获取versionName和versionCode

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        PackageManager packageManager = getPackageManager();
        // getPackageName()是你当前类的包名
        PackageInfo packInfo = null;
        try {
            packInfo = packageManager.getPackageInfo(getPackageName(), 0);
        } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
        }
        if (packInfo != null) {
            String version = packInfo.versionName;
            int versionCode = packInfo.versionCode;
            Toast.makeText(this, version + "----" + versionCode, Toast.LENGTH_SHORT).show();
        }
    }
}