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很多时候我们都用得到异步实时加载图片，方式很多，以下是方法之一，实现较为简单；

话不多说直接上代码


getImageWithUrlAsyncTask.class

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.util.Log;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class getImageWithUrlAsyncTask extends AsyncTask<String, Integer, Bitmap> {
    String Url;
    int viewId = 0;
    Bitmap bmp = null;

    public getImageWithUrlAsyncTask(String Url, int viewId,getImageWithUrlAsyncTask.OnPostExecute onPostExecute) {
        this.onPostExecute = onPostExecute;
        this.Url = Url;
        this.viewId = viewId;
    }

    @Override
    protected Bitmap doInBackground(String... strings) {
        try {
            URL myurl = new URL(Url);
            Log.i("getURLimageAsyncTask", "URL: " + Url);
            // 获得连接
            HttpURLConnection conn = (HttpURLConnection) myurl.openConnection();
            conn.setConnectTimeout(60*1000);//设置超时
            conn.setDoInput(true);
            conn.setUseCaches(false);//不缓存
            conn.connect();
            InputStream is = conn.getInputStream();//获得图片的数据流
            if (position == -1) {
                bmp = BitmapFactory.decodeStream(is);
            } else {
                BitmapFactory.Options options = new BitmapFactory.Options();
                options.inPreferredConfig = Bitmap.Config.RGB_565;
                options.inSampleSize = 20;
                bmp = BitmapFactory.decodeStream(is, null, options);

            }
            is.close();
            return bmp;
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }

    @Override
    protected void onPostExecute(Bitmap bitmap) {
        super.onPostExecute(bitmap);
        onPostExecute.onPostExecute(viewId, bitmap);
    }

    OnPostExecute onPostExecute;

    public interface OnPostExecute {
        void onPostExecute(int viewId, Bitmap bitmap);
    }

//    在得到InputStream之后，先将InputStream转化为字节数组，然后在使用decodeByteArray方法解析图片，先将InputStream流转为byte数组

    private byte[] inputStream2ByteArr(InputStream inputStream) throws IOException {
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        byte[] buff = new byte[1024];
        int len = 0;
        while ((len = inputStream.read(buff)) != -1) {
            outputStream.write(buff, 0, len);
        }
        inputStream.close();
        outputStream.close();
        return outputStream.toByteArray();
    }

    //    然后在调用如下代码实现解析图片的操作
    private Bitmap decodeBitmap(InputStream is) throws IOException {
        if (is == null) {
            return null;
        }
        BitmapFactory.Options options = new BitmapFactory.Options();
        //设置该属性可以不占用内存，并且能够得到bitmap的宽高等属性，此时得到的bitmap是空
        options.inJustDecodeBounds = true;
        byte[] data = inputStream2ByteArr(is);//将InputStream转为byte数组，可以多次读取
        Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length, options);
        //设置计算得到的压缩比例
//        options.inSampleSize = 1;
        //设置为false，确保可以得到bitmap != null
        options.inJustDecodeBounds = false;
        bitmap = BitmapFactory.decodeByteArray(data, 0, data.length, options);
        return bitmap;
    }
}

在需要的地方调用即可

 new getImageWithUrlAsyncTask( url, viewId, new getImageWithUrlAsyncTask.OnPostExecute() {
                                @Override
                                public void onPostExecute(int viewId, Bitmap bitmap) {
                                   
                                }
                            }).execute();