How To Pass A Parameters To AsyncTask (Ksoap2)

问题:

Hi All I want to pass a Variables to AsyncTask

I've This Variables

private static String NAMESPACE = "aaa";
private static String METHOD_NAME = "bbb";
private static String SOAP_ACTION =  NAMESPACE + METHOD_NAME ;
private static String URL = "ccc";

and I've This Task

    public class Login extends AsyncTask<Void, Void, String>
    {
    ProgressDialog progress;
String response = "";
    private ProgressDialog pDialog;
public void onPreExecute() 
  {
    super.onPreExecute();
    pDialog = new ProgressDialog(MainActivity.this);
    pDialog.setMessage("Please Wait");
    pDialog.setIndeterminate(false);
    pDialog.setCancelable(false);
    pDialog.show();
  }
    @Override
protected String doInBackground(Void... arg0)       {
         final SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME);             
         request.addProperty("username", user_name);
         request.addProperty("userpass", user_pass);
         final SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11);
         envelope.setOutputSoapObject(request);
         envelope.dotNet = true;
         try 
            {
                    HttpTransportSE androidHttpTransport = new HttpTransportSE(URL);
                    androidHttpTransport.call(SOAP_ACTION, envelope);                    
                    SoapPrimitive result = (SoapPrimitive) envelope.getResponse();          
                    response = result.toString();
            }
         catch (IOException e) 
            {
             response = "Error In The Operation(1) !!\n Check Internet Connection And TRY AGAIN.";
            }
         catch (Exception e) 
            {
             response = "Error In The Operation(2) !!\n Check Internet Connection And TRY AGAIN.";
            } 
    return response;
    }
@Override
public void onPostExecute(String res)
{
            if(!(res.equalsIgnoreCase("")))
            {
                     if (res.toString().contains(",") == true)
                     {
                   String[] separated = res.split(",");
                   tv.setText(separated[1]);
                   return;
                     }

                 if(res.toString().equals("1"))
                 {
                     res = "Wrong User name OR password ,, TRY AGAIN ..";
                     tv.setText(res);
                     pDialog.dismiss();
                     return;
                 }
                 if(res.toString().equals("2"))
                 {
                     res = "Your Account Is temporarily Blocked ,, Please Call The Admin";
                     tv.setText(res);
                     pDialog.dismiss();
                     return;
                 }
                 if(res.toString().equals("3"))
                 {
                     res = "Error While Retrieve S Information ,, Try Again Later .";
                     tv.setText(res);
                     pDialog.dismiss();
                     return;
                 } 
                tv.setText(res);
                pDialog.dismiss();
            }
}
    }

I Need When I Want To Execute this Taks

To Call It And Pass The Above Variables

Like

new Login().execute();

Make It

new Login().execute(URL,NAMESPACE,METHOD,USERNAME,USERPASS);

With Knolledge That this task return a String :)

AND THE doInBackground MUST HAVE a value for user_name & user_pass Need To Pass It With Execution Call ..

Regards ...

回答1:

Why not create a Constructor for the Login class, like below? In my case, I'm passing an Activity to my AsyncTask so that I can call a callback function when done, but in your case, you could also pass an Array of your Strings.

In this case below, the args array is passed to the class constructor while the params array is passed to the doInBackground function. The MainActivity is passed to the AsyncTask so that the taskDone callback can be called in MainActivity once the task completes.

public class Login extends AsyncTask<String, Void, String>
{
    private MainActivity activity;

    //These private strings are only needed if you require them
    //outside of the doInBackground function.... 
    //If not, just use the params argument of doInBackground by itself
    private String METHODNAME,
    private String NAMESPACE;
    private String SOAPACTION;
    private String USER_NAME;
    private String USER_PASS;

    public Login(String[] args, MainActivity activity) {
        this.NAMESPACE= args[0];
        this.METHODNAME = args[1];
        this.SOAPACTION = args[2];
        this.USER_NAME = args[3];
        this.USER_PASS= args[4];

        this.activity = activity;
    }
    @Override
    protected Void doInBackground(String... params) {
        //Again, use either params local to this function
        //or args local to the entire function... 
        //both would be redundant
        String _NAMESPACE = params[0];
        String _METHODNAME = params[1];
        String _SOAPACTION = params[2];
        String _USER_NAME = params[3];
        String _USER_PASS= params[4];

        //Do background stuff
    }

    protected void onPostExecute() {
        //dismiss progress dialog if needed
        //Callback function in MainActivity to indicate task is done
        activity.taskDone("some string");
    }
}

MainActivity.java

private String[] args= {"mynamespace", "mymethods", "mysoap", "myuser", "mypass"}; //to pass to constructor
private String[] params= {"mynamespace", "mymethods", "mysoap", "myuser", "mypass"}; //to pass to doInBackground

//Pass your args array and the current activity to the AsyncTask
new Login(args, MainActivity.this).execute(params);

//Callback for AsyncTask to call when its completed
public void taskDone(String returnVal) {
    //Do stuff once data has been loaded
    returnText = returnVal;
}

回答2:

Let the class Login extend AsyncTask<String, Void,String> and change doInBackground(Void... params) to doInBackground(String... params). Now you can execute the task in the wanted way, new Login().execute(URL,NAMESPACE,METHOD,USERNAME,USERPASS);, and access the given parameters via the params[] array. This means for your example: params[0] == URL, params[1] == NAMESPACE and so on.

回答3:

The first thing is you need to change

public class Login extends AsyncTask<Void, Void, String>

to

public class Login extends AsyncTask<String, Void, String>

and change

doInBackground(Void...

to

doInBackground(String...

Here is some very helpful documentation on it. If you are still having problems, be a little more specific as to what is or isn't working about it.

The three types used by an asynchronous task are the following:

Params, the type of the parameters sent to the task upon execution.

Progress, the type of the progress units published during the background computation.

Result, the type of the result of the background computation.

These are the paramaters in <String, Void, String>. The first String is what is being passed which is why in doInBackground() you have String... that indicates and array of strings being passed

回答4:

you can pass as many params as you want in execute because doInbackground(Params... params) (think of it as Params[] params) accepts as many parameters as you want as long as they are of the same type.

but if your parameters are of different types (which isn't your case) you need to have them as attributes for asynctask class and pass their values through your asynctask constructor as new login(type1 attr1, type2 attr2).execute(params) :