Android ; Confirm app exit
final String phoneNumber;
phoneNumber = "5555555555";

ImageButton callButton = (ImageButton)findViewById(R.id.btnCall);

callButton.setOnClickListener(new OnClickListener(){
    public void onClick(View v) {
        try {
            Intent callIntent = new Intent(Intent.ACTION_DIAL);
            callIntent.setData(Uri.parse("tel:"+phoneNumber));
            startActivity(callIntent);
        } catch (ActivityNotFoundException activityException) {
            Log.e("Calling a Phone Number", "Call failed", activityException);
        }
    }
});

callButton.setOnClickListener(new OnClickListener(){
        public void onClick(View v) {
            OnClickListener listener = new OnClickListener(){
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    if(which == Dialog.BUTTON_POSITIVE)
                    {
                        try {
                            Intent callIntent = new Intent(Intent.ACTION_DIAL);
                            callIntent.setData(Uri.parse("tel:"+phoneNumber));
                            startActivity(callIntent);
                        } catch (ActivityNotFoundException activityException) {
                            Log.e("Calling a Phone Number", "Call failed", activityException);
                        }
                    }
                }
            };

            new AlertDialog.Builder(v.getContext())
            .setMessage("Are you sure you want to leave the application?")
            .setPositiveButton("Yes", listener)
            .setNegativeButton("No", listener)
            .show();
        }
    }

AlertDialog.Builder alert = new AlertDialog.Builder(this);

alert.setTitle("Title");
alert.setMessage("Message");

// Set an EditText view to get user input
final EditText input = new EditText(this);
alert.setView(input);

alert.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
  String value = input.getText();
  // Do something with value!
  }
});

alert.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
  public void onClick(DialogInterface dialog, int whichButton) {
    // Canceled.
  }
});

alert.show();