Fragment pressing back button

Question

I am now having an activity containing fragments

[1] , [2] , [3] , [4]

If pressing buttons , [3] , it can be redirected to [4]

I would like to imp

Answer 1

Still better solution could be to follow a design pattern such that the back-button press event gets propagated from active fragment down to host Activity. So, it's like.. if one of the active fragments consume the back-press, the Activity wouldn't get to act upon it, and vice-versa.

One way to do it is to have all your Fragments extend a base fragment that has an abstract 'boolean onBackPressed()' method.

@Override
public boolean onBackPressed() {
   if(some_condition)
      // Do something
      return true; //Back press consumed.
   } else {
      // Back-press not consumed. Let Activity handle it
      return false;
   }
}

Keep track of active fragment inside your Activity and inside it's onBackPressed callback write something like this

@Override
public void onBackPressed() {
   if(!activeFragment.onBackPressed())
      super.onBackPressed();
   }
}

This post has this pattern described in detail

Answer 2

if you are using webview inside a fragment than use this in your onCreateView method

webView.setOnKeyListener(new View.OnKeyListener(){

        @Override
        public boolean onKey(View view, int i, KeyEvent keyEvent) {
            if((i==KeyEvent.KEYCODE_BACK)&& webView.canGoBack()){
                webView.goBack();
                return true;
            }
            return false;
        }
    });

and import this class

import android.view.KeyEvent;

Answer 3

You also need to check Action_Down or Action_UP event. If you will not check then onKey() Method will call 2 times.

getView().setFocusableInTouchMode(true);
getView().requestFocus();

getView().setOnKeyListener(new OnKeyListener() {
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {
                if (event.getAction() == KeyEvent.ACTION_DOWN) {
                    if (keyCode == KeyEvent.KEYCODE_BACK) {
                        Toast.makeText(getActivity(), "Back Pressed", Toast.LENGTH_SHORT).show();
                    return true;
                    }
                }
                return false;
            }
        });

Working very well for me.

Answer 4

Easiest way ever:

onResume():

@Override
public void onResume() {
    super.onResume();

    getView().setFocusableInTouchMode(true);
    getView().requestFocus();
    getView().setOnKeyListener(new View.OnKeyListener() {
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {
            if (event.getAction() == KeyEvent.ACTION_UP && keyCode == KeyEvent.KEYCODE_BACK) {
                // handle back button's click listener
                Toast.makeText(getActivity(), "Back press", Toast.LENGTH_SHORT).show();
                return true;
            }
            return false;
        }
    });

}

Edit 1: If fragment having EditText.

private EditText editText;

onCreateView():

editText = (EditText) rootView.findViewById(R.id.editText);

onResume():

@Override
public void onResume() {
    super.onResume();

    editText.setOnKeyListener(new View.OnKeyListener() {
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {
            if (keyCode == KeyEvent.KEYCODE_BACK) {
                editText.clearFocus();
            }
            return false;
        }
    });

    getView().setFocusableInTouchMode(true);
    getView().requestFocus();
    getView().setOnKeyListener(new View.OnKeyListener() {
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {
            if (event.getAction() == KeyEvent.ACTION_UP && keyCode == KeyEvent.KEYCODE_BACK) {
                // handle back button's click listener
                Toast.makeText(getActivity(), "Back press", Toast.LENGTH_SHORT).show();
                return true;
            }
            return false;
        }
    });

}

Note: It will work if you have EditText in fragment.

Done