Button)findViewById(R.id.button1);
        et=(EditText)findViewById(R.id.editText1);
        btn.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

                try {
                    info = getPackageManager().getPackageInfo("com.example.id", PackageManager.GET_SIGNATURES);
                    for (Signature signature : info.signatures) {
                        MessageDigest md;
                        md = MessageDigest.getInstance("SHA");
                        md.update(signature.toByteArray());
                        String something = new String(Base64.encode(md.digest(), 0));
                        //String something = new String(Base64.encodeBytes(md.digest()));
                        et.setText("" + something);
                        Log.e("hash key", something);
                    }
                } catch (NameNotFoundException e1) {
                    Log.e("name not found", e1.toString());
                } catch (NoSuchAlgorithmException e) {
                    Log.e("no such an algorithm", e.toString());
                } catch (Exception e) {
                    Log.e("exception", e.toString());
                }
            }
        });
    }



}

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。

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。

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import android.os.Bundle;
import android.app.Activity;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.pm.Signature;
import android.text.Editable;
import android.util.Base64;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends Activity {

    Button btn;
    EditText et;
    PackageInfo info;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btn=(Button)findViewById(R.id.button1);
        et=(EditText)findViewById(R.id.editText1);
        btn.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

                try {
                    info = getPackageManager().getPackageInfo("com.example.id", PackageManager.GET_SIGNATURES);
                    for (Signature signature : info.signatures) {
                        MessageDigest md;
                        md = MessageDigest.getInstance("SHA");
                        md.update(signature.toByteArray());
                        String something = new String(Base64.encode(md.digest(), 0));
                        //String something = new String(Base64.encodeBytes(md.digest()));
                        et.setText("" + something);
                        Log.e("hash key", something);
                    }
                } catch (NameNotFoundException e1) {
                    Log.e("name not found", e1.toString());
                } catch (NoSuchAlgorithmException e) {
                    Log.e("no such an algorithm", e.toString());
                } catch (Exception e) {
                    Log.e("exception", e.toString());
                }
            }
        });
    }



}

最简单的解决方案:

不加哈希键，实现其他所有东西 当facebook登录被按下，你会得到一个错误说“无效的键哈希。密钥哈希“xxx”不匹配任何存储密钥. ...” 打开facebook应用程序仪表板，并添加哈希值“xxx=”(“xxx”哈希值来自错误+“=”符号)

下载openSSL for windows，你可以在这里找到64位和32位的 解压缩下载的文件 在C盘中创建文件夹名为openSSL 将所有提取的项目复制到openSSL文件夹(bin,include,lib, openSSL .cnf) 获取android调试密钥库，默认位置为

C:\Users\username\.android\ debug.keystore

现在获得命令提示符并粘贴这段代码

keytool -exportcert -alias androiddebugkey -keystore C：\Users\username.android\debug.keystore |“C：\openSSL\bin\openssl” sha1 -binary |“C：\openSSL\bin\openssl” base64

按enter键，你会得到28位的键码