如何在 Android 中将多个 ArrayList 传递给 BaseAdapter？答案

【问题标题】：How to pass multiple ArrayList to BaseAdapter in Android?如何在 Android 中将多个 ArrayList 传递给 BaseAdapter？
【发布时间】：2017-12-06 06:31:14
【问题描述】：

我正在尝试将一些动态数据传递给BaseAdapter 以在listview 上显示它。（使用ArrayList），我当前的代码给了我以下错误：

错误：

error: cannot find symbol variable ArrayList
error: cannot find symbol variable String

指向这部分代码（ArrayList ）：

CustomAdapter customAdapter = new CustomAdapter(getApplicationContext(), ArrayList<String> NameArrayList, ArrayList<String> IconArrayList);

我检查了 Arraylist 的大小，发现 IconArrayList 和 NameArrayList 不为空，使用 int itemCount = IconArrayList.size();

但是，如果我将以下静态字符串数组传递给 Baseadapter，那么它将在 listview 上显示数据！

String NameArrayList[] = {"USA", "China", "australia", "Portugle", "Norway", "NewZealand"};
String IconArrayList[] = {"http://awebsite.com/icons/usa.png", "http://awebsite.com/icons/china.png", "http://awebsite.com/icons/australia.png", "http://awebsite.com/icons/portugle.png", "http://awebsite.com/icons/norway.png", "http://awebsite.com/icons/new_zealand.png"};

CustomAdapter customAdapter = new CustomAdapter(getApplicationContext(), NameArrayList, IconArrayList);

你们能帮我解决上述错误并成功将arraylist传递给baseAdapter以便显示它。提前致谢。

MainActivity.java：

import android.app.Activity;
import android.os.Bundle;
import android.widget.ListView;

import android.view.View;
import android.widget.AdapterView;
import android.widget.Toast;

import android.os.StrictMode;
import android.os.StrictMode.ThreadPolicy.Builder;

import java.io.InputStreamReader;

import java.net.URL;
import java.net.HttpURLConnection;
import java.io.OutputStream;
import java.io.BufferedReader;

import java.util.ArrayList;

public class MainActivity extends Activity {

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

        sendGetRequest();

     }


public String sendGetRequest() {

         String NEW_ICON = "icon";


        ArrayList<String> IconArrayList =new ArrayList<String>();
        ArrayList<String> NameArrayList =new ArrayList<String>();
        ArrayList<String> UrlArrayList =new ArrayList<String>();


        try {

            StrictMode.setThreadPolicy(new Builder().permitAll().build());

            HttpURLConnection myURLConnection = (HttpURLConnection) new URL("http://awebsite.com/test/test.php").openConnection();


            myURLConnection.setReadTimeout(60000);
            myURLConnection.setConnectTimeout(60000);
            myURLConnection.setRequestMethod("GET");
            myURLConnection.setUseCaches(false);
            myURLConnection.setDoInput(true);
            myURLConnection.setDoOutput(true);
            myURLConnection.setRequestProperty("Content-Type", "html");
            myURLConnection.setRequestProperty("User-Agent", "Dalvik/2.1.0 (Linux; U; Android 6.0;)");

            OutputStream os = myURLConnection.getOutputStream();

            os.close();

            myURLConnection.connect();

            BufferedReader in = new BufferedReader(new InputStreamReader(myURLConnection.getInputStream()));


            StringBuffer sb = new StringBuffer();

            String line;


            while ((line = in.readLine()) != null) {

                sb.append(line);
                sb.append("\\n");
            }
            in.close();



            String linesArray[] = sb.toString().split("#MYLIST:");

            for (int i = 0; i < linesArray.length; i++) {
                String currLine = linesArray[i];


                String[] dataArray = currLine.split(",");

                if (dataArray[0].contains(NEW_ICON)) {

                   String s =dataArray[0];

                    s = s.substring(s.indexOf("(") + 1);
                    s = s.substring(0, s.indexOf(")"));


                    IconArrayList.add(s);



                    if (dataArray[1].contains("http://")) {
                        String[] split = dataArray[1].split("http://");
                        String name = split[0];
                        String url = split[1];
                        url ="http://"+url;

                        //adding name and url to arraylist
                        NameArrayList.add(name);
                        UrlArrayList.add(url);
                      }


                }



            }// end of for loop

            //showing array list total
            int itemCount = IconArrayList.size();
            int itemCount2 = NameArrayList.size();
            int itemCount3 = UrlArrayList.size();


            ListView simpleList;
            simpleList = (ListView) findViewById(R.id.simpleListView);
            CustomAdapter customAdapter = new CustomAdapter(getApplicationContext(), ArrayList<String> NameArrayList, ArrayList<String> IconArrayList);
            simpleList.setAdapter(customAdapter);


        } catch (Exception e) {

        }
        return null;

    }

基础适配器：

public class CustomAdapter extends BaseAdapter {
    Context context;
    String countryList[];

    String flags[];

    LayoutInflater inflter;

    public CustomAdapter(Context applicationContext, String[] countryList, String[] flags) {
        this.context = context;
        this.countryList = countryList;
        this.flags = flags;
        inflter = (LayoutInflater.from(applicationContext));
    }

    @Override
    public int getCount() {
        return countryList.length;
    }

    @Override
    public Object getItem(int i) {
        return null;
    }

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

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        view = inflter.inflate(R.layout.activity_listview, null);
        TextView country = (TextView) view.findViewById(R.id.textView);
        ImageView icon = (ImageView) view.findViewById(R.id.icon);
        country.setText(countryList[i]);

        Picasso.with(view.getContext())
                .load(flags[i])
                //.resize(50,50)
                .into(icon);

        return view;
    }
}

【问题讨论】：

标签： android listview arraylist baseadapter

【解决方案1】：

您正在发送 WRONG TYPE

CustomAdapter customAdapter = new CustomAdapter(getApplicationContext(), ArrayList<String> NameArrayList, ArrayList<String> IconArrayList);

会的

 CustomAdapter customAdapter = new CustomAdapter(getApplicationContext(),  NameArrayList,  IconArrayList);

所以，你的 Constructor 将是

ArrayList<String> countryList;
ArrayList<String> flags;

public CustomAdapter(Context applicationContext,ArrayList<String> countryListOBJ, ArrayList<String> flagsOBJ) {
        this.context = context;
        this.countryList = countryListOBJ;
        this.flags = flagsOBJ;
        inflter = (LayoutInflater.from(applicationContext));
    }

那么

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

【讨论】：

感谢所有回复。 IntelliJ Amiya 我试过你的帖子，但我得到了 3 个新错误，都指向自定义适配器内的行！错误：找不到符号可变长度错误：需要数组，但找到了 ArrayList 错误：需要数组，但找到了 ArrayList
@user1788736 使用countryList.size() 而不是countryList.length
@user1788736 打印countryList.size() 。检查结果。
非常感谢您帮助我，我接受了您的回答。现在数据显示在列表视图上:-)
如果我想通过单击 listview 项目来显示 toast 如何引用 simpleList.setOnItemClickListener 中的 listview 行项目？

【解决方案2】：

这不是将多个属性传递给任何类的方法。您应该使用 POJO 类来代替它。下面是一个例子。

class CountryModel{
    public String countryName;
    public String countryFlag;

    public CountryModel(String countryName, String countryFlag) {
        this.countryName = countryName;
        this.countryFlag = countryFlag;
    }
}

然后将你的数据解析成这个模型对象的集合。下面是一个例子。

 ArrayList<CountryModel> countryList=new ArrayList<>();
 countryList.add(new CountryModel("Norway","NorwayflagUrl"));
 countryList.add(new CountryModel("Iceland","IcelandflagUrl"));
 countryList.add(new CountryModel("Denmark","DenmarkflagUrl"));

然后设置适配器。在这种情况下，您需要修改您的适配器。

ListView simpleList = (ListView) findViewById(R.id.simpleListView);
        CustomAdapter customAdapter = new CustomAdapter(getApplicationContext(), countryList);
        simpleList.setAdapter(customAdapter);

您可以如下修改您的适配器。

 public class CustomAdapter extends BaseAdapter {
    Context context;
   ArrayList<CountryModel> countryList;

    LayoutInflater inflter;

    public CustomAdapter(Context applicationContext, ArrayList<CountryModel> countryList) {
        this.context = context;
        this.countryList = countryList;
        inflter = (LayoutInflater.from(applicationContext));
    }

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

    @Override
    public Object getItem(int i) {
        return countryList.get(i);
    }

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

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        view = inflter.inflate(R.layout.activity_listview, null);
        TextView country = (TextView) view.findViewById(R.id.textView);
        ImageView icon = (ImageView) view.findViewById(R.id.icon);
        country.setText(countryList.get(i).countryName);

        Picasso.with(view.getContext())
                .load(countryList.get(i).countryFlag)
                //.resize(50,50)
                .into(icon);
        return view;
    }
}

【讨论】：

【解决方案3】：

1. 您在CustomAdapter 的constructor 上使用了字符串数组。但是你从Activity 类中传递了ArrayList<String>。所以在CustomAdapter上制作这些ArrayList-

    private ArrayList<String> NameArrayList;
    private ArrayList<String> IconArrayList;

    public CustomAdapter(getApplicationContext(), ArrayList<String> NameArrayList, ArrayList<String> IconArrayList) {
        this.NameArrayList= NameArrayList;
        this.IconArrayList= IconArrayList;
        inflter = (LayoutInflater.from(applicationContext));
    }

2.您正在通过MainThread 上的API 调用从服务器获取数据。尝试将此部分保留在单独的线程上以获得更好的性能（有时您不会从服务器获取任何数据，因为连接速度慢或处理时间长）。并使用 Handler 进行这些线程之间的通信因为您需要检测何时完成 api 调用并成功获取数据。 或者您可以使用任何第三方AndroidNetworking 库进行线程安全网络调用。

【讨论】：

感谢您的建议。你的意思是我应该使用 AsyncTask 来获取 api 数据？
是的，您也可以使用AsyncTask。但是第三方库对您来说非常容易。

【解决方案4】：

1.改变

CustomAdapter customAdapter = new CustomAdapter(getApplicationContext(), ArrayList NameArrayList, ArrayList IconArrayList);

到这里

CustomAdapter customAdapter = new CustomAdapter(getApplicationContext(),  NameArrayList,  IconArrayList);

2.改变

 @Override
public Object getItem(int i) {
    return null;
}

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

到这里

public Object getItem(int i) {
    return i;
}

public long getItemId(int i) {
    return i;
}

【讨论】：