Android5.0以上APP签名校验

工做须要须要对App进行签名校验，项目基于5.1开发。

流程是提取一个现有app提取签名做为验证码，对未安装的应用获取签名进行对比校验。

提取已安装应用签名

public static String getSingInfo(String pkgName, Context c) {
        try {
            PackageInfo packageInfo = c.getPackageManager().getPackageInfo(pkgName, PackageManager.GET_SIGNATURES);
            Signature[] signs = packageInfo.signatures;
            Signature sign = signs[0];


            return sign.toCharsString();
//          parseSignature(sign.toByteArray());
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

提取未安装应用签名，其中注释掉的是5.0之前的方法

public static String showUninstallAPKSignatures(String apkPath) {
        String PATH_PackageParser = "android.content.pm.PackageParser";
        try {
//        // apk包的文件路径
//        // 这是一个Package 解释器, 是隐藏的
//        // 构造函数的参数只有一个, apk文件的路径
//        // PackageParser packageParser = new PackageParser(apkPath);
//        Class pkgParserCls = Class.forName(PATH_PackageParser);
//        Class[] typeArgs = new Class[1];
//        typeArgs[0] = String.class;
//        Constructor pkgParserCt = pkgParserCls.getConstructor(typeArgs);
//        Object[] valueArgs = new Object[1];
//        valueArgs[0] = apkPath;
//        Object pkgParser = pkgParserCt.newInstance(valueArgs);
//        Log.i(TAG, "pkgParser:" + pkgParser.toString());
//        // 这个是与显示有关的, 里面涉及到一些像素显示等等, 咱们使用默认的状况
//        DisplayMetrics metrics = new DisplayMetrics();
//        metrics.setToDefaults();
//        // PackageParser.Package mPkgInfo = packageParser.parsePackage(new
//        // File(apkPath), apkPath,
//        // metrics, 0);
//        typeArgs = new Class[4];
//        typeArgs[0] = File.class;
//        typeArgs[1] = String.class;
//        typeArgs[2] = DisplayMetrics.class;
//        typeArgs[3] = Integer.TYPE;
//        Method pkgParser_parsePackageMtd = pkgParserCls.getDeclaredMethod(
//                "parsePackage", typeArgs);
//        valueArgs = new Object[4];
//        valueArgs[0] = new File(apkPath);
//        valueArgs[1] = apkPath;
//        valueArgs[2] = metrics;
//        valueArgs[3] = PackageManager.GET_SIGNATURES;

            //以上方法在Android L之前能够用

            Object pkgParser;
            Class pkgParserCls = Class.forName(PATH_PackageParser);
            Constructor<?> pkgParserCt;
            Class<?>[] typeArgs = {String.class};
            Object[] valueArgs = {apkPath};
            Method pkgParser_parsePackageMtd;
            Object pkgParserPkg;
            if (Build.VERSION.SDK_INT >= 21) {
                //noinspection NullArgumentToVariableArgMethod
                Class[] cNull = null;
                Object[] oNull = null;
                pkgParserCt = pkgParserCls.getConstructor(cNull);
                //noinspection NullArgumentToVariableArgMethod
                pkgParser = pkgParserCt.newInstance(oNull);
                typeArgs = new Class[2];
                typeArgs[0] = File.class;
                typeArgs[1] = Integer.TYPE;
                pkgParser_parsePackageMtd = pkgParserCls.getDeclaredMethod("parsePackage", typeArgs);

                valueArgs = new Object[2];
                valueArgs[0] = new File(apkPath);
                valueArgs[1] = 0;

                pkgParserPkg = pkgParser_parsePackageMtd.invoke(pkgParser, valueArgs);
            } else {
                pkgParserCt = pkgParserCls.getConstructor(typeArgs);
                pkgParser = pkgParserCt.newInstance(valueArgs);

                typeArgs = new Class<?>[]{File.class, String.class, DisplayMetrics.class, int.class};
                pkgParser_parsePackageMtd = pkgParserCls.getDeclaredMethod("parsePackage", typeArgs);

                DisplayMetrics metrics = new DisplayMetrics();
                metrics.setToDefaults();

                valueArgs = new Object[4];
                valueArgs[0] = new File(apkPath);
                valueArgs[1] = apkPath;
                valueArgs[2] = metrics;
                valueArgs[3] = 0;

                pkgParserPkg = pkgParser_parsePackageMtd.invoke(pkgParser, valueArgs);
            }
//        Object pkgParserPkg = pkgParser_parsePackageMtd.invoke(pkgParser,
//                valueArgs);

            typeArgs = new Class[2];
            typeArgs[0] = pkgParserPkg.getClass();
            typeArgs[1] = Integer.TYPE;
            Method pkgParser_collectCertificatesMtd = pkgParserCls
                    .getDeclaredMethod("collectCertificates", typeArgs);
            valueArgs = new Object[2];
            valueArgs[0] = pkgParserPkg;
            valueArgs[1] = PackageManager.GET_SIGNATURES;
            pkgParser_collectCertificatesMtd.invoke(pkgParser, valueArgs);
            // 应用程序信息包, 这个公开的, 不过有些函数, 变量没公开
            Field packageInfoFld = pkgParserPkg.getClass().getDeclaredField(
                    "mSignatures");
            Signature[] info = (Signature[]) packageInfoFld.get(pkgParserPkg);

            Log.i(TAG, info[0].toCharsString());
            return info[0].toCharsString();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }