源码及安装文件下载方式一：GetAppSignature.zip
说明：应用程序的签名被封装在 packageInfo 中，所以我们要获得应用程序的签名就需要获得 PackageManager 来获得包含有签名信息的 packageInfo，再通过 packageInfo 获得 Signature 数组，循环遍历将签名进行拼接。
代码运行效果：
package cn.sunzn.getappsignature;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.os.Bundle; import android.text.TextUtils; import android.view.Menu; import android.view.View; import android.widget.EditText; import android.widget.TextView; import android.widget.Toast;public class MainActivity extends Activity {private EditText et_pkgname;private TextView tv_signature;private PackageManager manager;private PackageInfo packageInfo;private Signature[] signatures;private StringBuilder builder;private String signature;public void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);et_pkgname = (EditText) findViewById(R.id.et_pkgname);tv_signature = (TextView) findViewById(R.id.tv_signature);manager = getPackageManager();builder = new StringBuilder();}public void getSignature(View view) {String pkgname = et_pkgname.getText().toString();boolean isEmpty = TextUtils.isEmpty(pkgname);if (isEmpty) {Toast.makeText(this, "应用程序的包名不能为空！", Toast.LENGTH_SHORT);} else {try {/** 通过包管理器获得指定包名包含签名的包信息 **/packageInfo = manager.getPackageInfo(pkgname, PackageManager.GET_SIGNATURES);/******* 通过返回的包信息获得签名数组 *******/signatures = packageInfo.signatures;/******* 循环遍历签名数组拼接应用签名 *******/for (Signature signature : signatures) {builder.append(signature.toCharsString());}/************** 得到应用签名 **************/signature = builder.toString();tv_signature.setText(signature);} catch (NameNotFoundException e) {e.printStackTrace();}}}public boolean onCreateOptionsMenu(Menu menu) {getMenuInflater().inflate(R.menu.activity_main, menu);return true;} }