我正在创建一个用于查找附近献血者的应用程序。在这个应用程序中，我使用三个片段进行滑动导航。在一个片段中，显示了可用的捐赠者列表，但是我想通过单击特定的血型来从菜单列表中更改列表。第一个列表是，但是当我单击项目时，它什么也没显示。
Java代码：
public class DonorsFragment extends Fragment {
SwipeMenuListView listView;
FirebaseListAdapter adapter;
TextView fullName,bloodGroup,gender,age,address;
Query query;
View rootView;
FirebaseListOptions<DonorAdapterClass> options;
public DonorsFragment() {
// Required empty public constructor
}
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
rootView =inflater.inflate(R.layout.fragment_donors, container, false);
listView = rootView.findViewById(R.id.listview);
Toast.makeText(getActivity(),"oncreateview",Toast.LENGTH_SHORT).show();
query =FirebaseDatabase.getInstance().getReference().child("Users");
setQuery(query);
SwipeMenuCreator creator = new SwipeMenuCreator() {
@Override
public void create(SwipeMenu menu) {
// create "delete" item
SwipeMenuItem deleteItem = new SwipeMenuItem(getActivity());
// set item background
deleteItem.setBackground(new ColorDrawable(Color.rgb(0xF9,
0x3F, 0x25)));
// set item width
deleteItem.setWidth(170);
// set a icon
deleteItem.setIcon(R.drawable.ic_phone);
// add to menu
menu.addMenuItem(deleteItem);
}
};
listView.setMenuCreator(creator);
listView.setOnMenuItemClickListener(new SwipeMenuListView.OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(int position, SwipeMenu menu, int index) {
switch (index) {
case 0:
// open
Toast.makeText(getActivity(),"Item Clicked",Toast.LENGTH_SHORT).show();
break;
}
// false : close the menu; true : not close the menu
return false;
}
});
// Inflate the layout for this fragment
return rootView;
}
@Override
public void onStart() {
super.onStart();
adapter.startListening();
}
@Override
public void onStop() {
super.onStop();
adapter.stopListening();
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
super.onCreateOptionsMenu(menu, inflater);
inflater.inflate(R.menu.blood_group_menu,menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()){
case R.id.a_pos: {
Toast.makeText(getActivity(),"A+",Toast.LENGTH_SHORT).show();
query=FirebaseDatabase.getInstance().getReference().child("Users").orderByChild("canGive_A_Pos").equalTo("yes");
setQuery(query);
break;
}
case R.id.a_neg: {
Toast.makeText(getActivity(),"A-",Toast.LENGTH_SHORT).show();
query=FirebaseDatabase.getInstance().getReference().child("Users").orderByChild("canGive_A_Neg").equalTo("yes");
setQuery(query);
break;
}
case R.id.b_pos: {
Toast.makeText(getActivity(),"B+",Toast.LENGTH_SHORT).show();
query=FirebaseDatabase.getInstance().getReference().child("Users").orderByChild("canGive_B_Pos").equalTo("yes");
setQuery(query);
break;
}
case R.id.b_neg: {
Toast.makeText(getActivity(),"B-",Toast.LENGTH_SHORT).show();
query=FirebaseDatabase.getInstance().getReference().child("Users").orderByChild("canGive_B_Neg").equalTo("yes");
setQuery(query);
break;
}
case R.id.ab_pos: {
Toast.makeText(getActivity(),"AB+",Toast.LENGTH_SHORT).show();
query=FirebaseDatabase.getInstance().getReference().child("Users").orderByChild("canGive_A_Pos").equalTo("yes");
setQuery(query);
break;
}
case R.id.ab_neg: {
Toast.makeText(getActivity(),"AB-",Toast.LENGTH_SHORT).show();
query=FirebaseDatabase.getInstance().getReference().child("Users");
setQuery(query);
break;
}
case R.id.o_pos: {
Toast.makeText(getActivity(),"O+",Toast.LENGTH_SHORT).show();
query=FirebaseDatabase.getInstance().getReference().child("Users").orderByChild("canGive_O_Pos").equalTo("yes");
setQuery(query);
break;
}
case R.id.o_neg: {
Toast.makeText(getActivity(),"O-",Toast.LENGTH_SHORT).show();
query=FirebaseDatabase.getInstance().getReference().child("Users").orderByChild("canGive_O_Neg").equalTo("yes");
setQuery(query);
break;
}
case R.id.list_all: {
Toast.makeText(getActivity(),"All",Toast.LENGTH_SHORT).show();
query=FirebaseDatabase.getInstance().getReference().child("Users");
setQuery(query);
break;
}
}
return super.onOptionsItemSelected(item);
}
public void setQuery(Query query){
listView = rootView.findViewById(R.id.listview);
options = new FirebaseListOptions.Builder<DonorAdapterClass>()
.setLayout(R.layout.donor_list)
.setQuery(query,DonorAdapterClass.class)
.build();
adapter = new FirebaseListAdapter(options) {
@Override
protected void populateView(@NonNull View v, @NonNull Object model, int position) {
DonorAdapterClass donors = (DonorAdapterClass) model;
if(donors.getIsDonor().toString().equals("yes")){
fullName = v.findViewById(R.id.fullName_list);
bloodGroup = v.findViewById(R.id.bloodGroup_list);
gender = v.findViewById(R.id.gender_lis);
address = v.findViewById(R.id.address_list);
age = v.findViewById(R.id.age_list);
fullName.setText(donors.getFullName().toString());
bloodGroup.setText(donors.getBloodGroup().toString());
gender.setText(donors.getGender().toString());
address.setText(donors.getAddress().toString());
age.setText(donors.getAge().toString());
}
}
};
listView.setAdapter(adapter);
}
}
所有firebase查询和适配器都在setQuery（）方法中设置..当从onCreateView（）调用时它正在工作...但是当从onOptionsItemSelected中的切换案例调用它时，它什么也不显示，并且以前的列表视图也隐藏
先谢谢了：）
答案 0 :(得分：0)
这是我几个世纪以来的第一个答案，请耐心等待。这不是答案，而只是指向解决之道的指针。
在以下几点设置一个断点
运行该应用。使用调试器附加进程。现在，当您从选项中单击“ A +”时，它是从服务器获得响应还是引发异常？