Warning: file_get_contents(/data/phpspider/zhask/data//catemap/5/excel/23.json): failed to open stream: No such file or directory in /data/phpspider/zhask/libs/function.php on line 167

Warning: Invalid argument supplied for foreach() in /data/phpspider/zhask/libs/tag.function.php on line 1116

Notice: Undefined index: in /data/phpspider/zhask/libs/function.php on line 180

Warning: array_chunk() expects parameter 1 to be array, null given in /data/phpspider/zhask/libs/function.php on line 181
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_Java_Android_Sqlite_Gridview_Adapter - Fatal编程技术网

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

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,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

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 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);