fragment中的ImagView+Text多条目，点击ImageView二次采样切换相册图片

##Fragmentd的 XML：

<?xml version="1.0" encoding="utf-8"?>

<android.support.constraint.ConstraintLayout
xmlns:android=“http://schemas.android.com/apk/res/android” android:layout_width=“match_parent”
android:layout_height=“match_parent”>

</android.support.constraint.ConstraintLayout>

二次采样写入到工具类中：

package com.example.work09_07;

import android.content.Context;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.AsyncTask;
import android.provider.MediaStore;
import android.support.v4.content.CursorLoader;

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.URL;

public class NetUntil {
private static NetUntil instance;
private NetUntil(){

}
public static NetUntil getInstance(){
    if (instance==null){
        instance=new NetUntil();
    }
    return instance;
}

//1.根据相册路径得到真实路径
public String geturi(Context con,Uri uri){
    String[] strings={MediaStore.Images.Media.DATA};
    CursorLoader loader = new CursorLoader(con, uri, strings, null, null, null);
    Cursor cursor = loader.loadInBackground();
    int indexOrThrow = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
    cursor.moveToFirst();
    return cursor.getString(indexOrThrow);
}

//2.根据真实路径进行二次采样
public Bitmap getBit(Context con,Uri uri,int weidth,int height){
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds=true;
    String geturi = geturi(con, uri);
    BitmapFactory.decodeFile(geturi,options);
    int outWidth = options.outWidth;
    int outHeight = options.outHeight;
    options.inSampleSize=Math.max(outWidth/weidth,outHeight/height);
    options.inJustDecodeBounds=false;
    Bitmap bitmap = BitmapFactory.decodeFile(geturi, options);
    return bitmap;
}


public interface Callback<T> {
    void onSuccess(T t);
}

//异步任务
public void getRequest(String lujing, final Class clazz, final Callback callBack) {
    new AsyncTask<String, Void, Object>() {
        @Override
        protected Object doInBackground(String... strings) {
            return getRequest(strings[0], clazz);
        }

        @Override
        protected void onPostExecute(Object o) {
            callBack.onSuccess(o);
        }
    }.execute(lujing);
}

//网络解析
public <T> T getRequest(String urlPath, Class clazz) {
    T t = (T) new Gson().fromJson(getRequest(urlPath), clazz);
    return t;
}

//网络请求
public String getRequest(String urlPath) {
    String result = "";
    try {
        //定义地址
        URL url = new URL(urlPath);
        //打开连接
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
        //请求方法
        urlConnection.setRequestMethod("GET");
        //读取超时
        urlConnection.setReadTimeout(5000);
        //连接超时
        urlConnection.setConnectTimeout(5000);
        if (urlConnection.getResponseCode() == 200) {
            result = stream2String(urlConnection.getInputStream());
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    //return null;
    return result;
}

//字节流转换为字符流
private String stream2String(InputStream inputStream) throws IOException {
    InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
    BufferedReader buff = new BufferedReader(inputStreamReader);
    StringBuilder builder = new StringBuilder();
    for (String tmp = buff.readLine(); tmp != null; tmp = buff.readLine()) {
        builder.append(tmp);
    }
    return builder.toString();
}

}

Fragment:

package com.example.work09_07;

import android.content.Intent;
import android.graphics.Bitmap;
import android.net.Uri;
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.AdapterView;
import android.widget.ListView;

import com.example.work09_07.Adapter.Left_Adapter;

public class LeftFragment extends Fragment {
//获取资源ID
private ListView listView;
private Left_Adapter adapter;
private Uri uri;//从相册中得到图片的路径
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
//有图片和条目
View view=inflater.inflate(R.layout.leftfragment,container,false);
return view;
}

@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    listView=view.findViewById(R.id.left_listview);


//条目点击，viewpager跳转到互动的fragment
    //通过Activity联系
    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView <?> parent, View view, int position, long id) {
            if (position == 0) {
                //对图片进行切换
                //1.从相册获取图片
                Intent it = new Intent(Intent.ACTION_PICK);
                it.setType("image/*");
                startActivityForResult(it,100);

            }
            // else {                                           //position为侧拉的            
         //    ((MainActivity) getActivity()).getData(position - 1);
        //    }
        }
    });

    //适配器
    adapter=new Left_Adapter(getActivity());
    listView.setAdapter(adapter);

}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

// Toast.makeText(getActivity(),“12”,Toast.LENGTH_LONG).show();
if (requestCode100&&resultCodegetActivity().RESULT_OK){

        Uri uri = data.getData();
        //2.二次采样
        Bitmap bit = NetUntil.getInstance().getBit(getActivity(), uri, 100, 100);
        adapter.getImage(bit);
        return;
    }
}

}

Fragment的适配器：

package com.example.work09_07.Adapter;

import android.content.Context;
import android.graphics.Bitmap;
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.work09_07.R;

public class Left_Adapter extends BaseAdapter {
private Context con;
private String[] menus=new String[]{“我的”,“视频”,“游戏”};
private Bitmap bit;
public Left_Adapter(Context con) {
this.con = con;
}
//多条目

@Override
public int getViewTypeCount() {
    return 2;
}

@Override
public int getItemViewType(int position) {
    return position==0?0:1;
}
//传递参数
public void getImage(Bitmap bit){
    this.bit=bit;
    notifyDataSetChanged();
}
@Override
public int getCount() {
    return menus.length+1;
}

@Override
public String getItem(int position) {
    if (position==0){
        return null;
    }
    return menus[position-1];
}

@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(con)
      .inflate(getItemViewType(position)==0? R.layout.has_image:R.layout.no_image,parent,false);
        holder=new ViewHolder();
        holder.textView=convertView.findViewById(R.id.no_textview);
        holder.imageView=convertView.findViewById(R.id.has_image);
        convertView.setTag(holder);
    }else {
        holder= (ViewHolder) convertView.getTag();
    }
    //记住！！！！！！！！要判断
    if (getItemViewType(position)==1){
        holder.textView.setText(getItem(position));
    }else if (getItemViewType(position)==0){
        if (bit!=null){
        holder.imageView.setImageBitmap(bit);
        }
    }

    return convertView;
}

class ViewHolder{
    ImageView imageView;
    TextView textView;
}

}