创建一个AsyncTask并将代码放在doInBackground方法中

Question

我发现下面的代码来执行HTTP POST。它说我不直接在UI/Main Thread中运行这些代码。创建一个AsyncTask并将代码放在doInBackground方法中。如何使它在asynctask下运行。

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Answer 1

您可以尝试像下面：

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.mail_activity); 

    mToolbar = (Toolbar) findViewById(R.id.toolbar); 

    setSupportActionBar(mToolbar); 
    getSupportActionBar().setDisplayHomeAsUpEnabled(true); 
    getSupportActionBar().setHomeButtonEnabled(true); 


    String dataUrl = "http://example.com"; 
    String dataUrlParameters = "email="+"pp@gmail.com"+"&name="+"priyabrat"+"&message="+"Message_here"; 

    // Call background operation. 
    new NetworkOperation().execute(dataUrl, dataUrlParameters); 
} 


private class NetworkOperation extends AsyncTask<String, Void, String> { 

    @Override 
    protected String doInBackground(String... params) { 
     String result = doNetworkOperation(params[0], params[1]); 

     // more task if you have 
     return result; 
    } 

    @Override 
    protected void onPostExecute(String result) { 

    } 
} 

private String doNetworkOperation(String dataUrl, String dataUrlParameters) { 
    URL url; 
    HttpURLConnection connection = null; 
    String responseStr = ""; 
    try { 
     // Create connection 
     url = new URL(dataUrl); 
     connection = (HttpURLConnection) url.openConnection(); 
     connection.setRequestMethod("POST"); 
     connection.setRequestProperty("Content-Type","application/x-www-form-urlencoded"); 
     connection.setRequestProperty("Content-Length","" + Integer.toString(dataUrlParameters.getBytes().length)); 
     connection.setRequestProperty("Content-Language", "en-US"); 
     connection.setUseCaches(false); 
     connection.setDoInput(true); 
     connection.setDoOutput(true); 
     // Send request 
     DataOutputStream wr = new DataOutputStream(
     connection.getOutputStream()); 
     wr.writeBytes(dataUrlParameters); 
     wr.flush(); 
     wr.close(); 
     // Get Response 
     InputStream is = connection.getInputStream(); 
     BufferedReader rd = new BufferedReader(new InputStreamReader(is)); 
     String line; 
     StringBuffer response = new StringBuffer(); 
     while ((line = rd.readLine()) != null) { 
      response.append(line); 
      response.append('\r'); 
     } 
     rd.close(); 
     responseStr = response.toString(); 
     Log.d("Server response",responseStr); 

    } catch (Exception e) { 

     e.printStackTrace(); 

    } finally { 

     if (connection != null) { 
      connection.disconnect(); 
     } 
    } 
    return responseStr; 
}