CODEWITHSUNDEEP
androidmultithreadinghandlernetworkonmainthread
user1254554
user1254554

Reputation: 203

Android timer and NetworkOnMainThreadException

I am using following code to update a list after certain time.

Myactivity {
    setTimer() {
        Runnable  r = new Runnable() {
            run() {
                if(!isListUpdated) {
                    update();//n/w operation
                } else {
                    show();//this is a UI operation
                    listupdated = false;
                }

                Handler.postDelayed(this,next); //repeat after next
            }

            new Thread(r).start();
        }
    } 
}

After 2 - 3 iterations it is giving NetworkOnMainThreadException. Can somebody tell what is wrong in this code?

Upvotes: 0

Views: 739

Answers (5)

ρяσѕρєя K
ρяσѕρєя K

Reputation: 132992

NetworkOnMainThreadException:

The exception that is thrown when an application attempts to perform a networking operation on its main thread.

so you need to Use Thread, runOnUiThread, AsyncTask , Handler , or HandlerThread for Updating UI elements from background Thread.

an example using thread and runOnUiThread :

public void myThread(){
    Thread th=new Thread() {
        @Override
        public void run() {
            try
            {
                while(true) {
                    Current_Activity.this.runOnUiThread( new Runnable() {
                        @Override
                        public void run() {
                    //UPDATE UI FROM HERE
                        }
                    });
                }
            }catch (InterruptedException e) {
                // TODO: handle exception
            }
        }
    };

    th.start();
}

Upvotes: 1

Nikhil Virupakshi
Nikhil Virupakshi

Reputation: 482

I guess you are using honeycomb version, you better use AsyncTask it will solve your problem.

Upvotes: 0

Vipul
Vipul

Reputation: 28093

Consider using runOnUiThread to perform UI operations in Non-UI Thread.

Your code snippet should be something like follows.

Runnable runnable = new Runnable() {

    public void run() {
        if (!isListUpdated) {
            runOnUiThread(new Runnable() {

                public void run() {
                    update(); //n/w operation

                }
            });

        } else {
            runOnUiThread(new Runnable() {

                public void run() {
                    show(); //n/w operation

                }
            });
            listupdated = false;
        }

        handler.postDelayed(runnable, next);
    }
};

Upvotes: 1

AggelosK
AggelosK

Reputation: 4351

This exception usually occurs when you try to perform network operations in the main thread. Use an AsyncTask for your network operations.

Upvotes: 2

AAnkit
AAnkit

Reputation: 27549

You should not do network operation in Main Thread. Create a separate thread and do nw operation there.

You can use AsyncTask, Service or separate thread . Where you ll do network operation. and update via BroadcastReceiver, Handler or AsyncTask.

Read about AsyncTask here

Upvotes: 2

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