Get the version name and version code from AndroidMenifest.xml

通常我們都會在AndroidManifest.xml中，添加程式版本名稱和版本資訊，如下圖

In the MainActivity.java

 
protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 //toast version
 try {
  int versionCode = this.getPackageManager().getPackageInfo(this.getPackageName(), 0).versionCode;
  String versionName = this.getPackageManager().getPackageInfo(this.getPackageName(), 0).versionName;
  String toastString = versionCode + "/" + versionName;
  Toast.makeText(this, toastString, Toast.LENGTH_SHORT).show();
 } catch (NameNotFoundException e) {
  Toast.makeText(this, "NameNotFoundException", Toast.LENGTH_SHORT).show();
 }
 //
}