android初级之Android之从网络上获取数据（图片，网页，xml,json等）
1>从网络上获取数据（图片，网页，xml,json等）
A.从网络上获取一张图片，然后显示到手机上
这是在java中
public class ImageRequest {
/**
* @param args
*/
public static void main(String[] args) throws Exception {
URL url = new URL("/2012/0419/20120419023209724.jpg");
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
conn.setRequestMethod("GET");
conn.setConnectTimeout(5 * 1000);
InputStream inStream = conn.getInputStream();//通过输入流获取图片数据
byte[] data = readInputStream(inStream);//得到图片的二进制数据
File imageFile = new File("itcast.jpg");//保存在项目下
FileOutputStream outStream = new FileOutputStream(imageFile);
outStream.write(data);
outStream.close();
}
public static byte[] readInputStream(InputStream inStream) throws Exception{
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];//定义一个1k的缓冲区
int len = 0;
while( (len=inStream.read(buffer)) != -1 ){//返回的是实际的字节数
outStream.write(buffer, 0, len);//将缓冲区的数据写入到内存中
}
inStream.close();
return outStream.toByteArray();
}
}
在手机上
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String path = pathText.getText().toString();
try {
byte[] data = ImageService.getImage(path);
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);//生成位图
imageView.setImageBitmap(bitmap);//显示图片
} catch (Exception e) {
Toast.makeText(ImageShowActivity.this, R.string.error, 1).show();
Log.e(TAG, e.toString());
}
}});
<!-- 访问网络的权限 -->
<uses-permission android:name="android.permission.INTERNET"/>
public class StreamTool {
/**
* 从输入流中获取数据
* @param inStream 输入流
* @return
* @throws Exception
*/
public static byte[] readInputStream(InputStream inStream) throws Exception{
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len = 0;
while( (len=inStream.read(buffer)) != -1 ){
outStream.write(buffer, 0, len);
}
inStream.close();
return outStream.toByteArray();
}
}
-----------------------------------------------------------------------------------------------------
public class ImageService {
public static byte[] getImage(String path) throws Exception {
URL url = new URL("/2012/0419/20120419023209724.jpg");
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
conn.setRequestMethod("GET");
conn.setConnectTimeout(5 * 1000);
InputStream inStream = conn.getInputStream();//通过输入流获取图片数据
return StreamTool.readInputStream(inStream);//得到图片的二进制数据
}
}
B.从网络上获取网页(用的比较少)
byte[] data = readInputStream(inStream);//得到网页的二进制数据
String html = new String(data,"gb2312");
C.从网络上获取xml数据，然后显示在手机上
android手机模拟器本身绑定在模拟器上，所以访问web service的时候不能用local host
或者用127.0.0.1。而应该使用局域网上的ip地址。
public class VideoService {
/**
* 获取最新的视频资讯
* @return
* @throws Exception
*/
public static List<Video> getLastVideos() throws Exception{
String path = "http://192.168.1.100:8080/videoweb/video/list.do";
URL url = new URL(path);
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
conn.setReadTimeout(5*1000);
conn.setRequestMethod("GET");
InputStream inStream = conn.getInputStream();
return parseXML(inStream);
}
/**
* 解析服务器返回的协议，得到视频资讯
* @param inStream
* @return
* @throws Exception
*/
private static List<Video> parseXML(InputStream inStream) throws Exception{
List<Video> videos = null;
Video video = null;
XmlPullParser parser = Xml.newPullParser();
parser.setInput(inStream, "UTF-8");
int eventType = parser.getEventType();//产生第一个事件
while(eventType!=XmlPullParser.END_DOCUMENT){//只要不是文档结束事件
switch (eventType) {
case XmlPullParser.START_DOCUMENT:
videos = new ArrayList<Video>();
break;
case XmlPullParser.START_TAG:
String name = parser.getName();//获取解析器当前指向的元素的名称
if("video".equals(name)){
video = new Video();
video.setId(new Integer(parser.getAttributeValue(0)));
}
if(video!=null){
if("title".equals(name)){
video.setTitle(parser.nextText());//获取解析器当前指向元素的下一个文本节点的值
}
if("timelength".equals(name)){
video.setTime(new Integer(parser.nextText()));
}
}
break;
case XmlPullParser.END_TAG:
if("video".equals(parser.getName())){
videos.add(video);
video = null;
}
break;
}
eventType = parser.next();
}
return videos;
}
}
D.从网络上获取json数据，然后显示在手机上
public class VideoService {
/**
* 获取最新的视频资讯
* @return
* @throws Exception
*/
public static List<Video> getJSONLastVideos() throws Exception{
List<Video> videos = new ArrayList<Video>();
String path = "http://192.168.1.100:8080/videoweb/video/list.do?format=json";
URL url = new URL(path);
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
conn.setReadTimeout(5*1000);
conn.setRequestMethod("GET");
InputStream inStream = conn.getInputStream();
byte[] data = StreamTool.readInputStream(inStream);
String json = new String(data);
JSONArray array = new JSONArray(json);
for(int i=0 ; i < array.length() ; i++){
JSONObject item = array.getJSONObject(i);
int id = item.getInt("id");
String title = it
补充：移动开发 , Android ,
