how to go back to previous fragment when hardware back button is pressed

Question

i am begineer in android development , i would like to configure hardware backbutton to go back to previous fragment and the fragment titles should also change according to the current fragment , here is my Main activity source :

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Toast;


public class MainActivity extends ActionBarActivity implements FragmentDrawer.FragmentDrawerListener {

    private static String TAG = MainActivity.class.getSimpleName();

    private Toolbar mToolbar;
    private FragmentDrawer drawerFragment;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mToolbar = (Toolbar) findViewById(R.id.toolbar);

        setSupportActionBar(mToolbar);
        getSupportActionBar().setDisplayShowHomeEnabled(true);

        drawerFragment = (FragmentDrawer)
                getSupportFragmentManager().findFragmentById(R.id.fragment_navigation_drawer);
        drawerFragment.setUp(R.id.fragment_navigation_drawer, (DrawerLayout) findViewById(R.id.drawer_layout), mToolbar);
        drawerFragment.setDrawerListener(this);

        // display the first navigation drawer view on app launch
        displayView(0);
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        if(id == R.id.action_search){
           Toast.makeText(getApplicationContext(), "Search action is selected!", Toast.LENGTH_SHORT).show();
            return true;
     }

    return super.onOptionsItemSelected(item);
    }

    @Override
    public void onDrawerItemSelected(View view, int position) {
        displayView(position);
    }

    private void displayView(int position) {
        Fragment fragment = null;
        String title = getString(R.string.app_name);
        switch (position) {
            case 0:
                fragment = new HomeFragment();
                title = getString(R.string.title_home);
                break;
            case 1:
                fragment = new MicrosoftDskFragment();
                title = "Microsoft Dsk";
                break;
            case 2:
                fragment = new GoogleDskFragment();
                title = "Google Dsk";
                break;
            case 3:
                fragment = new AppleDskFragment();
                title = "Apple Dsk";
                break;
            case 4:
                fragment = new OthersDskFragment();
                title = "Others Dsk";
                break;
            case 5:
                fragment = new AboutUSFragment();
                title = "About US";
                break;
            default:
                break;
        }


        if (fragment != null) {
            FragmentManager fragmentManager = getSupportFragmentManager();
            FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
            fragmentTransaction.replace(R.id.container_body, fragment);
            fragmentTransaction.addToBackStack(null).commit();

            // set the toolbar title
            getSupportActionBar().setTitle(title);
        }
    }
}

plz hel me in fixing this .

Override onBackpressed() method in your Fragment and popbackstack — SaravInfern, Jul 20 '16 at 05:59
refer here :http://stackoverflow.com/questions/5448653/how-to-implement-onbackpressed-in-android-fragments — SaravInfern, Jul 20 '16 at 06:03

score 4 · Answer 1 · answered Jul 20 '16 at 05:59

You are adding the transaction to the backstack, so all you should need in order to get back to the previous one should be:

FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.popBackstack(null, 0);

You may also consider adding an id for each fragment and passing it when calling

fragmentTransaction.addToBackStack(null).commit();

instead of the null. This way, you will be able to do this:

fragmentTransaction.addToBackStack(myFragmentId).commit();

//Later on...

FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.popBackstack(myFragmentId, 0);

To go back to a specific fragment, not just the last one :-)

What is your import for FragmentManager? – Kelevandos Jul 20 '16 at 07:02 — Kelevandos, Jul 20 '16 at 07:02
import android.support.v4.app.FragmentManager; – Rohith Manchikalapati Jul 20 '16 at 11:46 — Rohith Manchikalapati, Jul 20 '16 at 11:46

score 0 · Answer 2 · edited Jul 20 '16 at 06:07

0

every time when you add a fragment just add addToBackStack() method before commit and then in your activity on back pressed try this

public void onBackPressed() {
                  int count = getSupportFragmentManager().getBackStackEntryCount();

            if (count == 1) {
                goToExitApplication(
                        getResources().getString(R.string.close_app), true);
            } else {
                String title = getSupportFragmentManager().getBackStackEntryAt(count - 2).getName();

                getSupportFragmentManager().popBackStack();

                getSupportActionBar().setTitle(title);

            }
        }

edited Jul 20 '16 at 06:07

Harshad Pansuriya

20,189
8
67
95

answered Jul 20 '16 at 06:04

Mahtab

269
3
11

just remove this method i craeted this according to my need and remove all condition – Mahtab Jul 20 '16 at 06:12
goToExitApplication( getResources().getString(R.string.close_app), true); – Mahtab Jul 20 '16 at 06:19
remove this line and if and else condition as well put code in on back pressed followed by super.onbackpressed – Mahtab Jul 20 '16 at 06:20

Geet Choubey · Answer 3 · 2016-07-20T07:10:35.537

0

I have used this in my code:

@Override
public void onBackPressed() {
    if (getSupportFragmentManager().getBackStackEntryCount() > 0 ){
        getSupportFragmentManager().popBackStack();
    } else {
        super.onBackPressed();
    }
}

To push the Fragment I used:

MyFragment_Items myf = new MyFragment_Items();
transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.container_layout, myf);
transaction.addToBackStack(null);
transaction.commit();

I pushed the fragment here and popped it back onBackPressed.

edited Jul 20 '16 at 07:10

answered Jul 20 '16 at 06:29

Geet Choubey

1,069
7
23

It's a snippet from my code. If it didn't work I wouldn't have added in the answer. -_- – Geet Choubey Jul 20 '16 at 07:11

score 0 · Answer 4 · answered Mar 23 '17 at 10:30

It will Surely work for you If there is any Fragment on the back stack of current fragment , popBackStackImmediate() works..

    @Override
    public void onBackPressed() {
if(getFragmentManager().getBackStackEntryCount() > 0){
     getFragmentManager().popBackStackImmediate();
}
else{
    super.onBackPressed();
}
}

how to go back to previous fragment when hardware back button is pressed

4 Answers4