Java 片段:尝试调用虚拟方法';android.view.view android.view.view.findViewById(int)和#x27;关于空对象引用
我试图插入一个从我的SQLite数据库填充的GridView,但是我得到了错误 “尝试在空对象引用上调用虚拟方法'android.view.view android.view.view.findViewById(int)'” MyAdapter.javaclassJava 片段:尝试调用虚拟方法';android.view.view android.view.view.findViewById(int)和#x27;关于空对象引用,java,android,sqlite,gridview,adapter,Java,Android,Sqlite,Gridview,Adapter,我试图插入一个从我的SQLite数据库填充的GridView,但是我得到了错误 “尝试在空对象引用上调用虚拟方法'android.view.view android.view.view.findViewById(int)'” MyAdapter.javaclass public class MyAdapter extends BaseAdapter { Context context; ArrayList<Players> playerList; private static Lay
public class MyAdapter extends BaseAdapter {
Context context;
ArrayList<Players> playerList;
private static LayoutInflater inflater = null;
public MyAdapter(Context context, ArrayList<Players> playerList){
this.context = context;
this.playerList = playerList;
inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public int getCount() {
return playerList.size();
}
@Override
public Object getItem(int position) {
return position;
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null)
convertView = inflater.inflate(R.layout.layout_grid_item, null);
TextView idTextView = (TextView) convertView.findViewById(R.id.tv_player_id);
TextView nameTextView = (TextView) convertView.findViewById(R.id.tv_player_name);
TextView roleTextView = (TextView) convertView.findViewById(R.id.tv_player_role);
Players p = new Players();
p = playerList.get(position);
idTextView.setText("ID " + String.valueOf(p.getId()));
nameTextView.setText("Name " + String.valueOf(p.getName()));
roleTextView.setText("Role " + String.valueOf(p.getRole()));
return convertView;
}
}
RolesFragment.java
public class RolesFragment extends Fragment {
GridView gridView;
ArrayList<Players> playersList;
MyAdapter adapter;
public View onCreateView(LayoutInflater inflater,ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_viewroles, container, false);
gridView = (GridView) getView().findViewById(R.id.gv_players);
DatabaseHelper databaseHelper = new DatabaseHelper(getActivity());
playersList = new ArrayList<Players>();
playersList = databaseHelper.getPlayers();
adapter = new MyAdapter(getActivity(), playersList);
gridView.setAdapter(adapter);
return view;
}
公共类RolesFragment扩展了片段{
GridView;
ArrayList玩家列表;
MyAdapter适配器;
创建视图上的公共视图(布局、充气机、视图组容器、,
Bundle savedInstanceState){
视图=充气机。充气(R.layout.fragment\u viewroles,container,false);
gridView=(gridView)getView().findViewById(R.id.gv_);
DatabaseHelper DatabaseHelper=新的DatabaseHelper(getActivity());
PlayerList=新的ArrayList();
playersList=databaseHelper.getPlayers();
adapter=新的MyAdapter(getActivity(),playerList);
setAdapter(适配器);
返回视图;
}
}问题是getView()
返回空值
在fragment中,您必须使用:fragment的视图
实例
因此,不是:
gridView = (GridView) getView().findViewById(R.id.gv_players);
使用:
问题是getView()
返回空值
在fragment中,您必须使用:fragment的视图
实例
因此,不是:
gridView = (GridView) getView().findViewById(R.id.gv_players);
使用:
当然!!非常感谢,在玩了几个小时的代码后,它现在可以工作了。@TussRamzan如果答案有效…请将其标记为正确。谢谢你!!非常感谢,在玩了几个小时的代码后,它现在可以工作了。@TussRamzan如果答案有效…请将其标记为正确。谢谢
gridView = (GridView) view.findViewById(R.id.gv_players);