Can't create handler inside thread that has not called Looper.prepare()

Question

I get this error "Can't create handler inside thread that has not called Looper.prepare()"

Can you tell me how to fix it?

public class PaymentActivity extends BaseActivity {
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.payment);

    final Button buttonBank = (Button) findViewById(R.id.buttonBank);

    buttonBank.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            progressDialog = ProgressDialog.show(PaymentActivity.this, "",
                    "Redirecting to payment gateway...", true, true);

            new Thread() {
                public void run() {
                    try {
                        startPayment("Bank");
                    } catch (Exception e) {
                        alertDialog.setMessage(e.getMessage());
                        handler.sendEmptyMessage(1);
                        progressDialog.cancel();
                    }
                }
            }.start();
        }

    });

StartPayment Method:

    private void startPayment(String id) {
    Bundle b = getIntent().getExtras();
    final Sail sail = b.getParcelable(Constant.SAIL);

    final Intent bankIntent = new Intent(this, BankActivity.class);

    try {
        Reservation reservation = RestService.createReservation(
                sail.getId(),
                getSharedPreferences(Constant.PREF_NAME_CONTACT, 0));
        bankIntent.putExtra(Constant.RESERVATION, reservation);

        // <workingWithDB> Storing Reservation info in Database
        DBAdapter db = new DBAdapter(this);
        db.open();
        @SuppressWarnings("unused")
        long rowid;
        rowid = db.insertRow(sail.getId(), sail.getFrom(),
                sail.getTo(), sail.getShip(), sail.getDateFrom().getTime(),
                sail.getPrice().toString(), reservation.getId().floatValue());
        db.close();
        // </workingWithDB>

        String html = PaymentService.getRedirectHTML(id, reservation);

        bankIntent.putExtra(Constant.BANK, html);
    } catch (Exception e) {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        AlertDialog alertDialog = builder.create();
        alertDialog.setMessage(e.getMessage());
        alertDialog.show();
    }

    startActivity(bankIntent);
}

Answer 1

You should know that when you try to modify your UI , the only thread who can do that is the UiThread.

So if you want to modify your UI in another thread, try to use the method: Activity.runOnUiThread(new Runnable);

Your code should be like this :

 new Thread() {
    public void run() {  
        YourActivity.this.runOnUiThread(new Runnable(){

             @Override
             public void run(){
                 try {
                      startPayment("Bank");//Edit,integrate this on the runOnUiThread
                 } catch (Exception e) {
                     alertDialog.setMessage(e.getMessage());
                     handler.sendEmptyMessage(1);
                     progressDialog.cancel();
                 } 
            });                
           }
      }
  }.start();

Answer 2

I assume you create a Handler in startPayment() method. You can't do that, as handlers can be created on th UI thread only. Just create it in your activity class.

Answer 3

Instead of new Thread() line, try giving

this.runOnUiThread(new Runnable() {

Answer 4

you cant change any UI in thread you can use runOnUIThread or AsyncTask for more detail about this click here