Android 使用viewPager创建OnActivity后,片段getActivity为null
我有一个带有5个片段的viewpager的TableLayout,我不知道为什么,但在第五个片段中,当我使用getActivity()时,即使在onActivityCreated之后,它也会返回null,而在其他片段中,我在onCreateView中使用它,它工作得很好 我的第五段:Android 使用viewPager创建OnActivity后,片段getActivity为null,android,android-viewpager,android-tablayout,Android,Android Viewpager,Android Tablayout,我有一个带有5个片段的viewpager的TableLayout,我不知道为什么,但在第五个片段中,当我使用getActivity()时,即使在onActivityCreated之后,它也会返回null,而在其他片段中,我在onCreateView中使用它,它工作得很好 我的第五段: public class SettingsFragment extends Fragment { private static final String ARG_SECTION_NUMBER = "sectio
public class SettingsFragment extends Fragment {
private static final String ARG_SECTION_NUMBER = "section_number";
private TextView name,losed_bg,winned_bg,played_bg;
private DatabaseReference mdatabase;
private FirebaseAuth mAuth;
private CircleImageView userpic;
private static final int CAMERA=0,GALLERY=1;
private Typeface font;
private Button logout;
private ProgressBar loading;
private ImageView edit_image;
private EditText edit_text;
private AlertDialog.Builder getImageFrom;
public SettingsFragment() {
}
public static SettingsFragment newInstance(int sectionNumber) {
SettingsFragment fragment = new SettingsFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
mdatabase= FirebaseDatabase.getInstance().getReference().child("USERS").child(mAuth.getCurrentUser().getUid());
mdatabase.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
name.setText(dataSnapshot.child("name").getValue(String.class));
if(dataSnapshot.hasChild("losed")){
//CRASH String spannable = getActivity().getString(R.string.settings_losed)+" "+String.valueOf(dataSnapshot.child("losed").getValue(Integer.class));
losed_bg.setText(spannable);
}
else{
String spannable =getActivity().getString(R.string.settings_losed)+" "+String.valueOf(0);
losed_bg.setText(spannable);
}
if(dataSnapshot.hasChild("winned")){
String spannable = getActivity().getString(R.string.settings_winned)+" "+String.valueOf(dataSnapshot.child("winned").getValue(Integer.class));
winned_bg.setText(spannable);
}
else{
String spannable = getActivity().getString(R.string.settings_winned) + " " + String.valueOf(0);
winned_bg.setText(spannable);
}
if(dataSnapshot.hasChild("played")){
String spannable = getActivity().getString(R.string.settings_played) + " " + String.valueOf(dataSnapshot.child("played").getValue(Integer.class));
played_bg.setText(spannable);
}
else{
String spannable = getActivity().getString(R.string.settings_played) + " " + String.valueOf(0);
played_bg.setText(spannable);
}
if(dataSnapshot.child("profile_pic").getValue(String.class)!=null) {
getImage();
}
else{
loading.setVisibility(View.INVISIBLE);
userpic.setVisibility(View.VISIBLE);
userpic.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
getImageFrom.show();
}
});
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
}
我越来越
java.lang.IllegalStateException: Fragment SettingsFragment{3ee8ade} not attached to Activity
还有我设置表格的活动
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a PlaceholderFragment (defined as a static inner class below).
switch (position){
case 0:
return MainFragment.newInstance(0);
case 1:
return GamesFragment.newInstance(0);
case 2:
return OfflineFragment.newInstance(0);
case 3:
return FactoryFragment.newInstance(0);
case 4:
return SettingsFragment.newInstance(0);
}
return MainFragment.newInstance(position + 1);
}
@Override
public int getCount() {
return 5;
}
@Override
public CharSequence getPageTitle(int position) {
return null;
}
}
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
for (int i = 0; i < tabLayout.getTabCount(); i++) {
switch (i){
case 0:
View view1 = getLayoutInflater().inflate(R.layout.tab_icon_view, null);
view1.findViewById(R.id.icon).setBackgroundResource(R.drawable.ic_home_white_48dp);
tabLayout.getTabAt(i).setCustomView(view1);
break;
case 3:
View view2 = getLayoutInflater().inflate(R.layout.tab_icon_view, null);
view2.findViewById(R.id.icon).setBackgroundResource(R.drawable.factory);
tabLayout.getTabAt(i).setCustomView(view2);
break;
case 1:
View view3 = getLayoutInflater().inflate(R.layout.tab_icon_view, null);
view3.findViewById(R.id.icon).setBackgroundResource(R.drawable.games_icon);
tabLayout.getTabAt(i).setCustomView(view3);
break;
case 2:
View view5 = getLayoutInflater().inflate(R.layout.tab_icon_view, null);
view5.findViewById(R.id.icon).setBackgroundResource(R.drawable.nointernet);
tabLayout.getTabAt(i).setCustomView(view5);
break;
case 4:
View view4 = getLayoutInflater().inflate(R.layout.tab_icon_view, null);
view4.findViewById(R.id.icon).setBackgroundResource(R.drawable.ic_account_circle_white_48dp);
tabLayout.getTabAt(i).setCustomView(view4);
break;
}
}
公共类节SpagerAdapter扩展了FragmentPagerAdapter{
公共部分SpagerAdapter(碎片管理器fm){
超级(fm);
}
@凌驾
公共片段getItem(int位置){
//调用getItem来实例化给定页面的片段。
//返回占位符片段(定义为下面的静态内部类)。
开关(位置){
案例0:
返回MainFragment.newInstance(0);
案例1:
返回GamesFragment.newInstance(0);
案例2:
返回OfflineFragment.newInstance(0);
案例3:
返回FactoryFragment.newInstance(0);
案例4:
返回SettingsFragment.newInstance(0);
}
返回MainFragment.newInstance(位置+1);
}
@凌驾
public int getCount(){
返回5;
}
@凌驾
公共字符序列getPageTitle(int位置){
返回null;
}
}
mSectionsPagerAdapter=newsectionspageradapter(getSupportFragmentManager());
//使用分区适配器设置ViewPager。
mViewPager=(ViewPager)findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
tabLayout=(tabLayout)findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mviewpage);
for(int i=0;i
将用于将侦听器添加到数据库的代码(addValueEventListener
)移动到片段的OnAttach
方法中。根据您使用ViewPager的方式,FragmentPagerAdapter
可能会决定“回收”您的片段。因此,当片段从活动中分离时,删除数据库侦听器非常重要(OnDetach
)
看起来数据库是一个单例数据库,因此侦听器可能会实时显示您的片段甚至活动。可能导致一些内存泄漏。因此,请记住删除侦听器以确定。哪一行导致NPE?第一行使用getActivityChange this-return MainFragment.newInstance(位置+1)获取字符串;返回MainFragment.newInstance(位置);请显示导致错误的确切代码,而不是对其进行描述。请看代码,上面写着ErrorThank的注释,问题是ValueEventListener,我在重写onAttach之前尝试过,但它不起作用,因为我没有将AddListener用于SingleValueEvent。