Async load image from internet to ListView

Android example to load images in AsyncTask from internet to ListView.


MainActivity.java

package com.example.androidasynclist;

import java.io.IOException;
import java.io.InputStream;
import java.lang.ref.WeakReference;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.Arrays;

import android.support.v7.app.ActionBarActivity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {

 final static String src[] = {
   "https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhebk5mCDa6BdlhTDnRYqjBu2QxgPh1_BhUjbeDZ1Za_cvFjxmfcRwNsJLwpmCcDsan5lBPeli4gGl-uB_iNunzkZbSPMq_ZAgod-BUEuCuJI08ZDt3jU2PCrnHaBGV3ICxL0OJyTkCW-Q/s1600/_01.png",
   "https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgGdysJIrMiyDZr-nSkop_TyQFGxAQ2XrQt0wx0JlM2mQzL1jRZefHRfo4rlH5gv7rd0bx5U1lThuAvpD1Xp9ErrPzs94ujFAf6Vo5slnWimMfJcZQAGYR5a2HzwUOmTcP4emHif_OoBQk/s1600/_02.png",
   "https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhERNjOKlB3htQ-Wl6F7FrwvqlhXVpoMRSHhzgXm58_eM3XSvFn71mg4t4xjK9iFo2K0yj1LrRCiG8Cl9TrvZPlijvLavgOU35YcFltTdOgCPf6Awfiji64o16UkRH-aQTcgXSBvn7pwcc/s1600/_03.png",
   "https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkUbbj-FFtPPHzfwVZ3Q42mgFnUrKtOcH_C3KpvYycZ7pmKqkTRhK6GgMqJVrFDt3vq_gACET0dtXEEnGsKCFOUS9GOjD0NqGTvqm0hGQMzHfNY7nSrpa5ybELGcuHd6CsqQytkExGgC0/s1600/_04.png",
   "https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEggEu8yczAgd-adPQTOfiefEy6QkwwHGQZCVJPszbBc5dlXN5p-S15yV69rhhH8759T8P9R7IU6SpIRD5k4qUFTpZG6N2tI-2awRhbXnu9n1bpElXCPRJMApQrHg5r4f2wC1bCUIPitc9g/s1600/_05.png",
   "https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEies8eXNYKRz5lYLsFfiorfjp5d5sS_WCUi34xN6X4_MqhA8bkmxwF4okYIwIQuDWeVs9pQbGsTzC7KiS0hHzDonRwrBt0oTd9S4NETXijXWtkAx0EgFnJakH8FqPZVD6vFJRkgif-pcPo/s1600/_06.png",
   "https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhtoO8ZkLctGfecOcjbuc_kKIV2rcdufm-jAy1UQEsOMW3_xqo-FjIBKXmGU-cTK0sMZE1yZ1X6Z9bUwJTh93BPJZmcl34K-m4CSpIfngDifffQxgZnTU7nyehOdNcDHNgnPJWqRP4F6LA/s1600/_07.png",
   "https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwiWd4s1OIxvwXrqwW_LuvBszdKHHyNAAvGybe9QnaxbRCem6fNQOGn93s8vGLvFgiMXYcnqSzUlJVNHAn0uTT-DaaaUXsEeo9_AiaJpppguDLk4lQmaNAB_-_p38cL_m_I0-5rIc_ju0/s1600/_08.png",
   "https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmwWjqsY5JvFzLbAQfywTip6IiLfVngF23oQaHHBXdzUmB7jm16-RaQAjNUrgE0_kiVJCs859ZSwzSOWIoDgglo16vitk0RWFVxLRQ87djmd-vsyJQ2QHM9KLNQfXtt0yQsIFvOwGMj8w/s1600/_09.png",
   "https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjPTaErrUOaeuseHt3T7ychIazcsesUX_i0tRdPWWoE8tktVvCFzSHLmsAyEjiqniV8mmbn_lW3lDc105Ds-fcCQBf9MH_nGpto81Xx0bHei7GaXRBW_N7MviLJj3TclKN3T8mPD0SDPrg/s1600/_10.png",
   "https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhuLNKdjiwzMTZxQItfeK3Py3n-ZFVaJskcjlVIpDx4C0ba02cTbgpcsnaw_BwZ61VUQZaiwh9cHbq9QEMCKLERbDYLR6ZiXMFXi0PByUXCuNKV6qoqLwv1bjpafdvikTi26OZd9VWjDUs/s1600/_11.png",
   "https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgOLVzuJUD5aEclSKsDvAty6wyccSbSjJa1SPjb-nA43e_QOb2Drwk4dFNLZj_licIxuXnw9VruO-1drxwK6oZOg5mE97ZpNIAmArrY485A3NEka6zJiIlAPhpkV2vAxu8YzQ2ZI42gBnE/s1600/_12.png" };

 ListView imageList;

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

  imageList = (ListView) findViewById(R.id.imagelist);
  ArrayList srcList = new ArrayList(Arrays.asList(src));
  imageList.setAdapter(new CustomListAdapter(this, srcList));
 }

 // ----------------------------------------------------

 public class CustomListAdapter extends BaseAdapter {
  private ArrayList listData;
  private LayoutInflater layoutInflater;

  public CustomListAdapter(Context context, ArrayList listData) {
   this.listData = listData;
   layoutInflater = LayoutInflater.from(context);
  }

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

  @Override
  public Object getItem(int position) {
   return listData.get(position);
  }

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

  public View getView(int position, View convertView, ViewGroup parent) {
   ViewHolder holder;
   if (convertView == null) {
    convertView = layoutInflater.inflate(R.layout.row, null);
    holder = new ViewHolder();
    holder.icon = (ImageView)convertView.findViewById(R.id.icon);
    holder.text = (TextView)convertView.findViewById(R.id.text);
    convertView.setTag(holder);
   } else {
    holder = (ViewHolder) convertView.getTag();
   }
   
   holder.text.setText(String.valueOf(position));

   if (holder.icon != null) {
    new BitmapWorkerTask(holder.icon).execute(listData.get(position));
   }
   return convertView;
  }

  class ViewHolder {
   ImageView icon;
   TextView text;
  }
 }

 // ----------------------------------------------------
 // Load bitmap in AsyncTask
 // ref:
 // http://developer.android.com/training/displaying-bitmaps/process-bitmap.html
 class BitmapWorkerTask extends AsyncTask {
  private final WeakReference imageViewReference;
  private String imageUrl;

  public BitmapWorkerTask(ImageView imageView) {
   // Use a WeakReference to ensure the ImageView can be garbage
   // collected
   imageViewReference = new WeakReference(imageView);
  }

  // Decode image in background.
  @Override
  protected Bitmap doInBackground(String... params) {
   imageUrl = params[0];
   return LoadImage(imageUrl);
  }

  // Once complete, see if ImageView is still around and set bitmap.
  @Override
  protected void onPostExecute(Bitmap bitmap) {
   if (imageViewReference != null && bitmap != null) {
    final ImageView imageView = imageViewReference.get();
    if (imageView != null) {
     imageView.setImageBitmap(bitmap);
    }
   }
  }

  private Bitmap LoadImage(String URL) {
   Bitmap bitmap = null;
   InputStream in = null;
   try {
    in = OpenHttpConnection(URL);
    bitmap = BitmapFactory.decodeStream(in);
    in.close();
   } catch (IOException e1) {
   }
   return bitmap;
  }

  private InputStream OpenHttpConnection(String strURL)
    throws IOException {
   InputStream inputStream = null;
   URL url = new URL(strURL);
   URLConnection conn = url.openConnection();

   try {
    HttpURLConnection httpConn = (HttpURLConnection) conn;
    httpConn.setRequestMethod("GET");
    httpConn.connect();

    if (httpConn.getResponseCode() == HttpURLConnection.HTTP_OK) {
     inputStream = httpConn.getInputStream();
    }
   } catch (Exception ex) {
   }
   return inputStream;
  }
 }
}

/res/layout/activity_main.xml

    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.androidasynclist.MainActivity" >

            android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://picturedmagazine.blogspot.com/"
        android:textStyle="bold" />

            android:id="@+id/imagelist"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" />

/res/layout/row.xml

    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >

            android:id="@+id/icon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

            android:id="@+id/text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

Permission of "android.permission.INTERNET" is needed in AndroidManifest.xml.

Download the files.

Related:
- Load WebP from Internet and display in ListView