android How to get values from thread to mainUI

Question

I'm processing some data in the background using runOnUiThread but the value for variable (ishr) which is being used in processing is getting null at the end.

I tried to debug it, every thing works fine and value is present in the runOnUiThread block but it is null when it comes out of it, is there a way to get the values in mainUI ?

public String ishra="";
TextView ish = (TextView) findViewById(R.id.ish);
runOnUiThread(new Runnable(){
            @Override
            public void run(){
                processdata.in.background(result);
            }
        });

ish.setText(ishra);


process.data.in.background(String match)
{
    if (match=="True"){
        getdatafromhttp();
        processdata(resultfromhttp);
    }
}

private void processdata(String data)
{ 
    try
    { 
        JSONObject json = new JSONObject(data);
        JSONObject a = json.getJSONObject("data"); 
        ishra = a.getString("Surprise");
    }
    catch (JSONException e)
    {
        Log.wtf("log", e);
    }
}

What does `processdata.in.background...` do? Where is that code? — Tigger, Nov 23 '16 at 07:39
You appear to have a Context (since you're calling findViewById) so there should be no need to call this as runOnUiThread, you can just invoke `processdata.in.background` directly. — scorpiodawg, Nov 23 '16 at 07:40
processdata.in.background() is parsing JSON data as i was getting error when i put the code directly, after searching i found this [link](http://stackoverflow.com/questions/6343166/how-to-fix-android-os-networkonmainthreadexception) where they suggested many ways to avoid the error i used this one and there was no error .the problem is the value of ishra is getting null when it comes out of the function runOnUithread — reader, Nov 23 '16 at 07:54
@Tigger here is the code for the function processdata.in.backgroundconnect.url.and.get.data(url) ; connect.url.and.get.data(url) ; private void processdata(String data) { try { JSONObject json = new JSONObject(data); JSONObject a = json.getJSONObject("data"); ishra = a.getString("Surprise"); } catch (JSONException e) { Log.wtf("log", e); } } on debugi found the value for ishra to be some string but wehn it goes back to mainUI it is getting null — reader, Nov 23 '16 at 08:04
@Tigger apologies i am new to this forum. i have added the other imp functions to the script — reader, Nov 23 '16 at 08:51

Tigger · Accepted Answer · 2016-11-23T09:13:07.183

Personally I would re-write the code to use AsyncTask or make the following changes:

// ishra is not required any more
//public String ishra="";
TextView ish = (TextView) findViewById(R.id.ish);
runOnUiThread(new Runnable(){
        @Override
        public void run(){
            // Set the text here
            ish.setText(processdata.in.background(result));
        }
    });

// Not required any more
//ish.setText(ishra);

// Return a String 
private String process.data.in.background(String match)
{
    private String result = "";
    if (match=="True"){
        // What does getdatafromhttp() do? It may need to be changed.
        getdatafromhttp();
        result = processdata(resultfromhttp);
    }
    return result;
}

private String processdata(String data)
{
    String result = "";
    try
    { 
        JSONObject json = new JSONObject(data);
        JSONObject a = json.getJSONObject("data"); 
        // Get the result
        result = a.getString("Surprise");
    }
    catch (JSONException e)
    {
        Log.wtf("log", e);
    }
    // Return the result String
    return result;
}

The reason why your code is not working is because you are calling ish.setText(ishra); outside of the runOnUiThread() method. This means the String assigned to ishra within the runOnUiThread() is updated after you have called the setText() method.

You could shift ish.setText(ishra); like so as well:

public void run(){
    processdata.in.background(result);
    ish.setText(ishra);
}

And if you code is solid, that should work too.

thanks, yours is a good solution. before trying urs i was searching for other solution i found ion[link](https://github.com/koush/ion) by kaushikdutta which is simple solution thanks again for the the reply — reader, Nov 26 '16 at 09:00

android How to get values from thread to mainUI

1 Answers1