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我有抽屉导航 Activity 。我附上了 fragment A(主要 fragment )。在我的抽屉导航菜单中,我还有其他 fragment (B、C、D..)。现在,当我从菜单(B、C、D)转到某个 fragment 并按下后退按钮时,发生的事情是应用程序退出。我想要的是当我按下后退按钮回到 fragment A 时,而不是当我再次按下后退按钮退出应用程序时。
这是我的主要 Activity :
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
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();
// FRAGMENT A starting fagment
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
FragmentMainPage pocetnaFragment = new FragmentMainPage();
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.add(R.id.relativeLayoutZaFragment, pocetnaFragment, "1");
fragmentTransaction.commit();
getSupportActionBar().setTitle("Auto magazin");
ActionBar.LayoutParams p = new ActionBar.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
p.gravity = Gravity.LEFT;
view = getLayoutInflater().inflate(R.layout.action_bar, null);
ActionBar.LayoutParams params = new ActionBar.LayoutParams(
ActionBar.LayoutParams.WRAP_CONTENT,
ActionBar.LayoutParams.MATCH_PARENT,
Gravity.LEFT);
TextView Title = (TextView) view.findViewById(R.id.actionbar_title);
Title.setText("Auto magazin");
getSupportActionBar().setCustomView(view,params);
getSupportActionBar().setDisplayShowCustomEnabled(true); //show custom title
getSupportActionBar().setDisplayShowTitleEnabled(false); //hide the default title
}
boolean doubleBackToExitPressedOnce = false;
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
assert drawer != null;
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
return;
}
else if (doubleBackToExitPressedOnce) {
super.onBackPressed();
return;
}
this.doubleBackToExitPressedOnce = true;
Toast.makeText(this, "Pritisnite još jednom za izlaz", Toast.LENGTH_SHORT).show();
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
doubleBackToExitPressedOnce = false;
}
}, 2000);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item)
{
int id = item.getItemId();
if (id == R.id.podesavanja) {
startActivity(new Intent(this, Podesavanja.class));
return true;
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
// Other fragments, I want to back to Fragment A when click on back button
// when i am in this Fragments
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.pocetna) {
FragmentMainPage fragmentMainPage = new FragmentMainPage() ;
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.relativeLayoutZaFragment
, fragmentMainPage, fragmentMainPage.getTag()).commit();
TextView Title = (TextView) view.findViewById(R.id.actionbar_title);
Title.setText("Auto magazin");
}
else if (id == R.id.info) {
FragmentMenuPages fragmentMenuPages = new FragmentMenuPages();
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.relativeLayoutZaFragment
, fragmentMenuPages, fragmentMenuPages.getTag()).commit();
TextView Title = (TextView) view.findViewById(R.id.actionbar_title);
Title.setText("Info");
Bundle bundle = new Bundle();
bundle.putString("href","http://www.magazinauto.com/category/info/");
bundle.putString("title", "Info");
fragmentMenuPages.setArguments(bundle);
}
else if (id == R.id.testovi) {
FragmentMenuPages fragmentMenuPages = new FragmentMenuPages();
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.relativeLayoutZaFragment
, fragmentMenuPages, fragmentMenuPages.getTag()).commit();
TextView Title = (TextView) view.findViewById(R.id.actionbar_title);
Title.setText("Testovi");
Bundle bundle = new Bundle();
bundle.putString("href", "http://www.magazinauto.com/category/testovi/");
bundle.putString("title", "Testovi");
fragmentMenuPages.setArguments(bundle);
}
else if (id == R.id.promocije) {
FragmentMenuPages fragmentMenuPages = new FragmentMenuPages();
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.relativeLayoutZaFragment
, fragmentMenuPages, fragmentMenuPages.getTag()).commit();
TextView Title = (TextView) view.findViewById(R.id.actionbar_title);
Title.setText("Promocije");
Bundle bundle = new Bundle();
bundle.putString("href", "http://www.magazinauto.com/category/promocije/");
bundle.putString("title", "Promocije");
fragmentMenuPages.setArguments(bundle);
}
else if (id == R.id.svet) {
FragmentMenuPages fragmentMenuPages = new FragmentMenuPages();
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.relativeLayoutZaFragment
, fragmentMenuPages, fragmentMenuPages.getTag()).commit();
TextView Title = (TextView) view.findViewById(R.id.actionbar_title);
Title.setText("Svet");
Bundle bundle = new Bundle();
bundle.putString("href", "http://www.magazinauto.com/category/svet/");
bundle.putString("title", "Svet");
fragmentMenuPages.setArguments(bundle);
}
else if (id == R.id.istorija) {
FragmentMenuPages fragmentMenuPages = new FragmentMenuPages();
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.relativeLayoutZaFragment
, fragmentMenuPages, fragmentMenuPages.getTag()).commit();
TextView Title = (TextView) view.findViewById(R.id.actionbar_title); // OTHER FRAGMENTS
Title.setText("Istorija");
Bundle bundle = new Bundle();
bundle.putString("href", "http://www.magazinauto.com/category/istorija/");
bundle.putString("title", "Istorija");
fragmentMenuPages.setArguments(bundle);
}
else if (id == R.id.tehnika) {
FragmentMenuPages fragmentMenuPages = new FragmentMenuPages();
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.relativeLayoutZaFragment
, fragmentMenuPages, fragmentMenuPages.getTag()).commit();
TextView Title = (TextView) view.findViewById(R.id.actionbar_title);
Title.setText("Tehnika");
Bundle bundle = new Bundle();
bundle.putString("href", "http://www.magazinauto.com/category/tehnika/");
bundle.putString("title", "Tehnika");
fragmentMenuPages.setArguments(bundle);
}
else if (id == R.id.transport) {
FragmentMenuPages fragmentMenuPages = new FragmentMenuPages();
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.relativeLayoutZaFragment
, fragmentMenuPages, fragmentMenuPages.getTag()).commit();
TextView Title = (TextView) view.findViewById(R.id.actionbar_title);
Title.setText("Transport");
Bundle bundle = new Bundle();
bundle.putString("href", "http://www.magazinauto.com/category/transport/");
bundle.putString("title","Transport");
fragmentMenuPages.setArguments(bundle);
}
else if (id == R.id.moto) {
FragmentMenuPages fragmentMenuPages = new FragmentMenuPages();
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.relativeLayoutZaFragment
, fragmentMenuPages, fragmentMenuPages.getTag()).commit();
TextView Title = (TextView) view.findViewById(R.id.actionbar_title);
Title.setText("Moto");
Bundle bundle = new Bundle();
bundle.putString("href", "http://www.magazinauto.com/category/moto/");
bundle.putString("title","Moto");
fragmentMenuPages.setArguments(bundle);
}
else if (id == R.id.lifeStyle) {
FragmentMenuPages fragmentMenuPages = new FragmentMenuPages();
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.relativeLayoutZaFragment
, fragmentMenuPages, fragmentMenuPages.getTag()).commit();
TextView title = (TextView) view.findViewById(R.id.actionbar_title);
title.setText("Lifestyle");
Bundle bundle = new Bundle();
bundle.putString("href", ("http://www.magazinauto.com/category/life-style/"));
bundle.putString("title","Lifestyle");
fragmentMenuPages.setArguments(bundle);
}
else if (id == R.id.daliznate) {
FragmentDaLIPage fragmentMenuPages = new FragmentDaLIPage();
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.relativeLayoutZaFragment
, fragmentMenuPages, fragmentMenuPages.getTag()).commit();
TextView Title = (TextView) view.findViewById(R.id.actionbar_title);
Title.setText("Da li znate?");
Bundle bundle = new Bundle();
bundle.putString("href", "http://www.magazinauto.com/category/da-li-znate/");
bundle.putString("title","Da li znate?");
fragmentMenuPages.setArguments(bundle);
}
else if (id == R.id.redakcija) {
RedakcijaFragment redakcijaFragment = new RedakcijaFragment();
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.relativeLayoutZaFragment
,redakcijaFragment, redakcijaFragment.getTag()).commit();
TextView Title = (TextView) view.findViewById(R.id.actionbar_title);
Title.setText("Redakcija");
}
else if (id == R.id.kontakt) {
KontaktFragment kontaktFragment = new KontaktFragment();
FragmentManager manager = getSupportFragmentManager();
manager.beginTransaction().replace(R.id.relativeLayoutZaFragment
,kontaktFragment, kontaktFragment.getTag()).commit();
TextView Title = (TextView) view.findViewById(R.id.actionbar_title);
Title.setText("Kontakt");
}
else {
return super.onOptionsItemSelected(item);
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
最佳答案
你需要覆盖这个方法
@Override
public void onBackPressed()
{
if(getFragmentManager().getBackStackEntryCount() > 0)
getFragmentManager().popBackStack();
else
super.onBackPressed();
}
并且不要忘记在 fragment 事务上调用 addToBackStack(null)
。
关于android - 如何使用抽屉导航 Activity 中的后退按钮从 fragment 返回到主 fragment ,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/43774290/
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