Android: How to get boolean result from AsyncTask?

Question

I want to check Internet connectivity in my App. I found a code but I don't know how to use since I'm really a beginner.

My code :

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
            //I want something like this.
            if(InternetCheck==true){
                Toast("You are connected to internet")
            }
            else{
            Toast("Connection Failed")
            }

    }

 static class InternetCheck extends AsyncTask<Void,Void,Boolean> {

        private Consumer mConsumer;
        public  interface Consumer { void accept(Boolean internet); }

        public  InternetCheck(Consumer consumer) { mConsumer = consumer; execute(); }

        @Override protected Boolean doInBackground(Void... voids) { try {
            Socket sock = new Socket();
            sock.connect(new InetSocketAddress("8.8.8.8", 53), 1500);
            sock.close();
            return true;
        } catch (IOException e) { return false; } }

        @Override protected void onPostExecute(Boolean internet) { mConsumer.accept(internet); }
    }

But I don't know how to get a boolean result from AsyncTask. Please teach me.

score 2 · Accepted Answer · answered Sep 26 '18 at 08:59

2

new InternetCheck(new InternetCheck.Consumer() {
    @Override
    public void accept(Boolean connected) {
        if (connected) {
            Log.d("TAG", "Internet is connected");
        } else {
            Log.d("TAG", "Internet is not connected");
        }     
    }
}).execute();

answered Sep 26 '18 at 08:59

Khemraj Sharma

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It give me error. java.lang.IllegalStateException: Cannot execute task: the task is already running. – uzaysan Sep 26 '18 at 09:09
1

I removed execute() and it work like charm thank you – uzaysan Sep 26 '18 at 09:13
It is using an interface, I use this without execute() – Soon Santos Sep 26 '18 at 09:15

score 0 · Answer 2 · answered Sep 26 '18 at 09:43

You can get result from AsyncTask by using get():

@Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
                Boolean result = new InternetCheck().execute().get();
                if (result == true) {
                    Toast.makeText(this, "You are connected to internet", Toast.LENGTH_LONG).show();
                } else { 
                    Toast.makeText(this, "Connection Failed", Toast.LENGTH_LONG).show();
                }
        }

Or you can check boolean result in AsyncTask in onPostExecute():

@Override 
    protected void onPostExecute(Boolean internet) { 
        mConsumer.accept(internet);
        if (internet == true) {
                    Toast.makeText(YourActivity.this, "You are connected to internet", Toast.LENGTH_LONG).show();
                } else { 
                    Toast.makeText(YourActivity.this, "Connection Failed", Toast.LENGTH_LONG).show();
                }
    }

Android: How to get boolean result from AsyncTask?

2 Answers2