Android - 使用 SQLite 的包含 ListView、CursorAdapter 的片段

Question

我有一个包含 listView 和按钮的片段。单击按钮时，将打开一个 DialogFragment，用户可以在其中将数据输入到 EditText 字段中。一旦用户按下setPositiveButton，它就会调用 DBHelper 中的方法将数据插入 SQLite，然后关闭 dialogFragment

我的问题，一旦它关闭 ListView 应该使用列出所有未来输入的新输入进行更新。但是我似乎无法让它工作。我制作了一个 CursorAdapter。有谁知道它为什么不起作用

public class NotesAdapter extends CursorAdapter {

DatabaseHelper help;
private Cursor c;
public NotesAdapter(Context context, Cursor cursor) {
    super(context, cursor, 0);
    c = cursor;
}
@Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
    return LayoutInflater.from(context).inflate(R.layout.list_layout, parent, false);
}

@Override
public void bindView(View view, Context context, Cursor cursor) {

    //View
    TextView title = (TextView) view.findViewById(R.id.item_title);
    TextView body = (TextView) view.findViewById(R.id.item_body);
    TextView date = (TextView) view.findViewById(R.id.item_date);
    //Columns to bound into view
    String getTitle = cursor.getString(cursor.getColumnIndexOrThrow("title"));
    String getBody = cursor.getString(cursor.getColumnIndexOrThrow("body"));
    String getDate = cursor.getString(cursor.getColumnIndexOrThrow("date"));

    title.setText(getTitle);
    body.setText(getBody);
    date.setText(getDate);
}

}

查询数据库表注释，如果sharedpref keyvalue username等于column_creator则返回数据，我的查询对吗？

    public Cursor listNotes() {
    SQLiteDatabase db = help.getReadableDatabase();
    String username = session.getUser();
   // Log.v("Cursor Object", DatabaseUtils.dumpCursorToString(listNotes))
    return db.rawQuery("SELECT * FROM " +help.NOTE_TABLE+ "WHERE " +help.CREATOR+ "= '" + username + "' COLLATE NOCASE", null);

 }

public class Notes extends Fragment {

NotesControl control;
NotesAdapter adapter;
ListView listView;
Button add;
public static boolean isDataUpdated=false;

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_notes, container, false);
    add = (Button) view.findViewById(R.id.addbtn);
    control = new NotesControl(getActivity());
    control.open();
    add.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            NotesDialog dialog = new NotesDialog();
            dialog.show(getChildFragmentManager(), "Dialog Fragment");
        }
    });

    return view;
}

public void onActivityCreate(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
    populateList();
}

最后将 ListView 附加到我的 Fragment，我创建了一个可以调用来填充 List 的方法

    public void populateList(){
      Cursor cursor = control.listNotes();
      listView = (ListView) getView().findViewById(android.R.id.list);
      NotesAdapter adapter = new NotesAdapter(getActivity(), cursor);

      listView.setAdapter(adapter);

    control.close();
}

Answer 1

当您按下确定关闭对话框时，您必须通知光标数据已更改，您必须自行更新..

Edit1：
也将光标声明为该类的数据成员:)
我想让你做如下的事情 实施：

public class Notes extends Fragment {

NotesControl control;
NotesAdapter adapter;
ListView listView;
Button add;
Cursor cursor;
public static boolean isDataUpdated=false;

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_notes, container, false);
    add = (Button) view.findViewById(R.id.addbtn);

    add.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            NotesDialog dialog = new NotesDialog();
            dialog.show(getChildFragmentManager(), "Dialog Fragment");
        }
    });

    return view;
}

public void onActivityCreate(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);

    control = new NotesControl(getActivity());
    control.open();
    populateList();
}

public void populateList(){
      cursor = control.listNotes();
      listView = (ListView) getView().findViewById(android.R.id.list);
      adapter = new NotesAdapter(getActivity(), cursor);

      listView.setAdapter(adapter);

    control.close();
}
@Override
public void onResume(){
    if(isDataUpdated)
   {
     cursor.requery();
     adapter.notifyDataSetChanged();
     Notes.isDataUpdated = false;
    }

}

重要
在您的 DialogFragment Ok 按钮单击事件中添加以下 sn-p

Notes.isDataUpdated = true;

PS：
requery() 方法已被弃用。在掌握下一个逻辑步骤的窍门后，将是用户 CursorLoaders