android http发布asynctask

Question

请问任何人都可以告诉我如何使用AsyncTask在后台使用http帖子以及如何将参数传递给AsyncTask？我发现的所有示例对我来说都不够清楚,而且它们是关于下载文件的.

我在我的主要活动中运行此代码,我的问题是当代码将信息发送到服务器时,应用程序速度减慢,好像它被冻结了2到3秒,然后它继续正常工作,直到下一次发送.此http帖子向服务器发送四个变量(book,libadd和time),第四个是固定的(名称)

提前致谢

    public void  SticketFunction(double book, double libadd, long time){
        Log.v("log_tag", "%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% SticketFunction()");
        //HttpClient
        HttpClient nnSticket = new DefaultHttpClient();
        //Response handler
        ResponseHandler<String> res = new BasicResponseHandler();

        HttpPost postMethod = new HttpPost("http://www.books-something.com");


        try {
            List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(5);

            nameValuePairs.add(new BasicNameValuePair("book", book+""));

            nameValuePairs.add(new BasicNameValuePair("libAss", libass+""));

            nameValuePairs.add(new BasicNameValuePair("Time", time+""));

            nameValuePairs.add(new BasicNameValuePair("name", "jack"));
            //Encode and set entity
            postMethod.setEntity(new UrlEncodedFormEntity(nameValuePairs, HTTP.UTF_8));
            //Execute 
            //manSticket.execute(postMethod);
            String response =Sticket.execute(postMethod, res).replaceAll("<(.|\n)*?>","");
            if (response.equals("Done")){

                //Log.v("log_tag", "!!!!!!!!!!!!!!!!!! SticketFunction got a DONE!");

            }
            else Log.v("log_tag", "!!!!!!!?????????? SticketFunction Bad or no response: " + response);

        } catch (ClientProtocolException e) {  
            // TODO Auto-generated catch block 
            //Log.v("log_tag", "???????????????????? SticketFunction Client Exception");
        } catch (IOException e) {  
            // TODO Auto-generated catch block
            //Log.v("log_tag", "???????????????????? IO Exception");
        } 
    }

}

Answer 1

首先,你把一个类如下:

public class AsyncHttpPost extends AsyncTask<String, String, String> {
    interface Listener {
        void onResult(String result);
    }
    private Listener mListener;
    private HashMap<String, String> mData = null;// post data

    /**
     * constructor
     */
    public AsyncHttpPost(HashMap<String, String> data) {
        mData = data;
    }
    public void setListener(Listener listener) {
        mListener = listener;
    }

    /**
     * background
     */
    @Override
    protected String doInBackground(String... params) {
        byte[] result = null;
        String str = "";
        HttpClient client = new DefaultHttpClient();
        HttpPost post = new HttpPost(params[0]);// in this case, params[0] is URL
        try {
            // set up post data
            ArrayList<NameValuePair> nameValuePair = new ArrayList<NameValuePair>();
            Iterator<String> it = mData.keySet().iterator();
            while (it.hasNext()) {
                String key = it.next();
                nameValuePair.add(new BasicNameValuePair(key, mData.get(key)));
            }

            post.setEntity(new UrlEncodedFormEntity(nameValuePair, "UTF-8"));
            HttpResponse response = client.execute(post);
            StatusLine statusLine = response.getStatusLine();
            if(statusLine.getStatusCode() == HttpURLConnection.HTTP_OK){
                result = EntityUtils.toByteArray(response.getEntity());
                str = new String(result, "UTF-8");
            }
        }
        catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        catch (Exception e) {
        }
        return str;
    }

    /**
     * on getting result
     */
    @Override
    protected void onPostExecute(String result) {
        // something...
        if (mListener != null) {
            mListener.onResult(result)
        }
    }
}

现在.你只需写下如下几行:

HashMap<String, String> data = new HashMap<String, String>();
data.put("key1", "value1");
data.put("key2", "value2");
AsyncHttpPost asyncHttpPost = new AsyncHttpPost(data);
asyncHttpPost.setListener(new AsyncHttpPost.Listener(){
    @Override
    public void onResult(String result) {
        // do something, using return value from network
    }
});
asyncHttpPost.execute("http://example.com");

Answer 2

首先，我不建议在 AsyncTask 中执行 Http 请求，您最好尝试使用 Service。回到关于如何在声明 AsyncTask 时将参数传递到 AsyncTask 的问题，您可以像这样定义AsyncTask的每个对象类。

public AsyncTask <Params,Progress,Result> {

}

所以在你的任务中你应该这样

public MyTask extends<String,Void,Void>{

public Void doInBackground(String... params){//those Params are String because it's declared like that

}

}

使用起来非常简单

new MyTask().execute("param1","param2","param3")