直接看代码：MainActivity：

package com.example.textwsjdemo;

import com.nostra13.universalimageloader.cache.disc.naming.Md5FileNameGenerator;

import com.nostra13.universalimageloader.core.DisplayImageOptions;

import com.nostra13.universalimageloader.core.ImageLoader;

import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;

import com.nostra13.universalimageloader.core.assist.QueueProcessingType;

import com.nostra13.universalimageloader.core.display.RoundedBitmapDisplayer;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.ImageView;

public class MainActivity extends Activity {

    private String url;

	private Button bt_hehe;

	private ImageView iv_photo;

	private DisplayImageOptions defaultOptions;

	private ImageLoaderConfiguration config;

	@Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        initView();

        defaultOptions = new DisplayImageOptions.Builder()

        .showStubImage(R.drawable.ic_launcher)         //载入開始默认的图片

        .showImageForEmptyUri(R.drawable.ic_launcher)     //url爲空會显示该图片。自己放在drawable里面的

        .showImageOnFail(R.drawable.ic_launcher)    //载入图片出现故障，会显示该图片

        .cacheInMemory(true)     //缓存用  fslae 不缓存

        .cacheOnDisc(true)      //缓存用

        .displayer(new RoundedBitmapDisplayer(5))  //图片圆角显示。值为整数

        .build();

        config = new ImageLoaderConfiguration.Builder(MainActivity.this)

        .defaultDisplayImageOptions(defaultOptions)

        .threadPriority(Thread.NORM_PRIORITY - 2)

        .denyCacheImageMultipleSizesInMemory()

        .discCacheFileNameGenerator(new Md5FileNameGenerator())

        .tasksProcessingOrder(QueueProcessingType.LIFO)

//        .enableLogging() // Not necessary in common

        .build();

        ImageLoader.getInstance().init(config);

    }

	private void initView() {

		//图片URL

		url = "http://file.koolearn.com/20131018/1382077932449.jpg";

		bt_hehe = (Button) findViewById(R.id.bt_hehe);

		iv_photo = (ImageView) findViewById(R.id.iv_photo);

		bt_hehe.setOnClickListener(new OnClickListener() {

			@Override

			public void onClick(View v) {

				// TODO Auto-generated method stub

				ImageLoader.getInstance().displayImage(url,iv_photo, defaultOptions); //url为图片地址，iv_photo 为ImageView布局，

			}

		});

	}

}

就这点代码就能够实现载入网络图片，导入Image-Loader 的jar包就可以

Image-Loader下载：  https://github.com/nostra13/Android-Universal-Image-Loader