下载网路图片到SD卡上新建文件夹当中

1.DownloadImages.java文件

package cn.com;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.protocol.HTTP;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Environment;

public class DownloadImages extends Activity {
        //这下面3个参数用于网络连接服务器端,获取图片流数据
	private final static String HOST = "127.0.0.1";
	private final static int PORT = 8080;
	private final static String HOST_IP = "http://" + HOST + ":" + PORT;
	// 图片接口路径
	private static String imageURL = HOST_IP+"************";
	private int bitmapIndex = 0;
	private File dFile1;
	private static Bitmap[] bitmapFactory = new Bitmap[6];
	private FileOutputStream outs1;
	private int index = 84;
	private String fileDirectory = "";

	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		getSdCardPath();
                imageGet();
	}
        //创建一个SD卡上的文件夹
	public void getSdCardPath() {
		File sdcardDir = Environment.getExternalStorageDirectory();
		String path = sdcardDir.getParent() + sdcardDir.getName();
		fileDirectory = path + java.io.File.separator + "Demo";
		createFile();
	}
	
	public void createFile() {
		try {
			// 1.判断是否存在sdcard
			if (Environment.MEDIA_MOUNTED.equals(Environment
					.getExternalStorageState())) {
				//目录
				System.out.println("_______create Directory________");
	             File path = new File(fileDirectory);
				if (!path.exists()) {
					// 2.创建目录，可以在应用启动的时候创建
					path.mkdirs();
				}
				//文件
				/*File f = new File(fileDirectory + "/notes.txt");
				if (!f.exists()) {
					// 3.创建文件
					f.createNewFile();
				}*/
			    
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
        //可以通过自己构建服务器端文件,传递一定参数进行图片流下载
	public void imageGet() {
		try {
			DefaultHttpClient httpclient = new DefaultHttpClient();
			HttpResponse response;
			HttpPost httpost = new HttpPost(imageURL);
			List<NameValuePair> nvps = new ArrayList<NameValuePair>();
			nvps.add(new BasicNameValuePair("type", "image"));
			nvps.add(new BasicNameValuePair("id", String.valueOf(19)));
			nvps.add(new BasicNameValuePair("fileId", String
					.valueOf(bitmapIndex + 1)));
			httpost.setEntity(new UrlEncodedFormEntity(nvps, HTTP.UTF_8));
			// This is always a final response
			response = httpclient.execute(httpost);
			HttpEntity entity = response.getEntity();
			InputStream is = entity.getContent();
			System.out.println("______"
					+ Environment.getExternalStorageDirectory());
			dFile1 = new File(fileDirectory, (index++) + ".jpg");
			outs1 = new FileOutputStream(dFile1);
			byte buf[] = new byte[1024];
			int numread = 0;
			do {
				// Start reading data from the URL stream
				numread = is.read(buf);
				if (numread < 0) {
					System.out.println("the end !!!!");
					break;
				}
				outs1.write(buf, 0, numread);

			} while (true);
                        //保存在一个位图数组当中,方面后续使用
			bitmapFactory[bitmapIndex++] = BitmapFactory.decodeFile(dFile1
					.getPath());

			if (bitmapIndex == 6) {
				System.out.println("_________download over__________");
				is.close();
				outs1.close();
			} else {
				imageGet();
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

2.当然在配置文件当中,我们需要添加如下:

<!-- 访问网路权限-->
<uses-permission android:name="android.permission.INTERNET" />
<!-- 读写SD卡权限-->
	<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
	<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />