如何在片段中增加視圖？

Question

活動開始時，我正在嘗試將內容分配給片段中的微調框。 我發現，首先需要對片段進行膨脹，對布局進行膨脹，然后對視圖進行膨脹，以便為其分配以下代碼：

 spinner.setAdapter(adapter);

我在類似的問題上看過其他文章，但沒有任何運氣。 最終，我不是要修復代碼，而是要找到一段代碼來執行spinner.setAdapter（adapter）; 沒有得到NullPointerException。 活動開始時需要執行此操作，因此從根本上講它需要涉及onCreate（）方法。 這樣做：

 Spinner spinner = (Spinner) findViewById(R.id.spinner1);
    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
            R.array.priority_array, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinner.setAdapter(adapter);

將此代碼放入onCreate（）會給我一個NullPointerException，因為微調框位於片段而不是活動內。

這是我正在嘗試的當前代碼，該代碼不起作用，但是再次，我正在尋找問題的解決方案而不是我的代碼：

 public class ActivityInfo extends ActionBarActivity {

Spinner b;
Myfragment fragment;

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

    Intent intent = getIntent();
    String name = intent.getStringExtra("Name");

    FragmentManager fragmentManager = getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    fragment = new Myfragment();
    fragmentTransaction.add(R.id.RelLayout, fragment);
    fragmentTransaction.commit();

    b = (Spinner) findViewById(R.id.spinner1);
    fragment.addSpinner();





}

@Override
public boolean onCreateOptionsMenu(Menu menu) {

    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.activity_info, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

/**
 * A placeholder fragment containing a simple view.
 */

public static class Myfragment extends Fragment {

    RelativeLayout relativeLayout; 
     View rootView;
     @Override
        public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
           relativeLayout = (RelativeLayout) rootView.findViewById(R.id.RelLayout);
        }
     @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                     Bundle savedInstanceState) {
        rootView = inflater.inflate(R.layout.fragment_activity_info, container, false);

         return rootView;
         }
     public void addSpinner()
      {

         Spinner spin = new Spinner(getActivity()); // needs activity context
        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(getActivity(),
                R.array.priority_array, android.R.layout.simple_spinner_item);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spin.setAdapter(adapter);
         relativeLayout.addView(spin);
      }
}

}

Answer 1

嘗試這樣做：

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.fragment_activity_info, null);
    Spinner spinner = (Spinner) rootView.findViewById(R.id.spinner1);

    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(getActivity(),
        R.array.priority_array, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinner.setAdapter(adapter);

    return rl;
}