android 多线程 AsyncTask 下载图片

AsyncTask 下载图片

package com.test.network;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ImageView;

import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.Objects;

/**
 * AsyncTask 实现图片下载、显示
 */
public class AsyncDownLoadActivity extends AppCompatActivity {

    private String urlPath = "http://img4.imgtn.bdimg.com/it/u=3340865222,3464212128&fm=21&gp=0.jpg";
    private ImageView imageView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_async_down_load);
        imageView = (ImageView) findViewById(R.id.imageView);
        new AsynPicTask().execute(imageView, urlPath);
    }

    class AsynPicTask extends AsyncTask<Object, Object, Bitmap> {

        private ImageView imageView;

        protected void onPreExecute() {
        }

        //执行耗时操作
        @Override
        protected Bitmap doInBackground(Object... params) {
            imageView = (ImageView) params[0];
            Bitmap bitmap = null;
            try {
                URL url = new URL((String) params[1]);
                URLConnection urlConnection = url.openConnection();
                urlConnection.setConnectTimeout(3000);
                urlConnection.connect();

                InputStream inputStream = urlConnection.getInputStream();

                bitmap = BitmapFactory.decodeStream(inputStream);
                inputStream.close();

            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return bitmap;
        }

        protected void onProgressUpdate(Object... values) {
        }

        //耗时操作返回结果
        protected void onPostExecute(Bitmap result) {
            imageView.setImageBitmap(result);
        }

    }
}