我想使用自定义适配器在ListView中显示来自Firebase列表的用户聊天。但不知怎的，它不起作用。当我尝试查看logcat中的数据时，我收到了响应，但是当我将列表传递给CustomAdapter时，它在ListView中不显示任何内容。有什么问题？
我的适配器：
public class ChatAdapter extends ArrayAdapter<String> {
private Activity context;
private List<Chats> chatsList = new ArrayList<>();
public ChatAdapter(Activity Context, List<Chats> chatsList) {
super(Context, R.layout.abc_main_chat_item);
this.context = Context;
this.chatsList = chatsList;
}
@Override
public View getView(final int position, final View convertView, ViewGroup parent) {
LayoutInflater inflater = context.getLayoutInflater();
View listViewItem = inflater.inflate(R.layout.abc_main_chat_item, null, true);
TextView tvusername = (TextView) listViewItem.findViewById(R.id.group_name);
TextView tvuid = (TextView) listViewItem.findViewById(R.id.useruid);
TextView tvlastmessage = (TextView) listViewItem.findViewById(R.id.latestMessage);
TextView tvlastmessagetime = (TextView) listViewItem.findViewById(R.id.latestMessageTime);
ImageView ivphoto = (ImageView) listViewItem.findViewById(R.id.profileImg);
tvusername.setText(chatsList.get(position).getUsername());
tvlastmessage.setText(chatsList.get(position).getLastMessage());
tvlastmessagetime.setText(chatsList.get(position).getLastMessageTime());
tvuid.setText(chatsList.get(position).getUseruid());
Picasso.with(getContext()).load(chatsList.get(position).getPhotoURL()).placeholder(R.drawable.ic_person_grey_round).into(ivphoto);
listViewItem.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent i = new Intent(context, Chat_Room.class);
i.putExtra("room_name", chatsList.get(position).getUsername());
i.putExtra("room_uid", chatsList.get(position).getUseruid());
context.startActivity(i);
}
});
listViewItem.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
final Dialog dialog = new Dialog(context);
dialog.setContentView(R.layout.abcd_listview_alertdia_layout);
ArrayList<String> list_of_chats = new ArrayList<>();
final ArrayAdapter<String> arrayAdapter;
arrayAdapter = new ArrayAdapter<String>(context, android.R.layout.simple_list_item_1, list_of_chats);
list_of_chats.add(0, "Chatverlauf mit "+ chatsList.get(position).getUsername()+" löschen?");
list_of_chats.add(1, "Profil von "+chatsList.get(position).getUsername()+" anschauen");
arrayAdapter.notifyDataSetChanged();
final ListView lv = (ListView) dialog.findViewById(R.id.lv);
lv.setAdapter(arrayAdapter);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, final int position2, long id) {
if (position2 == 0) {
dialog.dismiss();
AlertDialog.Builder alert = new AlertDialog.Builder(context);
alert.setTitle("Chatverlauf mit "+chatsList.get(position).getUsername()+" löschen?")
.setMessage("Du kannst das Löschen nicht rückgängig machen. Bist du dir sicher?")
.setNegativeButton("Abbrechen", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
})
.setPositiveButton("OK", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
FirebaseDatabase.getInstance().getReference().child("chats").child("userchats").child(FirebaseAuth.getInstance().getCurrentUser().getUid()).child(chatsList.get(position).getUseruid()).setValue(null);
FirebaseDatabase.getInstance().getReference().child("chats").child("users").child(FirebaseAuth.getInstance().getCurrentUser().getUid()).child("messages").child(chatsList.get(position).getUseruid()).setValue(null);
}
}).setCancelable(true)
.show();
lv.setAdapter(arrayAdapter);
arrayAdapter.notifyDataSetChanged();
}
if (position2 == 1) {
Intent intent = new Intent(context, ViewContact.class);
intent.putExtra("useruid", chatsList.get(position).getUseruid());
context.startActivity(intent);
}
}
});
dialog.show();
return true;
}
});
ivphoto.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
final Dialog dialog = new Dialog(context);
dialog.setContentView(R.layout.abcd_profile_pic_dialog_layout);
ImageView imageView = (ImageView) dialog.findViewById(R.id.alertImage);
TextView textView = (TextView)dialog.findViewById(R.id.alertdialogtv);
ImageView message = (ImageView)dialog.findViewById(R.id.alertMessage);
ImageView profile = (ImageView)dialog.findViewById(R.id.alertProfile);
profile.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(context, ViewContact.class);
intent.putExtra("useruid", chatsList.get(position).getUseruid());
context.startActivity(intent);
dialog.dismiss();
}
});
message.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(getContext(), Chat_Room.class);
intent.putExtra("room_name", chatsList.get(position).getUsername());
intent.putExtra("room_uid", chatsList.get(position).getUseruid());
context.startActivity(intent);
}
});
Picasso.with(getContext()).load(chatsList.get(position).getPhotoURL()).placeholder(R.drawable.ic_person_grey_round).into(imageView);
textView.setText(chatsList.get(position).getUsername());
dialog.setCancelable(true);
dialog.show();
}
});
return listViewItem;
}
...
}
这就是我获取List的数据的方式：
FirebaseDatabase.getInstance().getReference().child("chats").child("userchats").child(myUiD).addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
List<chatapp.chatapp2.Chats.Chats> chatsList = new ArrayList<chatapp.chatapp2.Chats.Chats>();
for(DataSnapshot snapshot : dataSnapshot.getChildren()){
chatapp.chatapp2.Chats.Chats chats = new chatapp.chatapp2.Chats.Chats();
chats.setUsername(snapshot.child("roomname").getValue().toString());
chats.setPhotoURL(snapshot.child("photoURL").getValue().toString());
chats.setLastMessage(snapshot.child("lastMessage").getValue().toString());
chats.setLastMessageTime(snapshot.child("lastMessageTime").getValue().toString());
chats.setUseruid(snapshot.child("userUiD").getValue().toString());
chatsList.add(chats);
Log.d("CHATS", chats.getUsername());
Log.d("CHATS", chats.getUseruid());
}
ChatAdapter chatAdapter = new ChatAdapter(getActivity(), chatsList);
chatAdapter.notifyDataSetChanged();
listView.setAdapter(chatAdapter);
listView.setVisibility(View.VISIBLE);
}
...
});
答案 0 :(得分：0)
我真的不知道它为什么不起作用，但我找到了解决方案：
您必须覆盖getCount方法，如下所示：
@Override
public int getCount() {
return chatsList == null ? 0 : chatsList.size();
}
我不知道它做了什么，但它有效:) :)