使用向上按钮导航回相应的片段

Question

I have implemented Bottom Navigation with three top level destinations (one fragment for each destination): Home , Search and Settings respectively. In Search fragment I had search button, which up on click, takes to another activity say ActivityX. When navigated back from ActivityX using up button, it navigates to Home instead of Search. I want the up button navigate to Search. How to achieve it?

My MainActivity:

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

    sp=getSharedPreferences("login_details",MODE_PRIVATE);
    if(!sp.getBoolean("login_status", false)){
        isLoggedIn=false;
    }
    else
        isLoggedIn=true;

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


    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.setDrawerListener(toggle);
    toggle.syncState();

    NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);

    BottomNavigationView bottomNav = (BottomNavigationView) findViewById(R.id.navigation);
    fragmentManager=getSupportFragmentManager();
    android.support.v4.app.FragmentTransaction ft1=fragmentManager.beginTransaction();
    ft1.add(R.id.container,new HomeFragment());
    ft1.commit();
    updateToolbarText("Home");
    bottomNav.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            if(item.getItemId()==R.id.action_home){
                fragmentManager=getSupportFragmentManager();
                android.support.v4.app.FragmentTransaction ft1=fragmentManager.beginTransaction();
                ft1.replace(R.id.container,new HomeFragment());
                ft1.commit();

                updateToolbarText("Home");

            }
            if(item.getItemId()==R.id.action_search){
                fragmentManager=getSupportFragmentManager();
                android.support.v4.app.FragmentTransaction ft2=fragmentManager.beginTransaction();
                ft2.replace(R.id.container,new SearchFragment());
                ft2.commit();
                MainActivity.super.onBackPressed();
                updateToolbarText("Search");


            }
            if(item.getItemId()==R.id.action_settings){
                fragmentManager=getSupportFragmentManager();
                android.support.v4.app.FragmentTransaction ft3=fragmentManager.beginTransaction();
                ft3.replace(R.id.container,new SettingsFragment());
                ft3.commit();
                updateToolbarText("Settings");
            }
            return true;

        }

    });

}

Answer 1

In ActivityX create intent and put string in it. The string contains information where are you comming from, ie. Search, and then startActivity(ActivityX, MainActivity).

Then in MainActivity override onResume method. In this method check if intent contains specific string you put in ActivityX. If it contains that string, start the SearchFragment

Here is my example:

ActivityX:

@Override
public void onBackPressed() {
    super.onBackPressed();
    Intent intent = new Intent(FragmentTrainingDetail.this, MainActivity.class);
    intent.putExtra("TAG", "FragmentMyTraining");
    startActivity(intent);
    finish();
}

MainActivity:

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

    Intent intent = getIntent();

    if (intent.hasExtra("FragmentMyTraining")) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.add(R.id.content_frame, new FragmentMyTraining());
        fragmentTransaction.addToBackStack("my");
        fragmentTransaction.commit();
    } else if (intent.hasExtra("FragmentPopularTraining")) {
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.add(R.id.content_frame, new FragmentPopularTraining());
        fragmentTransaction.addToBackStack("pop");
        fragmentTransaction.commit();
    }
}