我有一个自定义列表视图，其中包含3个textview for Name，Unique id和Number of Absent以及1个用于删除每个列表项的图像按钮。我试图对缺席的数量进行排序，但排序却有所不同。我在互联网上看到比较器，我认为这是我的问题的解决方案，但我不知道如何使用它。希望有人在这里帮助我。
这就是我在3 ArrayList中添加值的方法（mUid表示唯一ID，MFullname表示名称，mStatus表示缺少数量）
pagod = FirebaseDatabase.getInstance().getReference().child("users").child("teacher").child(user.getUid().toString().trim()).child("class").child(aba).child(message).child("Listofstudents");
pagod.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot child : dataSnapshot.getChildren()) {
String userid = child.child("userid").getValue().toString().trim();
String name = child.child("name").getValue().toString().trim();
mUid.add(userid);
mFullname.add(name);
//studentlist.invalidateViews();
//adapter.notifyDataSetChanged();
if (dataSnapshot.child(userid).child("attendance").exists()) {
pagodnapagod = FirebaseDatabase.getInstance().getReference();
Query query = pagodnapagod.child("users").child("teacher").child(user.getUid().toString().trim()).child("class").child(aba).child(message).child("Listofstudents").child(userid).child("attendance").child("finals").orderByChild("status").equalTo("absent");
query.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()) {
String numberOfStudent ="Number of Absent: "+dataSnapshot.getChildrenCount();
//Toast.makeText(MyClassesActivity.this, numberOfStudent, Toast.LENGTH_SHORT).show();
mStatus.add(numberOfStudent);
//Collections.sort(mStatus, Collections.reverseOrder());
adapters.notifyDataSetChanged();
progressDialog.dismiss();
} else {
String numberOfStudent = "Number of Absent: 0";
mStatus.add(numberOfStudent);
//Collections.sort(mStatus, Collections.reverseOrder());
adapters.notifyDataSetChanged();
progressDialog.dismiss();
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
} else {
String numberOfStudent = "Number of Absent: 0";
mStatus.add(numberOfStudent);
//Collections.sort(mStatus, Collections.reverseOrder());
adapters.notifyDataSetChanged();
progressDialog.dismiss();
}
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
这是我的自定义适配器。
class Adapters extends BaseAdapter implements Filterable {
private Context context;
private int resource;
private int ids;
private ArrayList arrayList;
private List<String> originalData=null;
private List<String>filteredData=null;
private List<String> userId;
private List<String> status;
private FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
private Adapters.ItemFilter mFilter = new Adapters.ItemFilter();
private LayoutInflater inflater;
public Adapters(Context context, int resource, int id, ArrayList arrayList, ArrayList userId, ArrayList status){
this.context = context;
this.resource = resource;
this.ids = id;
this.arrayList = arrayList;
this.filteredData = arrayList ;
this.originalData = arrayList ;
this.userId = userId;
this.status = status;
inflater = LayoutInflater.from(context);
}
public int getCount() {
return filteredData.size();
}
public Object getItem(int position) {
return filteredData.get(position);
}
public long getItemId(int position) {
return position;
}
// Hold views of the ListView to improve its scrolling performance
private class ViewHolder {
public TextView type;
public TextView uid;
public TextView count;
public ImageButton removeButton;
}
public View getView(final int position, final View convertView, ViewGroup parent) {
View rowView = convertView;
// Inflate the list_item.xml file if convertView is null
if(rowView==null){
rowView = inflater.inflate(R.layout.listitem6, null);
rowView= inflater.inflate(resource, parent, false);
Adapters.ViewHolder viewHolder = new Adapters.ViewHolder();
viewHolder.type= (TextView) rowView.findViewById(R.id.txt);
viewHolder.uid= (TextView) rowView.findViewById(R.id.id);
viewHolder.count= (TextView) rowView.findViewById(R.id.count);
viewHolder.removeButton= (ImageButton) rowView.findViewById(btn_del);
rowView.setTag(viewHolder);
}
final String x = (String) arrayList.get(position);
final String y = arrayList.get(position).toString().trim();
// Set text to each TextView of ListView item
Adapters.ViewHolder holder = (Adapters.ViewHolder) rowView.getTag();
holder.type.setText(x);
holder.uid.setText(x);
holder.count.setText(x);
holder.removeButton.setBackgroundResource(R.drawable.deletes);
holder.removeButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(final View view) {
View parentRow = (View) view.getParent();
ListView listView = (ListView) parentRow.getParent();
final int position = listView.getPositionForView(parentRow);
TextView userId=(TextView) parentRow.findViewById(R.id.id);
TextView userName=(TextView) parentRow.findViewById(R.id.txt);
final String name = userName.getText().toString().trim();
final String uid = userId.getText().toString().trim();
//Toast.makeText(StudentListActivity.this, name +"\n" + uid, Toast.LENGTH_SHORT).show();
final AlertDialog.Builder builder2=new AlertDialog.Builder(context);
final View dialogView = inflater.inflate(R.layout.customdialog, null);
builder2.setView(dialogView);
final EditText input = (EditText) dialogView.findViewById(R.id.edit1);
final TextInputLayout inputs = (TextInputLayout) dialogView.findViewById(R.id.text_field);
TextWatcher watcher = new TextWatcher() {
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void afterTextChanged(Editable s) {
inputs.setErrorEnabled(false);
inputs.setError(null);
}
};
input.addTextChangedListener(watcher);
builder2.setTitle("Delete Class");
builder2.setMessage("Do you want to delete "+y+" from this class?");
builder2.setPositiveButton("ok", null);
builder2.setNegativeButton("cancel", null);
builder2.setIcon(R.drawable.deletes);
builder2.setCancelable(false);
final AlertDialog mAlertDialog = builder2.create();
mAlertDialog.setOnShowListener(new DialogInterface.OnShowListener() {
@Override
public void onShow(final DialogInterface dialog) {
Button a = mAlertDialog.getButton(AlertDialog.BUTTON_POSITIVE);
a.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// TODO Do something
if (input.getText().toString().equalsIgnoreCase("delete")) {
arrayList.remove(position);
notifyDataSetChanged();
Toast.makeText(view.getContext(), y + " has been deleted in this class", Toast.LENGTH_SHORT).show();
DatabaseReference mDatabase = FirebaseDatabase.getInstance().getReference().child("users").child("teacher").child(user.getUid().toString().trim()).child("class").child(aba).child(message).child("Listofstudents").child(uid);
mDatabase.setValue(null);
ref0 = FirebaseDatabase.getInstance().getReference();
ref0.child("usersclass").orderByChild("userid_classid").equalTo(uid+"-"+message).addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot child: dataSnapshot.getChildren()) {
String hello = child.getKey();
ref0.child("usersclass").child(hello).setValue(null);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
dialog.dismiss();
notifyDataSetChanged();
restartThis();
} else {
inputs.setError("Enter word DELETE");
}
}
});
Button b = mAlertDialog.getButton(AlertDialog.BUTTON_NEGATIVE);
b.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// TODO Do something
dialog.dismiss();
}
});
}
});
mAlertDialog.show();
}
});
holder.type.setText(filteredData.get(position));
holder.uid.setText(userId.get(position));
holder.count.setText(status.get(position));
return rowView;
}
public Filter getFilter() {
return mFilter;
}
private class ItemFilter extends Filter {
@Override
protected FilterResults performFiltering(CharSequence constraint) {
String filterString = constraint.toString().toLowerCase();
FilterResults results = new FilterResults();
final List<String> list = originalData;
int count = list.size();
final ArrayList<String> nlist = new ArrayList<String>(count);
String filterableString ;
for (int i = 0; i < count; i++) {
filterableString = list.get(i);
if (filterableString.toLowerCase().contains(filterString)) {
nlist.add(filterableString);
}
}
results.values = nlist;
results.count = nlist.size();
return results;
}
@SuppressWarnings("unchecked")
@Override
protected void publishResults(CharSequence constraint, FilterResults results) {
filteredData = (ArrayList<String>) results.values;
notifyDataSetChanged();
}
}
}