Android获取应用签名方法

    /**
     * 获取应用签名
     *
     * @param context
     * @param packageName
     * @return
     */
    public static String getRawSignatureStr(Context context, String packageName) {
        try {
            Signature[] signs = getRawSignature(context, packageName);
            String signValidString = getSignValidString(signs[0].toByteArray());
            return signValidString;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    public static Signature[] getRawSignature(Context context, String packageName) {
        if (packageName == null || packageName.length() == 0) {
            return null;
        }
        try {
            PackageInfo info = context.getPackageManager().getPackageInfo(packageName, PackageManager.GET_SIGNATURES);
            if (info != null) {
                return info.signatures;
            }
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }

        return null;
    }

    private static String getSignValidString(byte[] paramArrayOfByte) throws NoSuchAlgorithmException {
        MessageDigest localMessageDigest = MessageDigest.getInstance("MD5");
        localMessageDigest.update(paramArrayOfByte);
        return toHexString(localMessageDigest.digest());
    }

    private static String toHexString(byte[] paramArrayOfByte) {
        if (paramArrayOfByte == null) {
            return null;
        }
        StringBuilder localStringBuilder = new StringBuilder(2 * paramArrayOfByte.length);
        for (int i = 0; ; i++) {
            if (i >= paramArrayOfByte.length) {
                return localStringBuilder.toString();
            }
            String str = Integer.toString(0xFF & paramArrayOfByte[i], 16);
            if (str.length() == 1) {
                str = "0" + str;
            }
            localStringBuilder.append(str);
        }
    }