[英]How to solve “Expression expected” and “cannot infer argument” errors?
誰能幫我解決下面代碼中的“預期表達式”和“無法推斷參數”錯誤? “表達式預期”錯誤發生在public void viewData () {
行中。 雖然線路adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, listItem);
public class profile extends Fragment {
DatabaseHelper dbHelper;
ArrayList<String> listItem;
ArrayAdapter adapter;
ListView userlist;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.activity_profile, container, false);
dbHelper = new DatabaseHelper(getActivity());
userlist = (ListView) v.findViewById(R.id.user_list);
listItem = new ArrayList<>();
dbHelper.viewData();
public void viewData () {
Cursor cursor = dbHelper.viewData();
if (cursor.getCount() == 0) {
Toast.makeText(getActivity(), "No Data Show!", Toast.LENGTH_LONG).show();
} else {
while (cursor.moveToNext()) {
listItem.add(cursor.getString(6));
listItem.add(cursor.getString(0));
listItem.add(cursor.getString(1));
listItem.add(cursor.getString(2));
listItem.add(cursor.getString(3));
listItem.add(cursor.getString(4));
listItem.add(cursor.getString(5));
}
adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, listItem);
userlist.setAdapter(adapter);
}
}
}
這是我在 DatabaseHelper.java 中添加的方法,用於顯示存儲在 SQlite 數據庫中的數據。
public Cursor viewData(){
SQLiteDatabase db = this.getReadableDatabase();
String query = "Select * from "+TABLE_NAME;
Cursor cursor = db.rawQuery(query,null);
return cursor;
}
您不能在另一個方法中擁有一個方法。 但是,您可以自行聲明 ViewData 方法,然后在需要時從 onCreateView 方法調用它。
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