本文實例講述了Android開發(fā)之HttpClient異步請求數(shù)據(jù)的方法。分享給大家供大家參考，具體如下：
前面一篇Android開發(fā)筆記之:AsyncTask的應(yīng)用較為詳細(xì)的講述了Asynctask的原理與應(yīng)用，這里來結(jié)合使用一下HttpClient與Asynctask~
代碼編寫如下：
服務(wù)器代碼我就不寫出來了，就是一個用戶名和密碼~
1.寫一個類HttpClientUtil，來實現(xiàn)HttpClient對象的創(chuàng)建并且返回HttpResponse對象
public class HttpClientUtil { private static HttpClient httpClient; static{ //1.創(chuàng)建HttpClient對象 httpClient=new DefaultHttpClient(); } //2.執(zhí)行該方法返回一個HttpResponse public static HttpResponse sendRequest(String url,List<NameValuePair>list){ HttpResponse response=null; try { if(list==null){ //Get方式 HttpGet get=new HttpGet(url); response=httpClient.execute(get); }else{ //Post方式 HttpPost post=new HttpPost(url); //3.對于HttpPost對象而言，可調(diào)用setEntity(HttpEntity)方法設(shè)置請求參數(shù)。 //4.使用HttpEntity下的UrlEncodedFormEntitiy對象傳入一個放入BasicNameValuePair的集合中提交的數(shù)據(jù)。 post.setEntity(new UrlEncodedFormEntity(list)); response=httpClient.execute(post); } }catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return response; }}get方式和post方式就是有點不一樣~它們請求數(shù)據(jù)的時候get方式?jīng)]有NameValuePair~
2.寫一個監(jiān)聽接口ResponseListener，來實現(xiàn)監(jiān)聽服務(wù)器返回的數(shù)據(jù)
public interface ResponseListener { public void onResult(String msg); public void onError(String msg);}3.寫下MainActivity中的get方法提交和post方法提交
//get方式public void get(View view){ String nameTe=name.getText().toString(); String pwdTe=pwd.getText().toString(); HttpClientTask task=new HttpClientTask(this); //要傳進(jìn)去的參數(shù) task.execute(BASIC+"?name="+nameTe+"&pwd="+pwdTe);}//post方式public void post(View view){ String nameTe=name.getText().toString(); String pwdTe=pwd.getText().toString(); List<NameValuePair>list=new ArrayList<NameValuePair>(); list.add(new BasicNameValuePair("name", nameTe)); list.add(new BasicNameValuePair("pwd", pwdTe)); HttpClientTask task=new HttpClientTask(list, this); task.execute(BASIC);}public static final String BASIC="http://192.168.207.1:8090/ConnectionServlet/LoginServlet";
看圖就知道，我又寫了一個類HttpClientTask~
4.編寫HttpClientTask，讓其繼承Asynctask~
/* * Params:輸入?yún)?shù),如果不需要傳遞參數(shù),則直接設(shè)為Void即可 --String * Progress:子線程執(zhí)行的百分比 --Void * Result:返回的參數(shù) --HttpResonse */public class HttpClientTask extends AsyncTask<String, Void, HttpResponse>{ private List<NameValuePair>list; private ResponseListener listener; //Get請求 public HttpClientTask(ResponseListener listener) { super(); // TODO Auto-generated constructor stub this.listener=listener; } //Post請求 public HttpClientTask(List<NameValuePair>list,ResponseListener listener) { super(); // TODO Auto-generated constructor stub this.list=list; this.listener=listener; } //doInBackground有返回值,并且返回值是由result決定的, //參數(shù)列表首先是一個可變長參數(shù),是由Params決定的 //執(zhí)行時機:在onPreExecute方法執(zhí)行后馬上執(zhí)行,該方法運行在后線程中 //作用:主要負(fù)責(zé)執(zhí)行那些很耗時的后臺處理工作,可以調(diào)用publishProgress方法來更新實時的任務(wù)進(jìn)度 @Override protected HttpResponse doInBackground(String... params) { // TODO Auto-generated method stub HttpResponse response; //這里會返回一個response response=HttpClientUtil.sendRequest(params[0], list); return response; } //參數(shù)是由result決定的 //作用:后臺的計算結(jié)果將顯示出來 //可以進(jìn)行一些結(jié)束處理 @Override protected void onPostExecute(HttpResponse result) { // TODO Auto-generated method stub String msg; try { //result是響應(yīng)內(nèi)容 //用EntityUtils.toString(HttpEntity,"編碼方式") //將其轉(zhuǎn)成為字符串 msg=EntityUtils.toString(result.getEntity(), "UTF-8"); if(listener!=null){ listener.onResult(msg); } }catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); listener.onResult("出錯了"); } super.onPostExecute(result); }}代碼寫的很清楚，我就不一一解釋了~
最后在onPostExecute方法后面調(diào)用了接口中的倆個方法~
這倆個方法在MainActivity中被重寫了~
@Override public void onResult(String msg) { // TODO Auto-generated method stub System.out.println(msg); } @Override public void onError(String msg) { // TODO Auto-generated method stub System.out.println("出錯了"); } 說實話，服務(wù)器返回的數(shù)據(jù)就是成功或者失敗~
如果那個監(jiān)聽器為空的話，就代表鏈接錯誤，后臺會打印出“出錯了”
否則會打印出“成功”或者“失敗”~
MainActivity完整代碼：
public class MainActivity extends Activity implements ResponseListener{ private EditText name,pwd; public static final String BASIC="http://192.168.207.1:8090/ConnectionServlet/LoginServlet"; //get方式 public void get(View view){ String nameTe=name.getText().toString(); String pwdTe=pwd.getText().toString(); HttpClientTask task=new HttpClientTask(this); //要傳進(jìn)去的參數(shù) task.execute(BASIC+"?name="+nameTe+"&pwd="+pwdTe); } //post方式 public void post(View view){ String nameTe=name.getText().toString(); String pwdTe=pwd.getText().toString(); List<NameValuePair>list=new ArrayList<NameValuePair>(); list.add(new BasicNameValuePair("name", nameTe)); list.add(new BasicNameValuePair("pwd", pwdTe)); HttpClientTask task=new HttpClientTask(list, this); task.execute(BASIC); } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); name=(EditText) findViewById(R.id.name); pwd=(EditText) findViewById(R.id.pwd); } @Override public void onResult(String msg) { // TODO Auto-generated method stub System.out.println(msg); } @Override public void onError(String msg) { // TODO Auto-generated method stub System.out.println("出錯了"); }}附：完整實例代碼點擊此處本站下載。
希望本文所述對大家Android程序設(shè)計有所幫助。
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