如果所有代码都在 MainActivity 中但不是两个 类，则代码有效

Question

我有两个 classes MainActivity 和 WordBase 。该代码不起作用，但是当我将它从 WordBase class 复制到 MainActivity 时，它起作用了。 这是两个 classes

public class WordsBase {
private Activity context=null;
private View myView;

//  Type of words that user wants to search
private final String Noun="Nomen",Adjectives="Adjectives",Verbs="Verben";


 public WordsBase(Activity context)
     {
        this.context= context;
    }

     // creat the list menu that lets User to choose what type of words wants to search
    public void create () {

       LayoutInflater inflater = context.getLayoutInflater();
        myView = inflater.inflate(R.layout.words_base, null);
       Spinner sp1 = (Spinner) myView.findViewById(R.id.spinner1);

       List<String> arr = new ArrayList<String>();
       arr.add(Noun);
       arr.add(Adjectives);
       arr.add(Verbs);

       ArrayAdapter<String> menu_Adapter = new ArrayAdapter<String>(context,android.R.layout.simple_list_item_1,arr);
       sp1.setAdapter(menu_Adapter);

   }

}

这是 MainActivity

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.words_base);
    WordsBase menu =new WordsBase(this);
    menu.create();

   }
}

Answer 1

您忘记将视图添加到主视图 activity。

你可以return这样的视图

public 查看创建 (){

... return 我的视图； }

在主 activity 中你得到外部相对布局 layout.addview(menu.create());