how to add runOnUiThread() in my Activity

Question

I added the AsyncTask to offload network operations to a background thread.I need to make sure the UI operations are on the UI thread.So i want to Use runOnUiThread() in my Acti

Answer 1

I added the AsyncTask to offload network operations to a background thread.I need to make sure the UI operations are on the UI thread.So i want to Use runOnUiThread() in my Activity.

Ugh! No!!! Every method of AsyncTask runs on the UI Thread except for doInBackground(). So do your network operations in doInBackground() and update the UI in onPostExecute() or in onProgressUpdate() by calling publishProgress() from doInBackground().

Do not use runOnUiThread() with AsyncTask. There is no reason, at least known to me, to use that with AsyncTask since it has methods that already run on the UI Thread. I have never seen it do anything but cause trouble.

You can either call publishProgress() from your loop and update your TextView in onProgressUpdate() or add the values to an ArrayList and update in onProgressUpdate().

Please read the docs several times. AsyncTask is a bit tricky at first but once you learn what it does then it can be a beautiful thing.

Edit

Create an instance of your AsyncTask and pass your Activity Context to it

Scan myScan = new scan(this); // pass the context to the constructor
myScan.execute();

Then create a constructor in your AsyncTask and have it accept a Context.

public class scan extends AsyncTask<String, Integer, String> 
{

     public Object WIFI_SERVICE;
     public Context context;   // Context variable

     public scan(Context c)  // constructor to take Context
     {
         context = c;   // intialize your Context variable
     }

Now use that variable

    @Override
    protected String doInBackground(String... params) 
    {
        wifiApManager = new WifiApManager(context);  // use the variable here
        return null;
    }

Another Edit

class scan extends AsyncTask<String, Void, Void> {
     ArrayList<ClientScanResult> clients;
     Context context;

...

then initialize your `clients` in `doInBackground()`

clients = wifiApManager.getClientList(false);

change onPostExecute() to not accept anything

protected void onPostExecute(Void result){

and put your code that updates the TextView in there.

Answer 2

You should not be accessing any UI elements within doInBackground, This method runs in background thread. What you should do is override onPostExecute() method and access your TextView there. onPostExecute runs in UI thread, so you don't need to call runOnUiThread()