更改片段中的 ListView 元素

Question

我想在包含卡片的片段中使用 for 循环（如图所示）更改每个 "test test" TextView，以便它显示，例如，它在 ArrayAdapter 中的位置。（因此，Arnaud Dubois 使用“1”而不是 "test test"，John Snow 使用“2”，依此类推）...

我坚持认为这应该在片段中完成，而不是在数组适配器中完成 class。

我似乎无法从片段本身访问 TextView，只能在 ArrayAdapter 中访问 class。我这里有一些片段代码，但元素没有改变。应该更新每个元素的代码在 "onConfirmedFriendsReceivedEvent".

public class FriendsFragment extends BaseFragment implements MaterialSearchBar.OnSearchActionListener {

ListView mFriendsList;
ConfirmedFriendsAdapter adapter;

private MaterialSearchBar searchBar;

View root_view;

public FriendsFragment(){

}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState){
    View view = inflater.inflate(R.layout.fragment_friends, container, false);

    root_view = view;

    initUI(view);
    initEvent(view);

    return view;
}

public static FriendsFragment newInstance(@Nullable Bundle params){
    Bundle args = (params == null) ? new Bundle() : params;
    FriendsFragment fragment = new FriendsFragment();
    fragment.setArguments(args);
    return fragment;
}

@Override
void initUI(@Nullable final View view){
    mFriendsList = view.findViewById(R.id.friends_list);
    mFriendsList.setEmptyView(view.findViewById(R.id.empty));

    searchBar = (MaterialSearchBar) root_view.findViewById(R.id.friends_searchBar);
    searchBar.setHint("Search friends...");
    //enable searchbar callbacks
    searchBar.setOnSearchActionListener(this);

}

@Override
void initEvent(@Nullable final View view){
    FriendsDataManager.getConfirmedFriends();
}

@Override
public void onSearchStateChanged(boolean enabled) {
    String s = enabled ? "enabled" : "disabled";
    Toast.makeText(getContext(), "Search " + s, Toast.LENGTH_SHORT).show();
    //if (!searchBar.isSearchEnabled()) searchBar.enableSearch();
}

@Override
public void onSearchConfirmed(CharSequence text) {
    String search = text.toString();
    FriendsDataManager.getSearchedFriends(search);
}

@Override
public void onButtonClicked(int buttonCode) {
    switch (buttonCode) {
        case MaterialSearchBar.BUTTON_NAVIGATION:
            Toast.makeText(getContext(), "Machin truc", Toast.LENGTH_SHORT).show();
            break;
        case MaterialSearchBar.BUTTON_SPEECH:
            break;
        case MaterialSearchBar.BUTTON_BACK:
            FriendsDataManager.getConfirmedFriends();
            break;
    }
}

@Subscribe
public void onConfirmedFriendsReceived(ConfirmedFriendsEvent event){
    adapter = new ConfirmedFriendsAdapter(getActivity(), event.mConfirmedFriends);
    mFriendsList.setAdapter(adapter);
    adapter.setNotifyOnChange(true);
    for(int i=0; i<adapter.getCount(); i++){
        View v = getViewByPosition(i, mFriendsList);
        TextView msg = v.findViewById(R.id.friend_message);
        msg.setText(i);
    }
}

public View getViewByPosition(int pos, ListView listView) {
    final int firstListItemPosition = listView.getFirstVisiblePosition();
    final int lastListItemPosition = firstListItemPosition + listView.getChildCount() - 1;

    if (pos < firstListItemPosition || pos > lastListItemPosition ) {
        return listView.getAdapter().getView(pos, null, listView);
    } else {
        final int childIndex = pos - firstListItemPosition;
        return listView.getChildAt(childIndex);
    }
}

这里是 ArrayAdapter class 的代码。请注意，"setMail" 和 "getMail" 方法无法从片段访问（到目前为止）。我希望能够从片段中访问它。

public class ConfirmedFriendsAdapter extends ArrayAdapter<ConfirmedFriend> {

private final List<ConfirmedFriend> mConfirmedFriends;
private final Context mContext;

private GeoDataClient geoDataClient;
private Place currentPlace;

String mail;

TextView friend_message;
TextView friend_position;

public ConfirmedFriendsAdapter(@NonNull final Context context, @NonNull final List<ConfirmedFriend> objects){
    super(context, R.layout.fragment_friends, objects);
    mConfirmedFriends = objects;
    mContext = context;
}

@NonNull
@Override
public View getView(final int position, @Nullable View convertView, @NonNull final ViewGroup parent){

    final ConfirmedFriend confirmedFriend = mConfirmedFriends.get(position);
    if(convertView == null){
        convertView = LayoutInflater.from(mContext).inflate(R.layout.item_friends_feed, parent, false);
    }

    mail = confirmedFriend.getDest_user().getMail();

    TextView friend_name = convertView.findViewById(R.id.friend_name);
    TextView friend_asl = convertView.findViewById(R.id.friend_asl);
    friend_message = convertView.findViewById(R.id.friend_message);
    friend_position = convertView.findViewById(R.id.friend_position);


    DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
    Date date = new Date();
    String now = dateFormat.format(date);

    try {
        Date birthdate = new SimpleDateFormat("yyyy-MM-dd").parse(confirmedFriend.getDest_user().getBirthday());
        Date nowDate = new SimpleDateFormat("yyyy-MM-dd").parse(now);
        // validate inputs ...
        DateFormat formatter = new SimpleDateFormat("yyyyMMdd");
        int d1 = Integer.parseInt(formatter.format(birthdate));
        int d2 = Integer.parseInt(formatter.format(nowDate));
        int age = (d2 - d1) / 10000;
        friend_asl.setText(confirmedFriend.getDest_user().getGender() + ", " + age);
    } catch (ParseException e) {
        e.printStackTrace();
    }

    friend_name.setText(confirmedFriend.getDest_user().getFirstName() + " " + confirmedFriend.getDest_user().getLastName());


    return convertView;

}

public String getMail() {
    return mail;
}

public void setMail(String mail) {
    this.mail = mail;
}

Answer 1

如果您想在片段中执行此操作，请更新 ArrayAdapter 的列表元素并在适配器上调用 notifyDataSetChanged()，这将刷新列表。

你的情况：

添加新变量或使用 ConfirmedFriend 中的现有变量。
更新 onConfirmedFriendsReceived() 中的那个变量。
更新 mConfirmedFriends 列表后将其传递给适配器。
在适配器或片段中调用 notifyDatasetChanged()。
在 ArrayAdapter 的 getView() 方法中，将 ConfirmedFriend 的变量设置为 TextView。

更改片段中的 ListView 元素

Change ListView element in fragment

android

listview

adapter

android-fragments