How to set onclick listener for a button in a fragment in android

Since the button is a part of the fragment's layout, set the listener there:

@Override
public View onCreateView(LayoutInflater inflater,ViewGroup container, Bundle args) {
    View view = inflater.inflate(R.layout.registerblood, container, false);
    String menu = getArguments().getString("Menu");
    location = (Button) view.findViewById(R.id.etlocation);
    location.setText(menu);
    location.setOnClickListener(this);

    return view;
}

@Override
public void onClick(View v) {
    RegisterBlood activity = (RegisterBlood) getActivity();
    // Now you can contact your activity through activity e.g.:
    activity.onKeyDown(KeyEvent.KEYCODE_MENU, null);
}

u need to inflate fragment like this for button click

  View view = inflater.inflate(R.layout.fragment_blank3,
            container, false);
   Button bt1=(Button)view.findViewbyId(R.id.buttton);
   bt1.setOnclick...
   //then return in on create view.
    return view;

// this works good, thankyou

First of all remember to implements the OnClickListener interface:

public class YourClassName extends Fragment implements View.OnClickListener

public Button button;

Then, inside the method OnCreateView, inflate the button and set the listener to it, like this:

@Override
public View onCreateView(LayoutInflater inflater,ViewGroup container, Bundle args) {

    button = (Button) inflater.inflate(R.layout.registerblood, container, false).findViewById(R.id.your_button_id);
    button.setOnClickListener(this);

}

Then @Override the function onClick and do whatever you gotta do:

@Override
public void onClick(View v) {
    //YOUR CODE HERE
}

EDIT If you're simply looking for a FocusListener (in that case your question needs an update) set the listener on your onCreateView method:

your_edittext.setOnFocusChangeListener(new OnFocusChangeListener() {

@Override
public void onFocusChange(View v, boolean hasFocus) {
    if (hasFocus) {
        Toast.makeText(getApplicationContext(), "got the focus", Toast.LENGTH_LONG).show();
        // OPEN THE DRAWER HERE
    } else {
         Toast.makeText(getApplicationContext(), "lost the focus", Toast.LENGTH_LONG).show();
    }
}

or you can implement that listener to your class.