使用HttpClient和Progressbar的Asynctask

Question

我正在尝试使用Asynctask和进度条使我的HttpClient正常工作。 我已经有了这个Asynctask代码：

private class httpClient extends AsyncTask<String, Boolean, String> {

private HttpClient httpClient = getHttpClient();

@Override
protected String doInBackground(String... params) {
    publishProgress(true); 
    // Do the usual httpclient thing to get the result
    return null;
} 

@Override 
protected void onProgressUpdate(Boolean... progress) { 
    // line below coupled with  
    //    getWindow().requestFeature(Window.FEATURE_INDETERMINATE_PROGRESS)  
    //    before setContentView  
    // will show the wait animation on the top-right corner 
    AndroidLogin.this.setProgressBarIndeterminateVisibility(progress[0]); 
} 

@Override 
protected void onPostExecute(String result) { 
    publishProgress(false); 
    // Do something with result in your activity 
} 

}

我想知道如何在Asynctask中正确地放置以下代码，并使进度条正常工作。有人可以帮忙吗？

/******* INPUT USERNAME AND PASSWORD *******/
        EditText uname = (EditText)findViewById(R.id.txt_username); // user input through EditText
        String username = uname.getText().toString();
        EditText pword = (EditText)findViewById(R.id.txt_password); // password input through EditText
        String password = pword.getText().toString();

/******* INSTANTIATE THE CUSTOM HTTPCLIENT *******/
        HttpClient httpClient = getHttpClient();
        HttpPost request = new HttpPost("https://xxx"); 

        List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(); 
        nameValuePairs.add(new BasicNameValuePair("usr_name", username)); 
        nameValuePairs.add(new BasicNameValuePair("usr_password", password)); 
        request.setEntity(new UrlEncodedFormEntity(nameValuePairs));

/******* EXECUTE HTTPCLIENT *******/
        try  
        { 
        HttpResponse response = httpClient.execute(request); 

/******* READ CONTENT IN BUFFER *******/
        InputStream inputStreamActivity = response.getEntity().getContent();  
        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStreamActivity));
        StringBuilder sb = new StringBuilder();
        String line = null;

        while ((line = reader.readLine()) != null) {
        sb.append(line + "\n");
        }
/******* CLOSE CONNECTION AND STREAM *******/
        System.out.println(sb);
            inputStreamActivity.close();
        httpClient.getConnectionManager().shutdown();

- Lars

Answer 1

我找到了解决方案。我需要将Textfields包含在Asynctask中，以避免异常。

EditText uname = (EditText)findViewById(R.id.txt_username);
EditText pword = (EditText)findViewById(R.id.txt_password);

我决定使用ProgressDialog而不是ProgressBar，需要添加以下内容：

//Create a Progressdialog
ProgressDialog pd = new ProgressDialog(MyApp.this);

@Override 
    protected void onPreExecute()  
    { 
        //Set the Progressdialog
        pd.setProgressStyle(ProgressDialog.STYLE_SPINNER); 
        pd.setMessage("Getting data....");
                 }

 @Override
    protected void onProgressUpdate(Integer... args) { 
           //Update the Progressdialog
           pd.setProgress(args[0]); 
           } 

  @Override 
    protected void onPostExecute(String result) { 
        //Dismiss Progressdialog
        pd.dismiss();
                 }

就是这样。

- Lars

Answer 2

尝试在onPreExecute中使用ProgressBar init以及其他与你的重要事项无关的事情：

@Override
protected void onPreExecute() 
{
     publishProgress(true); 
}

@Override
protected String doInBackground(String... params)
{
     funtiontoallthatbigcodeorcodeitselfhere(); 
}

...

- A.Quiroga

---

我还需要在以下代码周围添加try-catch块： nameValuePairs.add(new BasicNameValuePair("usr_password", password)); - Lars

以下是来自Logcat的错误信息： ERROR/AndroidRuntime(8675): java.lang.RuntimeException: 无法实例化活动ComponentInfo{com.sencide/com.sencide.AndroidLogin}：java.lang.NullPointerException - Lars

A.Quiroga，你还在吗？ - Lars

好的，但请将翻译后的文本放在答案中，以帮助其他遇到相同问题的人。 - A.Quiroga

我必须等待8个小时，因为我的声望不到100。 但是我会发布解决方案。 - Lars