如何使用 BaseAdapter 刷新带有文本和图像的列表视图？

Posted 2023-04-19

【中文标题】如何使用 BaseAdapter 刷新带有文本和图像的列表视图？

【英文标题】：How do I refresh a listview with text and image using BaseAdapter?

【发布时间】：2021-09-28 14:32:34

【问题描述】：

我需要一些帮助来刷新我的列表视图数据。

我按照this 教程制作了一个列表视图。

这里是：

ListAdapter.java:

package com.sanktips.customlistviewexample;

import android.content.Context;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.ArrayList;


public class ListAdapter extends BaseAdapter 

    Context context;
    private final String [] values;
    private final String [] numbers;
    private final int [] images;

    public ListAdapter(Context context, String [] values, String [] numbers, int [] images)
        //super(context, R.layout.single_list_app_item, utilsArrayList);
        this.context = context;
        this.values = values;
        this.numbers = numbers;
        this.images = images;
    

    @Override
    public int getCount() 
        return values.length;
    

    @Override
    public Object getItem(int i) 
        return i;
    

    @Override
    public long getItemId(int i) 
        return i;
    

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) 


        ViewHolder viewHolder;

        final View result;

        if (convertView == null) 

            viewHolder = new ViewHolder();
            LayoutInflater inflater = LayoutInflater.from(context);
            convertView = inflater.inflate(R.layout.single_list_item, parent, false);
            viewHolder.txtName = (TextView) convertView.findViewById(R.id.aNametxt);
            viewHolder.txtVersion = (TextView) convertView.findViewById(R.id.aVersiontxt);
            viewHolder.icon = (ImageView) convertView.findViewById(R.id.appIconIV);

            result=convertView;

            convertView.setTag(viewHolder);
         else 
            viewHolder = (ViewHolder) convertView.getTag();
            result=convertView;
        

        viewHolder.txtName.setText(values[position]);
        viewHolder.txtVersion.setText("Version: "+numbers[position]);
        viewHolder.icon.setImageResource(images[position]);

        return convertView;
    

    private static class ViewHolder 

        TextView txtName;
        TextView txtVersion;
        ImageView icon;

    

MainActivity.java 文件：

package com.sanktips.customlistviewexample;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity 

    
    ListView lView;

    ListAdapter lAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

int[] images = R.drawable.alpha, R.drawable.beta, R.drawable.cupcake, R.drawable.donut, R.drawable.eclair, R.drawable.froyo, R.drawable.gingerbread, R.drawable.honeycomb, R.drawable.icecreamsandwich, R.drawable.jellybean, R.drawable.kitkat, R.drawable.lollipop, R.drawable.marshmallow, R.drawable.nougat;

    String[] version = "Android Alpha", "Android Beta", "Android Cupcake", "Android Donut", "Android Eclair", "Android Froyo", "Android Gingerbread", "Android Honeycomb", "Android Ice Cream Sandwich", "Android JellyBean", "Android Kitkat", "Android Lollipop", "Android Marshmallow", "Android Nougat";

    String[] versionNumber = "1.0", "1.1", "1.5", "1.6", "2.0", "2.2", "2.3", "3.0", "4.0", "4.1", "4.4", "5.0", "6.0", "7.0";

        lView = (ListView) findViewById(R.id.androidList);

        lAdapter = new ListAdapter(MainActivity.this, version, versionNumber, images);

        lView.setAdapter(lAdapter);

        lView.setOnItemClickListener(new AdapterView.OnItemClickListener() 
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) 
                
                Toast.makeText(MainActivity.this, version[i]+" "+versionNumber[i], Toast.LENGTH_SHORT).show();

            
        );

    

由于某种原因，当我在列表适配器上调用 notifySetDataChanged 时，它不起作用。

我也尝试重新创建适配器，但它没有更新。

有人可以帮我如何正确刷新列表视图吗？

【问题讨论】：

您在哪里刷新代码中的适配器？您是否更新了数组中的任何值以调用该刷新？

【参考方案1】：

当您调用notifyDataSetChanged() 时，您必须提供一个新的数据源。如果您只调用notifyDataSetChanged() 而没有任何新数据，您的列表将不会刷新。因此，在调用notifyDataSetChanged() 之前，请尝试更新您在构造函数中传递的数组数据。但是在适配器内部添加更新功能是一个好习惯。此外，您可以使用 ArrayList 代替简单的数组。