获取Android版本信息和程序版本号

public class MainActivity extends ActionBarActivity {
     private TextView mTextView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //获取当前项目版本号
        mTextView = (TextView) findViewById(R.id.textView1);
        try {
            getVersionName();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        //Android系统版本信息
    String    Model_VERSION="Android系统版本信息: " + android.os.Build.MODEL + ",API "
        + android.os.Build.VERSION.SDK + ",Android "
        + android.os.Build.VERSION.RELEASE;
    //显示信息
    try {
            mTextView.setText("当前程序版本: "+ getVersionName()+"\n"+Model_VERSION );
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
      private String getVersionName() throws Exception
       {
               // 获取packagemanager的实例
               PackageManager packageManager = getPackageManager();
               // getPackageName()是你当前类的包名，0代表是获取版本信息
               PackageInfo packInfo = packageManager.getPackageInfo(getPackageName(),0);
               String version = packInfo.versionName;
               return version;
       }}