我在我的应用程序中使用抽屉导航，一切正常，问题是 onbackpress 我的应用程序正在关闭，没有应用程序崩溃，只是我的应用程序正在关闭
以下是我的代码和屏幕截图，有人可以帮忙吗？
主要 Activity
@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 FriendsFragment();
title = getString(R.string.title_friends);
break;
case 2:
fragment = new MessagesFragment();
title = getString(R.string.title_messages);
break;
case 3:
fragment = new Profiles();
title = getString(R.string.title_pro);
break;
case 4:
fragment = new AboutUsFragment();
title = getString(R.string.title_aboutus);
break;
case 5:
fragment = new FAQ();
title = getString(R.string.title_faq);
break;
case 6:
fragment = new Privacypolicy();
title = getString(R.string.title_privacypolicy);
break;
case 7:
fragment = new ContactUs();
title = getString(R.string.title_contacts);
break;
case 8:
// session.logoutUser();
LoginManager.getInstance().logOut();
// Intent intent=new Intent(MainActivity.this,LoginPage.class);
// startActivity(intent);
title = getString(R.string.title_logout);
break;
default:
break;
}
if (fragment != null) {
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.container_body, fragment);
fragmentTransaction.commit();
getSupportActionBar().setTitle(title);
}
}
/* @Override
public void onBackPressed() {
int count = getFragmentManager().getBackStackEntryCount();
if (count == 0) {
super.onBackPressed();
//additional code
} else {
getFragmentManager().popBackStack();
}
}*/
@Override
public void onBackPressed(){
FragmentManager fm = getSupportFragmentManager();
if (fm.getBackStackEntryCount() > 1) {
Log.i("MainActivity", "popping backstack");
fm.popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
} else {
Log.i("MainActivity", "nothing on backstack, calling super");
super.onBackPressed();
}
}
}
首页 fragment .java
public class HomeFragment extends Fragment {
ExpandableListAdapter listAdapter;
ExpandableListView expListView;
List<String> listDataHeader;
HashMap<String, List<String>> listDataChild;
private FragmentTabHost tabHost;
private SearchView searchView;
// private String strtext;
// private String FBIDs;
// private String GIDs;
public HomeFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
tabHost = new FragmentTabHost(getActivity());
tabHost.setup(getActivity(), getChildFragmentManager(), R.layout.my_parent_fragment);
// strtext = getArguments().getString("user_login_id");
// System.out.println("<<<<<<<<<<<<<< Session ID : " + strtext);
Bundle arg1 = new Bundle();
arg1.putInt("Arg for Frag1", 1);
/* if(strtext!=null) {
arg1.putString("user_logid", strtext);
}*/
tabHost.addTab(tabHost.newTabSpec("one").setIndicator(getTabIndicator(tabHost.getContext(), R.drawable.icon_profile_tabs, "Home")), DiscoverFragment.class, arg1);
Bundle arg2 = new Bundle();
arg2.putInt("Arg for Frag2", 2);
/* if(strtext!=null) {
arg2.putString("user_logid_sectab", strtext);
}*/
tabHost.addTab(tabHost.newTabSpec("Sec").
setIndicator(getTabIndicator(tabHost.getContext(), R.drawable.icon_frnds_tab, "Invite")), ShopFragment.class, arg2);
Bundle arg3 = new Bundle();
arg3.putInt("Arg for Frag3", 3);
/* if(strtext!=null) {
arg3.putString("user_logid_thirdtab", strtext);
}*/
tabHost.addTab(tabHost.newTabSpec("Third").
setIndicator(getTabIndicator(tabHost.getContext(), R.drawable.icon_wish_tab, "Wish")), Thirdtab.class, arg3);
Bundle arg4 = new Bundle();
arg4.putInt("Arg for Frag4", 4);
/*if(strtext!=null) {
arg4.putString("user_logid_fourthtab", strtext);
}*/
tabHost.addTab(tabHost.newTabSpec("Four").
setIndicator(getTabIndicator(tabHost.getContext(), R.drawable.icon_notification_tab, "Alert")), FourthTabs.class, arg4);
return tabHost;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
}
@Override
public void onDetach() {
super.onDetach();
}
public View getTabIndicator(Context context, int icon, String text) {
View view = LayoutInflater.from(context).inflate(R.layout.tab_layout, null);
ImageView iv = (ImageView) view.findViewById(R.id.indicatorImageView);
iv.setImageResource(icon);
TextView txt = (TextView) view.findViewById(R.id.txttb);
txt.setText(text);
return view;
}
}
发现 fragment .java
public class DiscoverFragment extends Fragment {
private Button btn;
public DiscoverFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.discover_frag, container, false);
btn=(Button)rootView.findViewById(R.id.btnhomf);
btn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
WishaFriend ff = new WishaFriend();
android.support.v4.app.FragmentManager fm = getActivity().getSupportFragmentManager();
android.support.v4.app.FragmentTransaction ft = fm.beginTransaction();
fm.popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
// ft.replace(R.id.container_body,ff);
ft.replace(((ViewGroup) getView().getParent()).getId(), ff);
// fm.addToBackStack("sds");
ft.commit();
}
});
return rootView;
}
}
当我运行应用程序时，它显示为第一个屏幕
然后我点击 gotonextfrag 按钮，它会重定向到下一个 fragment ，我得到这个屏幕
现在从这个 fragment 开始，如果我按下设备的后退按钮，我的应用程序就会关闭
xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
style="@style/MyToolBarStyle.Base"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
>
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:adjustViewBounds="true"
android:src="@drawable/toolbartitle"/>
</android.support.v7.widget.Toolbar>
<android.support.v4.widget.DrawerLayout
android:id="@+id/drawerLayout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- activity view -->
<!-- Framelayout to display Fragments -->
<FrameLayout
android:id="@+id/container_body"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<!-- navigation drawer -->
<fragment
android:id="@+id/fragment_navigation_drawer"
android:name="com.balloons.balloonationn.activity.FragmentDrawer"
android:layout_width="@dimen/nav_drawer_width"
android:layout_height="match_parent"
android:layout_gravity="start"
app:layout="@layout/fragment_navigation_drawer"
tools:layout="@layout/fragment_navigation_drawer" />
</android.support.v4.widget.DrawerLayout>
</LinearLayout>
最佳答案
这是Activity的正常行为。当您按下后退按钮时，它会结束当前 Activity 。
关于java - fragment 无法正常工作，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/34670278/