闲着没事儿写了个小 demo ，获取手机上已安装应用信息，系统应用和 非系统应用

MD5 SHA1 SHA256 签名信息 点击签名信息可复制到剪切板，

GitHub：https://github.com/sunan-n/GetAppInfo

如下图：

<span style="white-space:pre;"> </span>主要就是这个方法，传参数进来获取相应的签名类型 信息<br />
&nbsp; &nbsp; public static String getSignaturesInfo(Context context, String packageName, String tpye) {<br />
//&nbsp; &nbsp; &nbsp; &nbsp; //获取包管理器<br />
&nbsp; &nbsp; &nbsp; &nbsp; PackageManager pm = context.getPackageManager();<br />
&nbsp; &nbsp; &nbsp; &nbsp; //返回包括在包中的签名信息<br />
&nbsp; &nbsp; &nbsp; &nbsp; int flags = PackageManager.GET_SIGNATURES;<br />
&nbsp; &nbsp; &nbsp; &nbsp; PackageInfo packageInfo = null;<br />
&nbsp; &nbsp; &nbsp; &nbsp; try {<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //获得包的所有内容信息类<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; packageInfo = pm.getPackageInfo(packageName, flags);<br />
&nbsp; &nbsp; &nbsp; &nbsp; } catch (PackageManager.NameNotFoundException e) {<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; e.printStackTrace();<br />
&nbsp; &nbsp; &nbsp; &nbsp; }<br />
&nbsp; &nbsp; &nbsp; &nbsp; //签名信息<br />
&nbsp; &nbsp; &nbsp; &nbsp; Signature[] signatures = packageInfo.signatures;<br />
&nbsp; &nbsp; &nbsp; &nbsp; byte[] cert = signatures[0].toByteArray();<br />
&nbsp; &nbsp; &nbsp; &nbsp; //将签名转换为字节数组流<br />
&nbsp; &nbsp; &nbsp; &nbsp; InputStream input = new ByteArrayInputStream(cert);<br />
&nbsp; &nbsp; &nbsp; &nbsp; //证书工厂类，这个类实现了出厂合格证算法的功能<br />
&nbsp; &nbsp; &nbsp; &nbsp; CertificateFactory cf = null;<br />
&nbsp; &nbsp; &nbsp; &nbsp; try {<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; cf = CertificateFactory.getInstance("X509");<br />
&nbsp; &nbsp; &nbsp; &nbsp; } catch (CertificateException e) {<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; e.printStackTrace();<br />
&nbsp; &nbsp; &nbsp; &nbsp; }<br />
&nbsp; &nbsp; &nbsp; &nbsp; //X509证书，X.509是一种非常通用的证书格式<br />
&nbsp; &nbsp; &nbsp; &nbsp; X509Certificate c = null;<br />
&nbsp; &nbsp; &nbsp; &nbsp; try {<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; c = (X509Certificate) cf.generateCertificate(input);<br />
&nbsp; &nbsp; &nbsp; &nbsp; } catch (CertificateException e) {<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; e.printStackTrace();<br />
&nbsp; &nbsp; &nbsp; &nbsp; }<br />
&nbsp; &nbsp; &nbsp; &nbsp; String hexString = null;<br />
&nbsp; &nbsp; &nbsp; &nbsp; try {<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //加密算法的类，这里的参数可以使MD4,MD5等加密算法<br />
//&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; MessageDigest md = MessageDigest.getInstance("SHA1");<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; MessageDigest md = MessageDigest.getInstance(tpye);<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //获得公钥<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; byte[] publicKey = md.digest(c.getEncoded());<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //字节到十六进制的格式转换<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; hexString = byte2HexFormatted(publicKey);<br />
&nbsp; &nbsp; &nbsp; &nbsp; } catch (NoSuchAlgorithmException e1) {<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; e1.printStackTrace();<br />
&nbsp; &nbsp; &nbsp; &nbsp; } catch (CertificateEncodingException e) {<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; e.printStackTrace();<br />
&nbsp; &nbsp; &nbsp; &nbsp; }<br />
&nbsp; &nbsp; &nbsp; &nbsp; return hexString;<br />
&nbsp; &nbsp; }<br />
<br />