android中自定义ArrayAdapter中的自定义getFilter [英] Custom getFilter in custom ArrayAdapter in android

问题描述

我在自定义 arrayAdapter 中实现自定义 getFilter 时遇到问题.其实我不知道如何实现它.尝试了各种代码，但仍然没有运气.这是我的自定义阵列适配器.

I am having trouble implementing custom getFilter in custom arrayAdapter. Actually I have no idea how to implement it. Tried various codes but still no luck. Here is my custom array adapter.

package com.test.FilterableList.Adapters;

import java.util.ArrayList;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

import com.test.FilterableList.Models.ListTO;
import com.test.FilterableList.R;

import android.widget.Filterable;


public class FilterableAdapter extends ArrayAdapter<ListTO> implements Filterable {

    // declaring our ArrayList of items
    public ArrayList<ListTO> objects;

    /* here we must override the constructor for ArrayAdapter
    * the only variable we care about now is ArrayList<Item> objects,
    * because it is the list of objects we want to display.
    */
    public FilterableAdapter(Context context, int textViewResourceId, ArrayList<ListTO> objects) {
        super(context, textViewResourceId, objects);
        this.objects = objects;
    }

    /*
     * we are overriding the getView method here - this is what defines how each
     * list item will look.
     */
    public View getView(int position, View convertView, ViewGroup parent){

        // assign the view we are converting to a local variable
        View v = convertView;

        // first check to see if the view is null. if so, we have to inflate it.
        // to inflate it basically means to render, or show, the view.
        if (v == null) {
            LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            v = inflater.inflate(R.layout.list_item, null);
        }

        /*
         * Recall that the variable position is sent in as an argument to this method.
         * The variable simply refers to the position of the current object in the list. (The ArrayAdapter
         * iterates through the list we sent it)
         *
         * Therefore, i refers to the current Item object.
         */
        ListTO i = objects.get(position);

        if (i != null) {

            // This is how you obtain a reference to the TextViews.
            // These TextViews are created in the XML files we defined.

            TextView tt = (TextView) v.findViewById(R.id.list_name);
            if (tt != null){
                tt.setText(i.FileName);
            }



        }

        // the view must be returned to our activity
        return v;

    }
}

这里是 ListTO 类.

And Here is the ListTO class.

package com.test.FilterableList.Models;

public class ListTO {

    public int Id;
    public String FileName;
    public String FileUri;

    public ListTO(int id, String fileName, String fileUri) {

        Id = id;
        FileName = fileName;
        FileUri = fileUri;

    }

}

这是布局.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="@drawable/blacklikenbackground"
    tools:context=".AllListActivity" >

    <EditText
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Search"
        android:id="@+id/inputSearch"
        />


    <ListView
        android:id="@+id/test_list"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
    </ListView>

</LinearLayout>

这里的搜索关键字来自inputSearch"EditText.

Here the search keyword comes from "inputSearch" EditText.

这是文本更改的侦听器.

Here's the text changed listener.

 inputSearch.addTextChangedListener(new TextWatcher() {

                    @Override
                    public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) {
                        // When user changed the Text
                      //  Toast.makeText(getActivity(), cs.toString(), Toast.LENGTH_LONG).show();
                        m_adapter.getFilter().filter(cs);
                    }

                    @Override
                    public void beforeTextChanged(CharSequence arg0, int arg1, int arg2,
                                                  int arg3) {
                        // TODO Auto-generated method stub

                    }

                    @Override
                    public void afterTextChanged(Editable arg0) {
                        // TODO Auto-generated method stub
                    }
                });

谢谢.

推荐答案

您遇到问题，主要是因为您使用的是自定义对象.如果您将 String 或 int 值传递给数组适配器，则它知道如何对其进行过滤.但是如果您通过自定义对象默认过滤器实现就不必知道如何处理.

You are having problem, mainly because you are using custom object. If you pass a String or int value to array adapter its know how to filter it. But if you pass custom object default filter implementation have to no idea how to deal with that.

虽然不清楚您要在过滤器中做什么，但我建议您按照以下步骤操作.

Although it is not clear what you are trying to do in your filter i recommend you following steps.

1. ListTO 的正确实现，虽然它与你现在的目标无关
2. 实现自定义过滤器
3. 返回过滤器

1. Proper implementation of ListTO, although it has nothing to do with your goal right now
2. Implement custom filter
3. return your filter

实现自定义过滤器

您必须做的第一件事是从您的阵列适配器中实现 Filterable.

First thing you have to do is, implements Filterable from your array adapter.

第二，提供你的Filter

Filter myFilter = new Filter() {
        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
         FilterResults filterResults = new FilterResults();   
         ArrayList<ListTO> tempList=new ArrayList<ListTO>();
         //constraint is the result from text you want to filter against. 
         //objects is your data set you will filter from
         if(constraint != null && objects!=null) {
             int length=objects.size();
             int i=0;
                while(i<length){
                    ListTO item=objects.get(i);
                    //do whatever you wanna do here
                    //adding result set output array     

                    tempList.add(item);

                    i++;
                }
                //following two lines is very important
                //as publish result can only take FilterResults objects
                filterResults.values = tempList;
                filterResults.count = tempList.size();
          }
          return filterResults;
      }

      @SuppressWarnings("unchecked")
      @Override
      protected void publishResults(CharSequence contraint, FilterResults results) {
          objects = (ArrayList<ListTO>) results.values;
          if (results.count > 0) {
           notifyDataSetChanged();
          } else {
              notifyDataSetInvalidated();
          }  
      }
     };

最后一步，

@Override
     public Filter getFilter() {
        return myFilter;
    }

这篇关于android中自定义ArrayAdapter中的自定义getFilter的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！