android - 排序在我的应用程序的领域数据库中不起作用

Question

我是领域数据库的新手。我在领域数据库中完成了添加和获取数据。但是，我无法排序（升序和降序）。我的代码在列表视图中显示项目。Listview 包含 5 个列表，每个列表包含 4 个字段（姓名、年龄、技能和日期）。如果我对（升序）名称进行排序，需要在 5 个列表中升序。我的代码不起作用我在这里发布我的代码，

 private void Ascending_order() {

    realm.beginTransaction();


  RealmResults<Employee> result = realm.where(Employee.class)
            .sort("name", Sort.ASCENDING).findAll();
    realm.copyFromRealm(result);
    realm.commitTransaction();
    employeedetailadapter.notifyDataSetChanged();
}

适配器类：

  public class EmployeeDetailAdapter extends BaseAdapter {

private ArrayList<Employee>employeeDetaillists = new ArrayList<>();
private Context c;
private LayoutInflater inflater;
private OnItemClick mCallback;
private SimpleDateFormat df = new SimpleDateFormat("dd/mm/yyyy");



public EmployeeDetailAdapter(Context c,ArrayList<Employee> employeeDetaillists, OnItemClick listener) {
    this.employeeDetaillists = employeeDetaillists;
this.c= c;
    inflater = (LayoutInflater) c.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    this.mCallback = listener;

}

@Override
public int getCount() {
    return employeeDetaillists.size();
}

@Override
public Object getItem(int position) {
    return employeeDetaillists.get(position);
}

@Override
public long getItemId(int position) {
    return 0;
}

@Override
public View getView(final int position, View convertView, ViewGroup parent) {
    View v = convertView;
Holder holder;

if (v==null){
    v= (View) inflater.inflate(R.layout.list_single_item,null);
    holder = new Holder();
    holder.tvPersonName = (TextView) v.findViewById(R.id.tvPersonName);
    holder.tvPersonAge = (TextView) v.findViewById(R.id.tvPersonAge);
    holder.tvPersonSkill = (TextView) v.findViewById(R.id.tvPersonSkill);
    holder.ivEditPesonDetail=(ImageView)v.findViewById(R.id.ivEditPesonDetail);
    holder.tvPersondate=(TextView)v.findViewById(R.id.tvPersondate);
    holder.ivDeletePerson=(ImageView)v.findViewById(R.id.ivDeletePerson);
    v.setTag(holder);
}else{
    holder = (Holder) v.getTag();
}
holder.tvPersonName.setText(employeeDetaillists.get(position).getName());
holder.tvPersonAge.setText(employeeDetaillists.get(position).getAge());
holder.tvPersonSkill.setText(employeeDetaillists.get(position).getSkill());
    String strDate = df.format(employeeDetaillists.get(position).getSdate());
holder.tvPersondate.setText(strDate);

holder.ivDeletePerson.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        Delete(employeeDetaillists.get(position).getName(),position);

    }
});

return v;
}

private void Delete(String name, int position) {
    mCallback.onClickdelete(name, position);
}

public void updateData(RealmResults<Employee> result) {

}


class Holder {
    TextView tvPersonName, tvPersonAge, tvPersonSkill,tvPersondate;
    ImageView ivDeletePerson, ivEditPesonDetail;
}

}

标签： androidrealmrealm-mobile-platformrealm-database

Answer 1

您的代码不会更改 db. 你只是得到排序的项目，但不使用它们。

realm.copyFromRealm(result); // this line does nothing
realm.commitTransaction(); // this one too, because you change nothing
employeedetailadapter.notifyDataSetChanged(); // you data is the same, so this line also useless here

要查看已排序的数据，您应该RealmResults在适配器中使用。使用这种方法，您的列表始终会排序，即使在添加新项目之后也是如此。但请注意：您的适配器应该扩展RealmRecyclerViewAdapter.

您应该在创建适配器之前运行此代码并result在适配器内部使用：

RealmResults<Employee> result = realm.where(Employee.class)
        .sort("name", Sort.ASCENDING).findAll();

---

您也可以尝试手动更新适配器的数据。

private void Ascending_order() {
    RealmResults<Employee> result = realm.where(Employee.class)
            .sort("name", Sort.ASCENDING).findAll();
    employeedetailadapter.updateData(result); // update data inside adapter before calling `notifyDataSetChanged`
    employeedetailadapter.notifyDataSetChanged();
 }

您需要updateData自己创建方法：

public void updateData(RealmResults<Employee> result) {
    employeeDetaillists = new ArrayList<Employee>(result);
}