问题描述
我正在尝试将数据从适配器类发送到具有TabLayout
的Activity类。但是我得到NullPointerException
。我搜索了一些答案,但使用了一个答案,但对我却不起作用。
以下是代码
适配器类
@Override
public void onBindViewHolder(@NonNull ViewHolder holder,int position) {
final Player player = playerList.get(position);
holder.playerName.setText(player.getPlayerName());
Picasso.get().load(player.getProfilePhoto()).placeholder(R.drawable.ic_default_pic)
.into(holder.playerImage);
holder.itemView.setonClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(mContext,PlayerProfile.class);
intent.putExtra("playerId",player.getPlayerID());
intent.putExtra("team",player.getPlaysFor());
mContext.startActivity(intent);
}
});
}
具有TabLayout的活动类
public class PlayerProfile extends AppCompatActivity {
public String playerId,team;
TabLayout tabLayout;
ViewPager viewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_player_profile);
tabLayout = findViewById(R.id.tabLayout);
viewPager = findViewById(R.id.viewPager);
Intent intent = getIntent();
playerId = intent.getStringExtra("playerId");
team = intent.getStringExtra("team");
ViewPageAdapter viewPageAdapter = new ViewPageAdapter(getSupportFragmentManager());
viewPageAdapter.addFragment(new PlayerInfo(),"Player Info");
viewPageAdapter.addFragment(new CurrentStats(),"Current Stats");
viewPageAdapter.addFragment(new WholeIPL(),"Whole Stats");
Bundle bundle = new Bundle();
bundle.putString("playerId",playerId);
bundle.putString("team",team);
PlayerInfo info = new PlayerInfo();
CurrentStats stats = new CurrentStats();
WholeIPL ipl = new WholeIPL();
info.setArguments(bundle);
stats.setArguments(bundle);
ipl.setArguments(bundle);
viewPager.setAdapter(viewPageAdapter);
tabLayout.setupWithViewPager(viewPager);
}
static class ViewPageAdapter extends FragmentPagerAdapter {
private ArrayList<Fragment> fragments;
private ArrayList<String> titles;
ViewPageAdapter(@NonNull FragmentManager fm) {
super(fm);
this.fragments = new ArrayList<>();
this.titles = new ArrayList<>();
}
@NonNull
@Override
public Fragment getItem(int position) {
return fragments.get(position);
}
@Override
public int getCount() {
return fragments.size();
}
void addFragment(Fragment fragment,String title) {
fragments.add(fragment);
titles.add(title);
}
@Nullable
@Override
public CharSequence getPageTitle(int position) {
return titles.get(position);
}
}
TabLayout片段
public class PlayerInfo extends Fragment {
String playerID,team;
TextView name,dob,batting,bowling,jersey;
CircleImageView circleImageView;
DatabaseReference databaseReference;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater,@Nullable ViewGroup container,@Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_player_info,container,false);
Bundle bundle = this.getArguments();
assert bundle != null;
playerID = bundle.getString("playerId");
team = bundle.getString("team");
Log.d(TAG,"onCreateView: " + playerID);
}
它在Log
语句中显示为null。因此,关于如何将playerId
传递给Fragment的任何建议?
解决方法
您首先要传递新的片段,然后定义新的片段并在其上使用setArguments,并且不使用它们。 具体看一下以下代码行:
ViewPageAdapter viewPageAdapter = new ViewPageAdapter(getSupportFragmentManager());
viewPageAdapter.addFragment(new PlayerInfo(),"Player Info");
viewPageAdapter.addFragment(new CurrentStats(),"Current Stats");
viewPageAdapter.addFragment(new WholeIPL(),"Whole Stats");
在这里,您正在将新的片段传递到addFragment以及此处:
Bundle bundle = new Bundle();
bundle.putString("playerId",playerId);
bundle.putString("team",team);
PlayerInfo info = new PlayerInfo();
CurrentStats stats = new CurrentStats();
WholeIPL ipl = new WholeIPL();
info.setArguments(bundle);
stats.setArguments(bundle);
ipl.setArguments(bundle);
viewPager.setAdapter(viewPageAdapter);
tabLayout.setupWithViewPager(viewPager);
您正在创建片段的新实例并在其上使用setArguments,新片段以后将不再使用。 考虑将适配器定义和addFragments移到setArguments下,并使用定义的片段。
,Bundle bundle = new Bundle();
bundle.putString("playerId",team);
PlayerInfo info = new PlayerInfo();
CurrentStats stats = new CurrentStats();
WholeIPL ipl = new WholeIPL();
info.setArguments(bundle);
stats.setArguments(bundle);
ipl.setArguments(bundle);
Above code is required for creating instances for fragment and setting value to them.
You need to use these instances of fragment to the ViewPagerAdapter (As shown)
ViewPageAdapter viewPageAdapter = new ViewPageAdapter(getSupportFragmentManager());
viewPageAdapter.addFragment(info,"Player Info");
viewPageAdapter.addFragment(stats,"Current Stats");
viewPageAdapter.addFragment(ipl,"Whole Stats");
**And then set the viewpageradapter**
viewPager.setAdapter(viewPageAdapter);
tabLayout.setupWithViewPager(viewPager);
您正在创建片段的新实例,并在其上使用setArguments,而这些实例从未使用过。