Enabling Buttons after doInBackground finishes

Question

I would like to enable a few buttons from my main activity once the stuffs from doInBackground() is finished! Can someone please let me know how to do that?

I can't use findViewByID() for making he button visible from the AsyncTask class as it's not an activity class! :/

Why don't you just pass a reference of your activity to your AsyncTask? — asgoth, Dec 28 '12 at 10:29
@Adil Soomro I am sorry, thats a little too much complicated for me! Can you please describe it to fit in my scenario? — defiant, Dec 28 '12 at 13:41

score 5 · Answer 1 · answered Dec 28 '12 at 10:29

5

Do Like this...

Define a method which enables the Buttons.
Then on PostExecute() on AsyncTask, call that method

answered Dec 28 '12 at 10:29

Renjith

5,783
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So I have to define the method in MainActivity.java and call it from AsyncTask PostEXecute()? – defiant Dec 28 '12 at 10:33
4

yes.. Make the buttons global so that you will get it anywhere in the activity. – Renjith Dec 28 '12 at 10:35
Its not working, I need to pass the view to the method which enables the buttons from the MainActivity right? But this method is being called from the AsyncTask class, so how do I do this? – defiant Dec 28 '12 at 11:44
you don't have to pass the view to `Asynctask` for just enabling it. Just call the method on `onPostExecute()`. in the method, enable the buttons. tats all... – Renjith Dec 28 '12 at 11:48
Check this: http://pastie.org/private/n9zyelt5zsumjl0et464q This gives me an error which makes the application to force close. Error Log: http://pastie.org/5588296 – defiant Dec 28 '12 at 12:09
Are you sure I don't have to pass view. I am using findViewId, so I think I am doing it the wrong way! :/ – defiant Dec 28 '12 at 12:33
try calling just the method without the `activity` tag i.e just `setButtonsVisible` – Renjith Dec 28 '12 at 15:46

score 0 · Answer 2 · answered Dec 28 '12 at 10:31

there is one callback onPostExecution(...) { } of AsynTask class use this method to UI stuff,for enable,disable button just write this way in onPostExcustion(...)

runOnUiThread(new Runnable() {

    @Override
    public void run() {
        // TODO Auto-generated method stub

    }
});

also make sure this method only available in activity class

thank you

laplasz · Answer 3 · 2012-12-28T10:55:38.430

your class which extends AsyncTask you can push your context into it, when calling the execute().

private class RegisterUser extends AsyncTask<String,String,String> {

    private ListActivity activity;
    public RegisterUser(ListActivity activity) {
        this.activity = activity;
    }

    protected void onPostExecute(JSONObject json) {
        activity.editText = (EditText)activity.findViewById(R.id.editText1);
        //or
        activity.enableButton();
    }
}

and call the execute from the Activity like this:

new RegisterUser(this).execute(new String[] {"param"});

or you can define the AsyncTask class inside your Activity class - where you can reach everything. more info Lars Vogel - Android Threads, Handlers and AsyncTask

score 0 · Answer 4 · answered Dec 28 '12 at 10:49

Follow this way:

[1] Create your AsyncTask :

public class performBackgroundTask extends AsyncTask<Void, Void, Void> {
    ProgressDialog Dialog = new ProgressDialog(HotUsers.this);
    protected void onPreExecute() {
        Dialog.setMessage("Loading Hot Users..."); 
        Dialog.show();      
    }

    protected void onPostExecute(Void unused) {
        if(Dialog.isShowing()) 
            Dialog.dismiss();
        set_details_on_screen();

    }

    @Override
    protected Void doInBackground(Void... params) {         
        get_details_from_server(); // get data like userid,username,userdesc etc...
        return null;
    }
}

[2] That will call function to proceed for UI changes.

public void set_details_on_screen()
 {
    if(userid > 0 )
        handler_default.sendEmptyMessage(0);
    else
            handler_default.sendEmptyMessage(1);

 }

[3] At last your UI changes will be reflected on screen with this Handler.

private Handler handler_default = new Handler() {
    public void handleMessage(Message msg) {
        switch (msg.what) {
        case 0: {
            textuserid = (TextView) findViewById(R.id.userid);
            textusername = (TextView) findViewById(R.id.username);
            textuserdesc = (TextView) findViewById(R.id.userdesc);

            textuserid.setText(userid);
            textusername.setText(username);
            textuserdesc.setText(userdesc);

            break;
        }
        case 1: {
            Toast.makeText(getApplicationContext(),"Error",Toast.LENGTH_LONG).show();
            break;
        }

       }
    }
};

Thanks.

Enabling Buttons after doInBackground finishes

4 Answers4