Android开发——HTTP通讯
2010-05-28 20:03 HalZhang 阅读(6749) 评论(3) 编辑 收藏 举报说Android是一款互联网手机操作系统一点也不过为过。打开G2的"大抽屉”，一大堆的软件，大部分都是需要网络支持才能正常运行的。
曾经和同学说：没有网络支持，G2跟Nokia 1200没啥区别！
既然Android定位为“网络操作系统”，自然提供了很威水的网络访问接口。既有java.net.*,又有org.apache.http.*，在数据处理方面支持json，xml等常用的数据格式。
示例代码如下：
1:
2: public class HttpDemo extends Activity {
3:
4: private static final int MSGWHAT = 0x000000;
5:
6: private TextView textView;
7: private Button btnLink;
8: private EditText etUrl;
9: private String data;
10: /**
11: * 消息控制器，用来更新界面，因为在普通线程是无法用来更新界面的
12: */
13: private Handler handler = new Handler() {
14: @Override
15: public void handleMessage(Message msg) {
16: switch (msg.what) {
17: case MSGWHAT:
18: //设置显示文本
19: textView.setText(data);
20: break;
21: default:
22: break;
23: }
24: }
25: };
26:
27: /** Called when the activity is first created. */
28: @Override
29: public void onCreate(Bundle savedInstanceState) {
30: super.onCreate(savedInstanceState);
31: setContentView(R.layout.main);
32: //注意界面控件的初始化的位置,不要放在setContentView()前面
33: initComponent();
34: btnLink.setOnClickListener(new OnClickListener() {
35:
36: @Override
37: public void onClick(View v) {
38: //可以放在另外的线程完成
39: try {
40: data = getData();
41: } catch (ClientProtocolException e) {
42: data = e.getMessage();
43: } catch (IOException e) {
44: data = e.getMessage();
45: } catch (URISyntaxException e) {
46: data = e.getMessage();
47: }
48: Message msg = new Message();
49: msg.what = MSGWHAT;
50: handler.sendMessage(msg);
51: }
52: });
53: }
54:
55: /**
56: * 初始化界面组件
57: */
58: private void initComponent() {
59: textView = (TextView) findViewById(R.id.text);
60: btnLink = (Button) findViewById(R.id.btn_link);
61: etUrl = (EditText) findViewById(R.id.url);
62: }
63:
64: /**
65: * 取数据
66: * @return
67: * @throws ClientProtocolException
68: * @throws IOException
69: * @throws URISyntaxException
70: */
71: private String getData() throws ClientProtocolException, IOException, URISyntaxException {
72: String urlString = etUrl.getText().toString();
73: return request(urlString);
74: }
75:
76: /**
77: * 发送请求
78: * @param url 请求地址
79: * @return
80: * @throws ClientProtocolException
81: * @throws IOException
82: * @throws URISyntaxException
83: */
84: private String request(String url) throws ClientProtocolException, IOException, URISyntaxException {
85: HttpClient httpClient = new DefaultHttpClient();
86: URI uri = URIUtils.createURI("http", url, -1, null, null, null);
87: HttpGet get = new HttpGet(uri);
88: ResponseHandler<String> responseHandler = new BasicResponseHandler();
89: return httpClient.execute(get, responseHandler);
90: }
91:
92: @Override
93: protected void onDestroy() {
94: super.onDestroy();
95: System.gc();
96: System.exit(0);
97: }
98: }
