ListView多条目加载

落日映苍穹つ 2022-06-08 01:19 145阅读 0赞

在现实的项目开发中，listView往往会加载不同类型的数据，这就要求我们要对listView进行多条目的加载，对数据类型进行判断，怎么判断呢？主要在适配器里面进行类型的判断。

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代码如下：在listView适配器重写的四个方法的基础上，再手动重写两个方法，分别是：getViewTypeCount()，getItemViewType(int position)，这两个方法，第一个是确定加载条木有几种数据类型，第二个是对数据进行判断和分类的。

package com.example.wangrx.wangruixin1509c20170909;
    
    import android.app.Activity;
    import android.os.Bundle;
    import android.widget.ListView;
    
    public class MainActivity extends Activity {
    
        String path = "http://v.juhe.cn/toutiao/index?type=top&key=2f092bd9ce76c0257052d6d3c93c11b4";
        private ListView lv;
    
        @Override protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            init();
            initGetData(path);
    
        }
        private void init(){
            lv = findViewById(R.id.lv);
        }
        private void initGetData(String path){
            MyTask myTask = new MyTask(MainActivity.this,path,"GET",lv);
            myTask.execute();
        }
    }

AsyncTask请求：

package com.example.wangrx.wangruixin1509c20170909;
    
    import android.content.Context;
    import android.content.Intent;
    import android.os.AsyncTask;
    import android.view.View;
    import android.widget.AdapterView;
    import android.widget.ListView;
    
    import com.google.gson.Gson;
    
    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.io.UnsupportedEncodingException;
    import java.net.HttpURLConnection;
    import java.net.MalformedURLException;
    import java.net.URL;
    import java.net.URLConnection;
    import java.util.List;
    
    import bean.JavaBean;
    
    /** * Created by Wangrx on 2017/9/8. */ class MyTask extends AsyncTask<String,Integer,String>{
        private String path;
        private Context context;
        private String get;
        private ListView lv;
        private List<JavaBean.ResultBean.DataBean> list;
    
        public MyTask(MainActivity mainActivity, String path, String get, ListView lv) {
            this.context = mainActivity;
            this.path = path;
            this.get = get;
            this.lv = lv;
    
        }
    
        @Override protected String doInBackground(String... strings) {
            try {
                URL url = new URL(path);
                HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                connection.setRequestMethod(get);
                connection.setReadTimeout(5000);
                connection.setConnectTimeout(5000);
                int responseCode = connection.getResponseCode();
                if (responseCode == 200){
                    InputStream inputStream = connection.getInputStream();
                    String s = steamToString(inputStream, "utf-8");
                    return s;
                }
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
    
            return null;
        }
    
        @Override protected void onPostExecute(String s) {
            super.onPostExecute(s);
    
            Gson gson = new Gson();
            JavaBean bean = gson.fromJson(s, JavaBean.class);
            list = bean.getResult().getData();
    
            MyAdapter myAdapter = new MyAdapter(context, list);
            lv.setAdapter(myAdapter);
            lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                    String url = list.get(i).getUrl();
                    Intent intent = new Intent(context, Main2Activity.class);
                    intent.putExtra("url",url);
                    context.startActivity(intent);
                }
            });
    
        }
        private String steamToString(InputStream inputStream,String charset){
            try {
                InputStreamReader inputStreamReader = new InputStreamReader(inputStream, charset);
                BufferedReader reader = new BufferedReader(inputStreamReader);
                String s = null;
                StringBuilder builder = new StringBuilder();
                while ((s=reader.readLine())!=null) {
                    builder.append(s);
                }
    
                reader.close();
                return builder.toString();
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
    
    
            return null;
        }
    }
    设置适配器：

package com.example.wangrx.wangruixin1509c20170909;
    
    import android.content.Context;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.BaseAdapter;
    import android.widget.ImageView;
    import android.widget.TextView;
    
    import com.nostra13.universalimageloader.core.ImageLoader;
    
    import java.util.List;
    
    import bean.JavaBean;
    
    /** * Created by Wangrx on 2017/9/8. */ class MyAdapter extends BaseAdapter{
        private Context context;
        private List<JavaBean.ResultBean.DataBean> list;
        private static final int typeone = 0;
        private static final int typetwo = 1;
        private static final int typethree = 2;
        public MyAdapter(Context context, List<JavaBean.ResultBean.DataBean> list) {
            this.context = context;
            this.list = list;
    
        }
    
        @Override public int getCount() {
            return list.size();
        }
    
        @Override public Object getItem(int i) {
            return list.get(i);
        }
    
        @Override public long getItemId(int i) {
            return i;
        }
    
        @Override public View getView(int i, View view, ViewGroup viewGroup) {
            ViewHolder1 holder1 = null;
            ViewHolder2 holder2 = null;
            ViewHolder3 holder3 = null;
            int type = getItemViewType(i);
            if (view == null){
    
                switch (type){
                    case typeone:
                        holder1 = new ViewHolder1();
                        view = View.inflate(context,R.layout.item1,null);
                        holder1.item1_title = view.findViewById(R.id.item1_title);
                        holder1.item1_img1 = view.findViewById(R.id.item1_img1);
                        holder1.item1_img2 = view.findViewById(R.id.item1_img2);
                        holder1.item1_img3 = view.findViewById(R.id.item1_img3);
                        view.setTag(holder1);
                        break;
                    case typetwo:
                        holder2 = new ViewHolder2();
                        view = View.inflate(context,R.layout.item2,null);
                        holder2.item2_title = view.findViewById(R.id.item2_title);
                        holder2.item2_img1 = view.findViewById(R.id.item2_img1);
                        holder2.item2_img2 = view.findViewById(R.id.item2_img2);
    
                        view.setTag(holder2);
                        break;
                    case typethree:
                        holder3 = new ViewHolder3();
                        view = View.inflate(context,R.layout.item3,null);
                        holder3.item3_title = view.findViewById(R.id.item3_title);
                        holder3.item3_img1 = view.findViewById(R.id.item3_img1);
    
                        view.setTag(holder3);
                        break;
                }
            }else {
                switch (type){
                    case typeone:
                        holder1 = (ViewHolder1) view.getTag();
                        holder1.item1_title.setText(list.get(i).getTitle());
                        ImageLoader.getInstance().displayImage(list.get(i).getThumbnail_pic_s(),holder1.item1_img1);
                        ImageLoader.getInstance().displayImage(list.get(i).getThumbnail_pic_s02(),holder1.item1_img2);
                        ImageLoader.getInstance().displayImage(list.get(i).getThumbnail_pic_s03(),holder1.item1_img3);
                        break;
                    case typetwo:
                        holder2 = (ViewHolder2) view.getTag();
                        holder2.item2_title.setText(list.get(i).getTitle());
                        ImageLoader.getInstance().displayImage(list.get(i).getThumbnail_pic_s(),holder2.item2_img1);
                        ImageLoader.getInstance().displayImage(list.get(i).getThumbnail_pic_s02(),holder2.item2_img2);
                        break;
                    case typethree:
                        holder3 = (ViewHolder3) view.getTag();
                        holder3.item3_title.setText(list.get(i).getTitle());
                        ImageLoader.getInstance().displayImage(list.get(i).getThumbnail_pic_s(),holder3.item3_img1);
    
                        break;
                }
            }
            return view;
        }
    
        @Override public int getItemViewType(int position) {
    
            if (!(list.get(position).getThumbnail_pic_s()==null)){
                if (!(list.get(position).getThumbnail_pic_s02()==null)){
                    if (!(list.get(position).getThumbnail_pic_s03()==null)){
                        return typeone;
                    }else {
                        return typetwo;
                    }
                }else{
                    return typethree;
                }
    
            }else {
                return -1;
            }
    
        }
    
        @Override public int getViewTypeCount() {
            return 3;
        }
        class ViewHolder1{
    
            TextView item1_title;
            ImageView item1_img1;
            ImageView item1_img2;
            ImageView item1_img3;
        }
        class ViewHolder2{
            TextView item2_title;
            ImageView item2_img1;
            ImageView item2_img2;
    
        }
        class ViewHolder3{
            TextView item3_title;
            ImageView item3_img1;
        }
    }
    第二个页面 WebView：

package com.example.wangrx.wangruixin1509c20170909;
    
    import android.app.Activity;
    import android.content.Intent;
    import android.os.Bundle;
    import android.webkit.WebSettings;
    import android.webkit.WebView;
    import android.webkit.WebViewClient;
    
    public class Main2Activity extends Activity {
    
        @Override protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main2);
            Intent intent = getIntent();
            String url = intent.getStringExtra("url");
            WebView web = findViewById(R.id.web);
            web.loadUrl(url);
            web.setWebViewClient(new WebViewClient());
    
            WebSettings settings = web.getSettings();
            settings.setJavaScriptCanOpenWindowsAutomatically(true);
            settings.setJavaScriptEnabled(true);
    
    
        }
    }

图片加载：

package util;
    
    import android.app.Application;
    
    import com.example.wangrx.wangruixin1509c20170909.R;
    import com.nostra13.universalimageloader.core.DisplayImageOptions;
    import com.nostra13.universalimageloader.core.ImageLoader;
    import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;
    import com.nostra13.universalimageloader.core.display.FadeInBitmapDisplayer;
    
    /** * Created by Wangrx on 2017/9/8. */ public class MyApplication extends Application{
        @Override public void onCreate() {
    
            super.onCreate();
            DisplayImageOptions options = new DisplayImageOptions.Builder()
                    .showImageOnLoading(R.mipmap.ic_launcher)
                    .displayer(new FadeInBitmapDisplayer(2000)).cacheOnDisc(true)
                    .cacheInMemory(true).build();
    
            ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(
                    this).defaultDisplayImageOptions(options).threadPoolSize(5)
                    .build();
    
            ImageLoader.getInstance().init(config);
    
        }
    
    }

布局文件：

main1：

<?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context="com.example.wangrx.wangruixin1509c20170909.MainActivity">
    
        <ListView android:id="@+id/lv"
            android:layout_width="match_parent"
            android:layout_height="match_parent"></ListView>
    
    </RelativeLayout>
     main2：

<?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context="com.example.wangrx.wangruixin1509c20170909.Main2Activity">
    
        <WebView android:id="@+id/web"
            android:layout_width="match_parent"
            android:layout_height="match_parent"></WebView>
    </RelativeLayout>

item1：

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical" android:layout_width="match_parent"
        android:layout_height="match_parent">
    
        <TextView android:id="@+id/item1_title"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:textSize="25sp"
            />
        <LinearLayout android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="horizontal">
    
            <ImageView android:id="@+id/item1_img1"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1" />
    
            <ImageView android:id="@+id/item1_img2"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1" />
    
            <ImageView android:id="@+id/item1_img3"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1" />
    
    
        </LinearLayout>
    
    
    </LinearLayout>item2：

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical" android:layout_width="match_parent"
        android:layout_height="match_parent">
    
        <TextView android:id="@+id/item2_title"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:textSize="25sp"
            />
        <LinearLayout android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="horizontal">
    
            <ImageView android:id="@+id/item2_img1"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1" />
    
            <ImageView android:id="@+id/item2_img2"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1" />
    
    
        </LinearLayout>
    
    
    
    
    </LinearLayout>item3：

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
    
        <TextView android:id="@+id/item3_title"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:textSize="25sp" />
    
    
        <ImageView android:id="@+id/item3_img1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
             />
    
    
    </LinearLayout>

[Center]: /images/20220608/e642bdd890bc457cb37e6d2dd50db490.png