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在工具栏中的活动中，我得到了一个按钮，该按钮需要从片段中调用方法并更新该片段中的列表。现在这是一个错误。调用活动
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()){
case R.id.menu_sort:
ListFragment listFragment = new ListFragment();
listFragment.sortByPopularity();
break;
}
return super.onOptionsItemSelected(item);
}
片段代码。未附加 Activity 时发现错误。但没有上下文
public class ListFragment extends Fragment implements ListAdapter.ItemClickListener {
/**
* Needed
*/
RecyclerView recyclerView;
View view;
List<BasePojo.Result> list;
ListAdapter listAdapter;
public ListFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
/**
* Main Initialization
*/
view = inflater.inflate(R.layout.fragment_list, container, false);
recyclerView = view.findViewById(R.id.recycler_list_detailed);
recyclerView.setLayoutManager(new GridLayoutManager(getActivity(), 2));
list = new ArrayList<>();
listAdapter = new ListAdapter(list, setOnItemClickCallback());
recyclerView.setAdapter(listAdapter);
RetrofitClient.getApiService().getPhotosList(getString(R.string.api_key)).enqueue(new Callback<BasePojo>() {
@Override
public void onResponse(Call<BasePojo> call, Response<BasePojo> response) {
BasePojo basePojo = response.body();
list.addAll(basePojo.getResults());
recyclerView.getAdapter().notifyDataSetChanged();
}
@Override
public void onFailure(Call<BasePojo> call, Throwable t) {
Log.d("tag", "Response failed" + t.toString());
}
});
return view;
}
@Override
public void onItemClick(View view, int position) {
Log.v("in on click", "value " + position);
}
private OnItemClickListener.OnItemClickCallback setOnItemClickCallback() {
OnItemClickListener.OnItemClickCallback onItemClickCallback = new OnItemClickListener.OnItemClickCallback() {
@Override
public void onItemClicked(View view, int position) {
BasePojo.Result itemClicked = list.get(position);
Bundle bundle = new Bundle();
bundle.putString("title", itemClicked.getOriginalTitle());
bundle.putString("overview", itemClicked.getOverview());
bundle.putString("release_date", itemClicked.getReleaseDate());
bundle.putString("vote_average", itemClicked.getVoteAverage().toString());
bundle.putString("poster_path", itemClicked.getPosterPath());
DetailedFragment detailedFragment = new DetailedFragment();
detailedFragment.setArguments(bundle);
FragmentManager manager = getActivity().getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(R.id.main_frame_list, detailedFragment);
Log.d("tag", "title is 111 " + bundle.get("title"));
transaction.commit();
}
};
return onItemClickCallback;
}
@Override
public void onAttachFragment(Fragment childFragment) {
super.onAttachFragment(childFragment);
}
public void sortByPopularity() {
RetrofitClient.getApiService().getPopularList(getString(R.string.api_key)).enqueue(new Callback<BasePojo>() {
@Override
public void onResponse(Call<BasePojo> call, Response<BasePojo> response) {
BasePojo basePojo = response.body();
list.addAll(basePojo.getResults());
recyclerView.getAdapter().notifyDataSetChanged();
}
@Override
public void onFailure(Call<BasePojo> call, Throwable t) {
Log.d("tag", "Response failed" + t.toString());
}
}); }
}
这是一个错误
05-09 12:48:26.915 5775-5775/com.borisruzanov.popularmovies E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.borisruzanov.popularmovies, PID: 5775
java.lang.IllegalStateException: Fragment ListFragment{6dbd6de} not attached to a context.
at android.support.v4.app.Fragment.requireContext(Fragment.java:614)
at android.support.v4.app.Fragment.getResources(Fragment.java:678)
at android.support.v4.app.Fragment.getString(Fragment.java:700)
at com.borisruzanov.popularmovies.ListFragment.sortByPopularity(ListFragment.java:110)
at com.borisruzanov.popularmovies.MainActivity.onOptionsItemSelected(MainActivity.java:47)
at android.app.Activity.onMenuItemSelected(Activity.java:3204)
at android.support.v4.app.FragmentActivity.onMenuItemSelected(FragmentActivity.java:407)
at android.support.v7.app.AppCompatActivity.onMenuItemSelected(AppCompatActivity.java:195)
at android.support.v7.view.WindowCallbackWrapper.onMenuItemSelected(WindowCallbackWrapper.java:108)
at android.support.v7.view.WindowCallbackWrapper.onMenuItemSelected(WindowCallbackWrapper.java:108)
at android.support.v7.app.ToolbarActionBar$2.onMenuItemClick(ToolbarActionBar.java:63)
at android.support.v7.widget.Toolbar$1.onMenuItemClick(Toolbar.java:203)
at android.support.v7.widget.ActionMenuView$MenuBuilderCallback.onMenuItemSelected(ActionMenuView.java:780)
at android.support.v7.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:822)
at android.support.v7.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:171)
at android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:973)
at android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:963)
at android.support.v7.widget.ActionMenuView.invokeItem(ActionMenuView.java:624)
at android.support.v7.view.menu.ActionMenuItemView.onClick(ActionMenuItemView.java:150)
at android.view.View.performClick(View.java:5610)
at android.view.View$PerformClick.run(View.java:22265)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
非常感谢您的时间和帮助。如果我的问题看起来不太好，请做笔记，我会教如何更好地提问
原文由 Bo Z 发布，翻译遵循 CC BY-SA 4.0 许可协议
android
创建一个片段实例是不够的。
它需要通过事务附加到Activity：
提交成功后，调用片段中的
onAttach方法，创建视图，然后您可以与其视图交互。在您的情况下，创建片段实例并将其附加到活动中
onCreate，然后在点击事件中调用sortByPopularity。阅读有关片段生命周期的更多信息： https ://developer.android.com/guide/components/fragments