我有一个标签片段，由下面的课程概述。
有两个选项卡，其中包含信息列表，朋友和群组。我遇到的问题是，“群组”列表首先在“好友”标签中呈现，然后消失，允许“好友”列表在“好友”标签中呈现。但是，在滑动到“组”选项卡时，组列表永远不会呈现。
如何解决这个问题？
选项卡式活动：
public class InvitingFriendsGroupsToEvents extends AppCompatActivity {
/**
* The {@link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {@link FragmentPagerAdapter} derivative, which will keep every
* loaded fragment in memory. If this becomes too memory intensive, it
* may be best to switch to a
* {@link android.support.v4.app.FragmentStatePagerAdapter}.
*/
private SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {@link ViewPager} that will host the section contents.
*/
private ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_inviting_friends_groups_to_events);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_inviting_friends_groups_to_events, 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();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
public PlaceholderFragment() {
}
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_inviting_friends_groups_to_events, container, false);
TextView textView = (TextView) rootView.findViewById(R.id.section_label);
textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));
return rootView;
}
}
/**
* A {@link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public int getCount() {
return 2;
}
@Override
public Fragment getItem(int position) {
// Need to build
// Order/first appearing will be specific to time of day, ie. if in morning, then breakfast/brunch, if midday then lunch, late then dinner
switch (position) {
case 0:
return new InviteFriendsToEventsFragment();
case 1:
return new InviteGroupsToEventsFragment();
}
return null;
}
@Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "Friends";
case 1:
return "Groups";
}
return null;
}
}
}
朋友标签：
public class InviteFriendsToEventsFragment extends Fragment {
// ie. once a fiend is invited, it will show their group on the second tab, the name, who invite them
MyCustomAdapter dataAdapter = null;
SaveSharedPreference preference = new SaveSharedPreference();
final Firebase myFeastFirebase = new Firebase(Constants.getFirebaseUrl());
Firebase presentEventMembers;
Firebase myFriends;
Firebase sentFriendEventInvites; // this will be the grayed out standing invitation
Firebase eventMemberInviteNeedSync;
ValueEventListener getFriendsListener;
ValueEventListener getEventMembersListener;
ValueEventListener getAlreadyInvitedFriendsListener;
String eventID;
String eventName;
ArrayList<Member> mEventMembers = new ArrayList<>();
ArrayList<Member> mFriends = new ArrayList<>();
ArrayList<Member> mAlreadyInvited = new ArrayList<>();
ArrayList<FriendInvite> mFriendsFinalInviteStatuses = new ArrayList<>();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
View view = inflater.inflate(R.layout.invite_friends_to_events, container, false);
Bundle extras = getActivity().getIntent().getExtras();
eventID = extras.getString("eventID");
eventName = extras.getString("eventName");
Log.v("InvitingFriendsToEvents", "Event ID: " + eventID);
Log.v("InvitingFriendsToEvents", "Event Name" + eventName);
//Generate list View from ArrayList
// Get present group members
presentEventMembers = myFeastFirebase.child("eventMembers").child(eventID);
myFriends = myFeastFirebase.child("friends").child(preference.getUserSyncID(getContext()));
sentFriendEventInvites = myFeastFirebase.child("userEventMemberInviteSent").child(preference.getUserSyncID(getContext())).child(eventID);
eventMemberInviteNeedSync = myFeastFirebase.child("eventMemberInviteNeedSync");
getAlreadyInvitedFriendsListener = new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot inviteSnapshot : dataSnapshot.getChildren()) {
Member invitedFriend = new Member();
invitedFriend.setUserUID(inviteSnapshot.getKey());
invitedFriend.setUserName(inviteSnapshot.getValue().toString());
mAlreadyInvited.add(invitedFriend);
Log.v("InvitingFriendsToEvents", "Invite Sent userName is: " + inviteSnapshot.getValue().toString());
Log.v("InvitingFriendsToEvents", "Invite Sent ID is: " + inviteSnapshot.getKey().toString());
}
// Here will be the operation to get the proper setting for
// First: remove from friends, those already in the group:
mFriends.removeAll(mEventMembers);
// Then add to the invite group
for (Member friend : mFriends) {
FriendInvite groupMemberInvite = new FriendInvite();
groupMemberInvite.setUserName(friend.getUserName());
groupMemberInvite.setUserUID(friend.getUserUID());
if (mAlreadyInvited.contains(friend)) {
groupMemberInvite.setInvitedAlready(true);
}
mFriendsFinalInviteStatuses.add(groupMemberInvite);
Log.v("InvitingFriendsToEvents", "Final List UserName is: " + groupMemberInvite.getUserName());
Log.v("InvitingFriendsToEvents", "Final List UserID is: " + groupMemberInvite.getUserUID());
Log.v("InvitingFriendsToEvents", "Final List InviteStatus is: " + groupMemberInvite.isInvitedAlready());
}
//dataAdapter.notifyDataSetChanged();
//create an ArrayAdaptar from the String Array
dataAdapter = new MyCustomAdapter(getActivity(),
R.layout.country_info, mFriendsFinalInviteStatuses);
ListView listView = (ListView) getActivity().findViewById(R.id.listView1);
// Assign adapter to ListView
listView.setAdapter(dataAdapter);
dataAdapter.notifyDataSetChanged();
}
@Override
public void onCancelled(FirebaseError firebaseError) {
}
};
getFriendsListener = new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot friendSnapshot : dataSnapshot.getChildren()) {
if (!friendSnapshot.getKey().equals(preference.getUserSyncID(getContext()))) {
Member friend = new Member();
friend.setUserUID(friendSnapshot.getKey());
friend.setUserName(friendSnapshot.child("userName").getValue().toString());
mFriends.add(friend);
Log.v("InvitingFriendsToEvents", "Friend userName is: " + friendSnapshot.child("userName").getValue().toString());
Log.v("InvitingFriendsToEvents", "Friend user ID is: " + friendSnapshot.getKey().toString());
}
}
// after getting friends
sentFriendEventInvites.addListenerForSingleValueEvent(getAlreadyInvitedFriendsListener);
}
@Override
public void onCancelled(FirebaseError firebaseError) {
Log.v("InvitingFriendsToEvents", "Firebase Error: " + firebaseError.toString());
}
};
getEventMembersListener = new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot groupMemberSnapshot : dataSnapshot.getChildren()) {
if (!groupMemberSnapshot.getKey().equals(preference.getUserSyncID(getContext()))) {
Member groupMember = new Member();
groupMember.setUserUID(groupMemberSnapshot.getKey());
groupMember.setUserName(groupMemberSnapshot.getValue().toString());
mEventMembers.add(groupMember);
Log.v("InvitingFriendsToEvents", "Group member userName is: " + groupMemberSnapshot.getValue().toString());
Log.v("InvitingFriendsToEvents", "Group member user ID is: " + groupMemberSnapshot.getKey().toString());
}
}
// upon completion of getting groups
myFriends.addListenerForSingleValueEvent(getFriendsListener);
}
@Override
public void onCancelled(FirebaseError firebaseError) {
Log.v("InvitingFriendsToEvents", "Firebase Error: " + firebaseError.toString());
}
};
presentEventMembers.addListenerForSingleValueEvent(getEventMembersListener);
//confirmFriendInvites();
return view;
}
private class MyCustomAdapter extends ArrayAdapter<FriendInvite> {
private ArrayList<FriendInvite> groupMemberInviteList;
public MyCustomAdapter(Context context, int textViewResourceId,
ArrayList<FriendInvite> groupMemberInviteList) {
super(context, textViewResourceId, groupMemberInviteList);
this.groupMemberInviteList = new ArrayList<>();
this.groupMemberInviteList.addAll(groupMemberInviteList);
}
private class ViewHolder {
TextView inviteSent;
CheckBox checkBox;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
Log.v("ConvertView", String.valueOf(position));
if (convertView == null) {
LayoutInflater vi = (LayoutInflater) getActivity().getSystemService(
Context.LAYOUT_INFLATER_SERVICE);
convertView = vi.inflate(R.layout.country_info, null);
holder = new ViewHolder();
holder.checkBox = (CheckBox) convertView.findViewById(R.id.checkBox1); // here it is
holder.inviteSent = (TextView) convertView.findViewById(R.id.invite_already_sent);
convertView.setTag(holder);
holder.checkBox.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
CheckBox cb = (CheckBox) v;
FriendInvite groupMemberInivited = (FriendInvite) cb.getTag();
Toast.makeText(getActivity(),
"Clicked on Checkbox: " + cb.getText() +
" is " + cb.isChecked(),
Toast.LENGTH_LONG).show();
groupMemberInivited.setSelected(cb.isChecked());
}
});
} else {
holder = (ViewHolder) convertView.getTag();
}
FriendInvite groupMemberInvite = groupMemberInviteList.get(position);
holder.checkBox.setText(groupMemberInvite.getUserName());
holder.checkBox.setChecked(groupMemberInvite.isSelected());
holder.checkBox.setTag(groupMemberInvite);
// Check if already invited, if so, should remove
if (groupMemberInvite.isInvitedAlready() == true) {
holder.checkBox.setTextColor(Color.GRAY);
holder.checkBox.setClickable(false);
holder.inviteSent.setText("Invite Already Sent");
} else {
holder.inviteSent.setText("");
}
return convertView;
}
}
}
组标签：
public class InviteGroupsToEventsFragment extends Fragment { //即。一旦邀请了一个恶魔，它将在第二个标签上显示他们的小组，名字，谁邀请他们
GroupInviteCustomAdapter dataAdapter = null;
SaveSharedPreference preference = new SaveSharedPreference();
final Firebase myFeastFirebase = new Firebase(Constants.getFirebaseUrl());
Firebase presentEventMembers;
Firebase sentFriendEventInvites; // this will be the grayed out standing invitation
Firebase mGroups;
Firebase mGroupMembers;
Firebase eventMemberInviteNeedSync;
ValueEventListener getFriendsListener;
ValueEventListener getEventMembersListener;
ValueEventListener getAlreadyInvitedFriendsListener;
ValueEventListener getUsersGroups;
String eventID;
String eventName;
ArrayList<Member> mEventMembers = new ArrayList<>();
ArrayList<Member> mFriends = new ArrayList<>();
ArrayList<Member> mAlreadyInvited = new ArrayList<>();
ArrayList<FriendInvite> mFriendsFinalInviteStatuses = new ArrayList<>();
ArrayList<GroupInvite> mUsersGroups = new ArrayList<>();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
View view = inflater.inflate(R.layout.invite_groups_to_events, container, false);
Bundle extras = getActivity().getIntent().getExtras();
eventID = extras.getString("eventID");
eventName = extras.getString("eventName");
Log.v("InvitingFriendsToEvents", "Event ID: " + eventID);
Log.v("InvitingFriendsToEvents", "Event Name" + eventName);
//Generate list View from ArrayList
// Get present group members
presentEventMembers = myFeastFirebase.child("eventMembers").child(eventID);
mGroupMembers = myFeastFirebase.child("groupMembers"); // will append: .child("")
mGroups = myFeastFirebase.child("usersGroups").child(preference.getUserSyncID(getContext()));
sentFriendEventInvites = myFeastFirebase.child("userEventMemberInviteSent").child(preference.getUserSyncID(getContext())).child(eventID);
eventMemberInviteNeedSync = myFeastFirebase.child("eventMemberInviteNeedSync");
getUsersGroups = new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot inviteSnapshot : dataSnapshot.getChildren()) {
GroupInvite invitedGroup = new GroupInvite();
invitedGroup.setGroupSyncID(inviteSnapshot.getKey());
invitedGroup.setGroupName(inviteSnapshot.getValue().toString());
mUsersGroups.add(invitedGroup);
Log.v("InvitingFriendsToEvents", "Invite Sent userName is: " + inviteSnapshot.getValue().toString());
Log.v("InvitingFriendsToEvents", "Invite Sent ID is: " + inviteSnapshot.getKey().toString());
}
dataAdapter = new GroupInviteCustomAdapter(getActivity(),
R.layout.event_invites_groups, mUsersGroups);
ListView listView = (ListView) getActivity().findViewById(R.id.listView1);
// Assign adapter to ListView
listView.setAdapter(dataAdapter);
dataAdapter.notifyDataSetChanged();
}
@Override
public void onCancelled(FirebaseError firebaseError) {
}
};
mGroups.addListenerForSingleValueEvent(getUsersGroups);
return view;
}
private class GroupInviteCustomAdapter extends ArrayAdapter<GroupInvite> {
private ArrayList<GroupInvite> groupInviteList;
public GroupInviteCustomAdapter(Context context, int textViewResourceId,
ArrayList<GroupInvite> groupInviteList) {
super(context, textViewResourceId, groupInviteList);
this.groupInviteList = new ArrayList<>();
this.groupInviteList.addAll(groupInviteList);
}
private class ViewHolder {
TextView inviteSent;
CheckBox checkBox;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
Log.v("ConvertView", String.valueOf(position));
if (convertView == null) {
LayoutInflater vi = (LayoutInflater) getActivity().getSystemService(
Context.LAYOUT_INFLATER_SERVICE);
convertView = vi.inflate(R.layout.event_invites_groups, null);
holder = new ViewHolder();
holder.checkBox = (CheckBox) convertView.findViewById(R.id.checkBox1); // here it is
holder.inviteSent = (TextView) convertView.findViewById(R.id.invite_already_sent);
convertView.setTag(holder);
holder.checkBox.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
CheckBox cb = (CheckBox) v;
GroupInvite groupInvited = (GroupInvite) cb.getTag();
Toast.makeText(getActivity(),
"Clicked on Checkbox: " + cb.getText() +
" is " + cb.isChecked(),
Toast.LENGTH_LONG).show();
groupInvited.setSelected(cb.isChecked());
}
});
} else {
holder = (ViewHolder) convertView.getTag();
}
GroupInvite groupInvite = groupInviteList.get(position);
holder.checkBox.setText(groupInvite.getName());
holder.checkBox.setChecked(groupInvite.isSelected());
holder.checkBox.setTag(groupInvite);
// Check if already invited, if so, should remove
if (groupInvite.isInvitedAlready() == true) {
holder.checkBox.setTextColor(Color.GRAY);
holder.checkBox.setClickable(false);
holder.inviteSent.setText("Invite Already Sent");
} else {
holder.inviteSent.setText("");
}
return convertView;
}
}
}
答案 0 :(得分：0)
将以下代码块移到getUsersGroups = new ValueEventListener（）
之外 dataAdapter = new GroupInviteCustomAdapter(getActivity(),
R.layout.event_invites_groups, mUsersGroups);
ListView listView = (ListView) getActivity().findViewById(R.id.listView1);
// Assign adapter to ListView
listView.setAdapter(dataAdapter);
dataAdapter.notifyDataSetChanged();
ValueEventListener（）仅执行覆盖方法。我的猜测是上面的代码永远不会运行。请尝试并告诉我它是否有效。如果它不会进一步调试。