用例:我在 Activity 上有一个 Fragment，它在 Splash 后立即启动。我的 Fragment 由 ViewPager 组成，它在 ViewPager TabLayout 上显示一些值。如果我第一次运行它，一切都会正常；但如果我从设备上的后台删除该应用程序并再次运行它，则 ViewPager 选项卡详细信息上的文本不会显示。
代码
Fragment 在 splash 之后调用，由 ViewPager -
public class SlidingTab extends Fragment {
private static final String TAG = "TabLayout";
private static String POSITION = "POSITION";
private Context context;
private AppCompatActivity activity;
private FragmentActivity fragmentContext;
// private Toolbar toolbar;
private TextView badge;
private ViewPager viewPager;
private TabLayout slidingTab;
private BroadcastReceiver mMyBroadcastReceiver;
private SearchView searchview;
// private LinearLayout bellLayout , accountInfoLayout;
private Boolean flag = false;
android.widget.PopupWindow changeStatusPopUp;
Point point;
// private SearchView searchview;
private Toolbar toolbar;
private LinearLayout maplistview, listView;
private PreferenceforApp myprefs;
private PageAdapter adapter;
private Bundle bundle;
public SlidingTab() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.sliding_tab, container, false);
initialise(v);
initialiseListeners();
bundle = getArguments();
return v;
}
private void initialiseListeners() {
}
private void initialise(View v) {
context = getActivity();
myprefs = new PreferenceforApp(context);
activity = (AppCompatActivity) getActivity();
viewPager = (ViewPager) v.findViewById(R.id.view_pager);
viewPager.setOffscreenPageLimit(2);
adapter = new PageAdapter(getChildFragmentManager(), context);
viewPager.setAdapter(adapter);
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
final InputMethodManager imm = (InputMethodManager) getActivity().getSystemService(
Context.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(viewPager.getWindowToken(), 0);
// adapter.set_current_position(1,2,3);
// adapter.notifyDataSetChanged();
if (bundle != null && bundle.size() != 0) {
if ((!bundle.getString("viewpager").equalsIgnoreCase("submit")) &&
(!bundle.getString("viewpager").equalsIgnoreCase("inProgress"))) {
slidingTab.getTabAt(0).setText("New (" + SingleTon.getInstance().getNewjob() + ")");
slidingTab.getTabAt(1).setText("In Progress (" + SingleTon.getInstance().getInprogressjob() + ")");
slidingTab.getTabAt(2).setText("Completed (" + SingleTon.getInstance().getCompletedjob() + ")");
}
bundle.clear();
} else {
slidingTab.getTabAt(0).setText("New (" + SingleTon.getInstance().getNewjob() + ")");
slidingTab.getTabAt(1).setText("In Progress (" + SingleTon.getInstance().getInprogressjob() + ")");
slidingTab.getTabAt(2).setText("Completed (" + SingleTon.getInstance().getCompletedjob() + ")");
}
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
slidingTab = (TabLayout) v.findViewById(R.id.sliding_tabs);
badge = (TextView) v.findViewById(R.id.badge);
badge.setVisibility(View.GONE);
final RelativeLayout bellLayout = (RelativeLayout) v.findViewById(R.id.bell_linearlayout1);
final RelativeLayout accountInfoLayout = (RelativeLayout) v.findViewById(R.id.account_linearlayout1);
if (myprefs.getCounter() != 0) {
badge.setVisibility(View.VISIBLE);
}
toolbar = (Toolbar) v.findViewById(R.id.toolbar1);
maplistview = (LinearLayout) v.findViewById(R.id.maplist);
listView = (LinearLayout) v.findViewById(R.id.list_linearlayout);
activity = (AppCompatActivity) getActivity();
searchview = (SearchView) v.findViewById(R.id.searchView);
searchview.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
searchview.setIconified(false);
}
});
LinearLayout logout_Layout = (LinearLayout) layout.findViewById(R.id.logoutlayout);
logout_Layout.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
popup.dismiss();
FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
FragmentTransaction ft = getActivity().getSupportFragmentManager().beginTransaction();
fragmentManager.popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
myprefs.setUserState(LoginActivity
.setLoginState(Constant.userStateLoggedOut));
Log.i("logged out", myprefs.getUserState());
myprefs.setIsLogIn(false);
Intent myIntent = new Intent(getActivity(), LoginActivity.class);
myIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP
| Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(myIntent);
}
});
}
@Override
public void onStart() {
super.onStart();
if (activity.getSupportActionBar() != null) {
if (activity.getSupportActionBar().isShowing()) {
activity.getSupportActionBar().hide();
}
}
}
@Override
public void onStop() {
super.onStop();
if (activity.getSupportActionBar() != null) {
if (!activity.getSupportActionBar().isShowing()) {
activity.getSupportActionBar().show();
}
}
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
if (outState != null) {
outState.putInt(POSITION, slidingTab.getSelectedTabPosition());
}
}
@Override
public void onActivityCreated(Bundle savedInstaceState) {
super.onActivityCreated(savedInstaceState);
Log.d(TAG, "onActivityCreated Called");
}
@Override
public void onResume() {
super.onResume();
LocationManager locationManager = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
if (bundle != null) {
if (bundle.containsKey("viewpager")) {
if (bundle.getString("viewpager").equalsIgnoreCase("submit")) {
viewPager.setCurrentItem(2, false);
} else if (bundle.getString("viewpager").equalsIgnoreCase("inProgress")) {
viewPager.setCurrentItem(1, false);
}
}
}
mMyBroadcastReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
// Here you can refresh your listview or other UI
badge.setVisibility(View.VISIBLE);
}
};
try {
LocalBroadcastManager.getInstance(context).registerReceiver(mMyBroadcastReceiver,
new IntentFilter("com.parse.push.intent.RECEIVE"));
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
if (locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {
// Toast.makeText(getActivity(), "GPS is Enabled on your device", Toast.LENGTH_SHORT).show();
} else {
Utils.showGPSDisabledAlertToUser(getContext());
}
}
@Override
public void onPause() {
// TODO Auto-generated method stub
super.onPause();
LocalBroadcastManager.getInstance(context).unregisterReceiver(mMyBroadcastReceiver);
}
}
在上面的代码中，这些行用于设置 ViewPager 选项卡文本。起初，这被调用，但从后台删除应用程序并重新启动后，在我选择其中一个选项卡之前不会显示任何数据。
slidingTab.getTabAt(0).setText("New ("+ SingleTon.getInstance().getNewjob()+")");
slidingTab.getTabAt(1).setText("In Progress ("+ SingleTon.getInstance().getInprogressjob()+")");
slidingTab.getTabAt(2).setText("Completed ("+ SingleTon.getInstance().getCompletedjob()+")");
}
});
}
SlidingTab.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/frame_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/white"
android:orientation="vertical"
tools:context="com.RareMediaCompany.BDTrial.SlidingTab">
<include
android:id="@+id/toolbar1"
layout="@layout/toolbar_job"/>
<com.RareMediaCompany.BDTrial.Utils.CustomTabLayout
android:id="@+id/sliding_tabs"
style="@style/CustomTabLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#eeeeee"
app:tabIndicatorColor="#f39220"
app:tabIndicatorHeight="3dp"
app:tabMaxWidth="0dp"
app:tabMode="fixed"
app:tabPaddingEnd="0dp"
app:tabPaddingStart="0dp"
app:tabSelectedTextColor="#808080"
app:tabTextAppearance="@android:style/TextAppearance.Widget.TabWidget"/>
<LinearLayout
android:id="@+id/linear1"
android:layout_width="match_parent"
android:layout_height="70dp"
android:layout_marginLeft="5dp"
android:layout_marginRight="8dp"
android:background="@android:color/white"
android:orientation="horizontal"
android:weightSum="1">
<android.support.v7.widget.SearchView
android:id="@+id/searchView"
style="@style/CitySearchView"
android:layout_width="300dp"
android:layout_height="45dp"
android:layout_gravity="center"
android:layout_marginEnd="5dp"
android:layout_marginLeft="5dp"
android:layout_weight="1"
android:background="@drawable/searchview"
android:clickable="true"/>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:orientation="horizontal"
android:weightSum="1">
<LinearLayout
android:id="@+id/list_linearlayout"
android:layout_width="45dp"
android:layout_height="45dp"
android:layout_gravity="center"
android:layout_weight="0.5"
android:background="#f39220">
<!--android:background="#75aadb">-->
<ImageView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="2dp"
android:layout_weight="0.3"
android:src="@drawable/listicon"/>
</LinearLayout>
<LinearLayout
android:id="@+id/maplist"
android:layout_width="45dp"
android:layout_height="45dp"
android:layout_gravity="center"
android:layout_weight="0.5"
android:background="#75aadb">
<ImageView
android:layout_width="20dp"
android:layout_height="wrap_content"
android:layout_marginRight="3dp"
android:layout_marginTop="2dp"
android:layout_weight="0.3"
android:src="@drawable/map_icon_1"/>
</LinearLayout>
</LinearLayout>
</LinearLayout>
<!--android:layout_width="320dp"-->
<!--android:layout_height="wrap_content"-->
<!--android:layout_marginLeft="10dp"-->
<!--android:layout_marginTop="10dp"-->
<!--android:id="@+id/searchview"/>-->
<android.support.v4.view.ViewPager
android:id="@+id/view_pager"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="@android:color/white"/>
</LinearLayout>
MainActivity.java(保存 fragment 的 Activity)
private static MainActivity mainActivityRunningInstance;
public static MainActivity getInstance() {
return mainActivityRunningInstance;
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mainActivityRunningInstance = this;
Fabric.with(this, new Crashlytics());
overridePendingTransition(R.anim.grow_from_middle, R.anim.shrink_to_middle);
setContentView(R.layout.activity_main);
contentFragment = NavigationDrawerFragment.newInstance(R.drawable.content_music);
drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
drawerLayout.setScrimColor(Color.TRANSPARENT);
linearLayout = (LinearLayout) findViewById(R.id.left_drawer);
linearLayout.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
drawerLayout.closeDrawers();
}
});
myPref = new PreferenceforApp(MainActivity.this);
fragmentManager = getSupportFragmentManager();
setActionBar(title);
// createMenuList();
viewAnimator = new ViewAnimator<>(this, list, contentFragment, drawerLayout, this);
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.setCustomAnimations(R.anim.glide_fragment_horizontal_in, R.anim.glide_fragment_horizontal_out);
ft.replace(R.id.content_frame1, new SlidingTab(), "recycler");
ft.addToBackStack("recycler");
ft.commit();
}
图片
在应用程序首次启动时:
从后台删除后重新运行:
Could someone point out what the error is or suggest a different approach.
ViewPager代码
public class PageAdapter extends FragmentStatePagerAdapter {
private static final String TAG = "PageAdapter";
public int newjob, inprogressjob, completedjob;
final int PAGE_COUNT = 3;
Fragment fragment;
private String tabTitles[] = new String[]{"New", "In Progress", "Completed"};
private Context context;
HashMap<Integer,Fragment> map = new HashMap<>();
public PageAdapter(FragmentManager fm, Context context) {
super(fm);
this.context = context;
}
@Override
public Fragment getItem(int position) {
Log.d(TAG, "New Instance Created :" + position);
switch (position) {
case 0:
fragment = new JobFragment();
map.put(position,fragment);
return fragment;
case 1:
fragment=new InProgressJobFragment();
map.put(position,fragment);
return fragment;
case 2:
fragment = new CompletedJobFragment();
map.put(position,fragment);
return fragment;
}
return null;
}
public Fragment getFragment(int key) {
return map.get(key);
}
public void set_current_position(int newjob, int inprogress, int completedjob) {
this.newjob = newjob;
this.inprogressjob = inprogress;
this.completedjob = completedjob;
notifyDataSetChanged();
}
// @Override
// public CharSequence getPageTitle(int position) {
// return tabTitles[position];
// }
@Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0: return "New" + " (" + SingleTon.getInstance().getNewjob() + ")";
case 1: return "In Progress" + " (" + SingleTon.getInstance().getInprogressjob() + ")";
case 2: return "Completed" + " (" + SingleTon.getInstance().getCompletedjob() + ")";
}
return "";
}
@Override
public int getCount() {
return PAGE_COUNT;
}
private String getFragmentTag(int viewPagerId, int fragmentPosition)
{
return "android:switcher:" + viewPagerId + ":" + fragmentPosition;
}
}
最佳答案
我认为问题是由主线程引起的
使用下面的代码 希望它能解决您的问题
slidingTab.postDelayed(new Runnable() {
@Override
public void run() {
slidingTab.setupWithViewPager(viewPager);
slidingTab.getTabAt(0).setText("New ("+ SingleTon.getInstance().getNewjob()+")");
slidingTab.getTabAt(1).setText("In Progress ("+ SingleTon.getInstance().getInprogressjob()+")");
slidingTab.getTabAt(2).setText("Completed ("+ SingleTon.getInstance().getCompletedjob()+")");
}
},2500);
}
关于android - Viewpager 和 Fragment 问题，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/37944008/