Android AsyncTask异步处理抓取网页，androidasynctask,Android Asyn

Android AsyncTask异步处理抓取网页，androidasynctask,Android Asyn

Android AsyncTask异步处理抓取网页

/** * * @author yanggang * @see http://blog.csdn.net/sunboy_2050 */public class MainActivity extends Activity {    private EditText metURL;    private TextView mtvPage;    private Button mbtnConn;    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        metURL = (EditText)findViewById(R.id.etURL);        // 输入网址        mbtnConn = (Button)findViewById(R.id.btnConn);      // 连接网站        mtvPage = (TextView)findViewById(R.id.tvPage);      // 显示网页        mbtnConn.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                connURL();            }        });    }    private void connURL(){        URLTask urlTask = new URLTask(this);    // 实例化抽象AsyncTask        urlTask.execute(metURL.getText().toString().trim());    // 调用AsyncTask，传入url参数    }    /** 继承AsyncTask的子类，下载url网页内容 */    class URLTask extends AsyncTask<String, Integer, String> {        ProgressDialog proDialog;        public URLTask(Context context) {            proDialog = new ProgressDialog(context, 0);            proDialog.setButton("cancel", new DialogInterface.OnClickListener() {                @Override                public void onClick(DialogInterface dialog, int which) {                    dialog.cancel();                }            });            proDialog.setOnCancelListener(new DialogInterface.OnCancelListener() {                @Override                public void onCancel(DialogInterface dialog) {                    finish();                }            });            proDialog.setCancelable(true);            proDialog.setMax(100);            proDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);            proDialog.show();        }        @Override        protected void onPreExecute(){            mtvPage.setText(R.string.hello_world);      // 可以与UI控件交互        }        @Override        protected String doInBackground(String... params) {     // 在后台，下载url网页内容            try {                HttpGet get = new HttpGet(params[0]);           // url                HttpResponse response = new DefaultHttpClient().execute(get);                if(response.getStatusLine().getStatusCode() == 200) {       // 判断网络连接是否成功//                  String result = EntityUtils.toString(response.getEntity(), "gb2312");   // 获取网页内容//                  return result;                    HttpEntity entity = response.getEntity();                    long len = entity.getContentLength();       // 获取url网页内容总大小                    InputStream is = entity.getContent();                    ByteArrayOutputStream bos = new ByteArrayOutputStream();                    byte[] buffer = new byte[1024];                    int ch = -1;                    int count = 0;      // 统计已下载的url网页内容大小                    while(is != null &amp;&amp; (ch = is.read(buffer)) != -1 ) {                        bos.write(buffer, 0, ch);                        count += ch;                        if(len > 0) {                            float ratio = count/(float)len * 100;   // 计算下载url网页内容百分比                            publishProgress((int)ratio);    // android.os.AsyncTask.publishProgress(Integer... values)                        }                        Thread.sleep(100);                    }                    String result = new String(bos.toString("gb2312"));                    return result;                }            } catch (Exception e) {                e.printStackTrace();            }            return null;        }        @Override        protected void onProgressUpdate(Integer... values) {    // 可以与UI控件交互            mtvPage.setText("" + values[0]);    // 获取 publishProgress((int)ratio)的values            proDialog.setProgress(values[0]);        }        @Override        protected void onPostExecute(String result) {   // 可以与UI控件交互            mtvPage.setText(result);            proDialog.dismiss();        }    }}