网络请求数据+viewpager+fragment

最新推荐文章于 2021-05-27 02:58:07 发布

jiaxiaofei622

最新推荐文章于 2021-05-27 02:58:07 发布

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文章标签：网络请求数据+viewpager+fragment

本文链接：https://blog.youkuaiyun.com/jiaxiaofei622/article/details/84726692

本文详细介绍了在MainActivity中如何结合ViewPager与多个Fragment，每个Fragment分别进行网络请求获取数据。通过优化的NewsAdapter和UserAdapter实现数据展示，同时讲解了App中设置图片的类及其在网络请求数据流程中的应用。

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Mainactivity.class

	package com.example.lx_zk1.activity;
	
	import android.support.design.widget.TabLayout;
	import android.support.v4.view.ViewPager;
	import android.support.v7.app.AppCompatActivity;
	import android.os.Bundle;
	
	import com.example.lx_zk1.R;
	import com.example.lx_zk1.adapter.TabAdapter;
	
	public class MainActivity extends AppCompatActivity {

    private ViewPager viewPager;
    private TabLayout tabLayout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //获取资源ID
        viewPager = findViewById(R.id.viewpager);
        tabLayout = findViewById(R.id.tab);

        //设置适配器
        TabAdapter adapter = new TabAdapter(getSupportFragmentManager());
        viewPager.setAdapter(adapter);
        //根据viewpager设置tab
        tabLayout.setupWithViewPager(viewPager);
	    }
	}

NewsAdapter`

package com.example.lx_zk1.adapter;

import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;

import com.example.lx_zk1.fragment.SFragment;
import com.example.lx_zk1.fragment.WFragment;

public class TabAdapter extends FragmentPagerAdapter {
    //创建一个string集合
    private String[] menus = new String[]{
        "首页","视频","我的"
    };

    public TabAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int position) {
        switch (position){
            case 0:
                return new SFragment();
                default:
                    return new WFragment();
        }
    }

    @Nullable
    @Override
    public CharSequence getPageTitle(int position) {
        return menus[position];
    }

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

优化代码UserAdapter

package com.example.lx_zk1.adapter;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import com.example.lx_zk1.R;
import com.example.lx_zk1.bean.Bean;
import com.nostra13.universalimageloader.core.ImageLoader;

import java.util.ArrayList;
import java.util.List;

public class UserAdapter extends BaseAdapter {
    private List<Bean.DataBean> list;
    private Context context;

    public UserAdapter(Context context) {
        this.context = context;
        list = new ArrayList<>();
    }

    public void setList(List<Bean.DataBean> list) {
        this.list = list;
        notifyDataSetChanged();
    }

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

    @Override
    public Bean.DataBean getItem(int position) {
        return list.get(position);
    }

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if (convertView == null){
            convertView = LayoutInflater.from(context).inflate(R.layout.item,parent,false);
            holder = new ViewHolder();
            holder.imageView = convertView.findViewById(R.id.imageview);
            holder.textView = convertView.findViewById(R.id.textview);
            convertView.setTag(holder);
        }else {
            holder = (ViewHolder) convertView.getTag();
        }
        holder.textView.setText(getItem(position).getNews_title());
        ImageLoader.getInstance().displayImage(getItem(position).getPic_url(),holder.imageView);

        return convertView;
    }

    class ViewHolder{
        private TextView textView;
        private ImageView imageView;
    }
}

一个Fragment网络请求数据

在这里插入代码片package com.example.lx_zk1.fragment;

import android.annotation.SuppressLint;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;

import com.example.lx_zk1.R;
import com.example.lx_zk1.adapter.UserAdapter;
import com.example.lx_zk1.bean.Bean;
import com.google.gson.Gson;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.List;

public class SFragment extends Fragment {
    private ListView listView;
    private UserAdapter adapter;
    private List<Bean.DataBean> list;
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.sfragment,container,false);

        return view;
    }

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        //获取资源id
        listView = view.findViewById(R.id.listview);
        //设置适配器
        adapter = new UserAdapter(getActivity());
        listView.setAdapter(adapter);

        initData();
    }

    private String urlstr = "http://api.expoon.com/AppNews/getNewsList/type/1/p/1";

    private void initData(){
        @SuppressLint("StaticFieldLeak") AsyncTask<String, Void, List<Bean.DataBean>> task = new AsyncTask<String, Void, List<Bean.DataBean>>() {
            @Override
            protected List<Bean.DataBean> doInBackground(String... strings) {
                try {
                    URL url = new URL(urlstr);
                    HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
                    urlConnection.setConnectTimeout(5000);
                    urlConnection.setReadTimeout(5000);
                    int responseCode = urlConnection.getResponseCode();
                    if (responseCode==200){
                        String result = stream2String(urlConnection.getInputStream());
                        Gson gson = new Gson();
                        Bean bean = gson.fromJson(result, Bean.class);

                        return bean.getData();
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }


                return null;
            }

            @Override
            protected void onPostExecute(List<Bean.DataBean> lists) {
                super.onPostExecute(lists);
                list = lists;
                adapter.setList(lists);
            }
        }.execute(urlstr);
    }

    private String stream2String(InputStream inputStream) throws IOException {
        StringBuilder stringBuilder = new StringBuilder();
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
        for (String tmp = bufferedReader.readLine(); tmp != null; tmp = bufferedReader.readLine()){
            stringBuilder.append(tmp);
        }

        return stringBuilder.toString();
    }

}

另一个请求数据

在这里插入代码片package com.example.lx_zk1.fragment;

import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.example.lx_zk1.R;

public class WFragment extends Fragment {
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.wfragment,container,false);

        return view;
    }
}

一个App设置图片的类

在这里插入代码片package com.example.lx_zk1.util;

import android.app.Application;
import android.graphics.Bitmap;

import com.example.lx_zk1.R;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;

public class App extends Application {
    @Override
    public void onCreate() {
        super.onCreate();

        ImageLoaderConfiguration configuration = new ImageLoaderConfiguration.Builder(this)
                .memoryCacheSize(10)
                .diskCacheSize(10*1024*1024)
                .defaultDisplayImageOptions(new DisplayImageOptions.Builder()
                        .bitmapConfig(Bitmap.Config.RGB_565)
                        .showImageOnLoading(R.mipmap.ic_launcher)
                        .showImageOnFail(R.mipmap.ic_launcher)
                        .showImageForEmptyUri(R.mipmap.ic_launcher)
                        .cacheOnDisk(true)
                        .cacheInMemory(true)
                        .build()
                ).build();
        ImageLoader.getInstance().init(configuration);

    }
}