Question

当我按下Bundle中列出的某个项目时，我试图通过setArguments()使用Fragment从活动传递值到另一个类ListView。

如下所示，我使用Log.i语句来了解收到的Bundle是否为null。不幸的是，它总是null，因此，在TextView扩展Fragment的类的指定FragmentClass上没有数据显示。我错过了什么或代码有什么问题。

@Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // TODO Auto-generated method stub View view = inflater.inflate(R.layout.fragmentclasslayout, null); return view; } @Override public void onActivityCreated(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onActivityCreated(savedInstanceState); if (getArguments() != null) { Log.i(TAG, "getArgument is not null"); int value = getArguments().getInt("pos"); TextView tv = (TextView) getView().findViewById(R.id.tvID); tv.setTextSize(value); tv.setText("size = "+value*10); }else { Log.i(TAG, "getArgument is null"); } }

MainClass_implements_onItemSelectedListener

setContentView(R.layout.mainactivity); ListView mListView = (ListView) findViewById(R.id.list); ArrayAdapter<String> mArrayAdapter = new ArrayAdapter<String>(getApplicationContext(), R.layout.listviewlayout, R.id.tv, string); mListView.setAdapter(mArrayAdapter); mListView.setOnItemSelectedListener(this); } @Override public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { // TODO Auto-generated method stub Fragment f = new FragmentClass(); Bundle bundle = new Bundle(); bundle.putInt("pos", (position+1)); FragmentClass fc = new FragmentClass().newInstance(bundle); //f.setArguments(bundle); FragmentTransaction t = getFragmentManager().beginTransaction(); t.replace(R.id.fragment00ID, f); t.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN); t.addToBackStack(null); t.commit(); }

mainActivity_layout

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/container" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="horizontal" tools:ignore="MergeRootFrame"> <ListView android:id="@+id/list" android:layout_width="100px" android:layout_weight="1" android:layout_height="match_parent" /> <fragment android:name="com.example.fragmentwithlistview.FragmentClass" android:id="@+id/fragment00ID" android:layout_toRightOf="@+id/list" android:layout_width="wrap_content" android:layout_height="fill_parent" android:layout_weight="4" />

FragmentClass_layout

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/container" android:layout_width="fill_parent" android:layout_height="fill_parent" tools:ignore="MergeRootFrame" android:background="#FFFFFF"> <TextView android:id="@+id/tvID" android:textColor="#000000" android:layout_width="fill_parent" android:layout_height="fill_parent"/>

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Answer 1

最好使用静态方法进行实例化：

public class FragmentClass extends Fragment {

  public static FragmentClass newInstance(Bundle b) {
    FragmentClass fragment = new FragmentClass();
    fragment.setArguments(b);

    return fragment;
  }

  public View onCreateView(LayoutInflater inflater, ViewGroup container,
          Bundle savedInstanceState) {
      View view = inflater.inflate(R.layout.fragmentclasslayout, null);

      if (getArguments() != null) {
          Log.i(TAG, "getArgument is not null");
          int value = getArguments().getInt("pos");           
          TextView tv = (TextView) view.findViewById(R.id.tvID);
          tv.setTextSize(value);
          tv.setText("size = "+value*10);
      } else {
          Log.i(TAG, "getArgument is null");
      }

      return view;
  }
}

然后简单地调用该方法并将arguments-bundle作为参数传递：

Bundle bundle = new Bundle();
bundle.putInt("pos", (position+1));
FragmentClass f = FragmentClass.newInstance(bundle);

此外，请勿使用onActivityCreated获取FragmentClass中的参数，使用onCreateView或必要onStart或onResume。看看片段生命周期：http://developer.android.com/guide/components/fragments.html#Lifecycle

Answer 2

您可以在传递活动时使用

Bundle bundle = new Bundle();
    bundle.putString("model", strDeckNumber);

                    final FragmentTransaction t = getActivity().getSupportFragmentManager().beginTransaction();
                    Frag1 newFragment = new Frag1();
                    newFragment.setArguments(bundle);
                    t.replace(R.id.fragment_container, newFragment);
                    t.addToBackStack(TAG);
                    t.commit();

接收片段

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

            strSeriesNumber = getArguments().getString("model");
}

getArgument是NULL，为什么？

2 个答案: