android - ListView Activity 到 ListFragment 与 SQLite DB

Question

我在将我创建的另一个应用程序的工作 ListView 转换为 ListFragment 时遇到问题

我已经摆脱了大部分错误，但仍有一些错误困扰着我。我已经评论了我遇到错误的地方以及它们是什么。

有人可以看看这个并告诉我我缺少什么吗。

谢谢!!!

package com.mycomp.myapp;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import android.app.Dialog;
import android.app.ListActivity;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.support.v4.app.ListFragment;
import android.support.v4.app.LoaderManager;
import android.support.v4.content.CursorLoader;
import android.support.v4.content.Loader;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.View.OnClickListener;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView.AdapterContextMenuInfo;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;

import com.mycomp.myapp.contentprovider.TT_MilageContentProvider;
import com.mycomp.myapp.database.TT_MilageTable;

public class MilageFragment extends ListFragment implements LoaderManager.LoaderCallbacks<Cursor> {

        private static final int ACTIVITY_CREATE = 0;
        private static final int ACTIVITY_EDIT = 1;
        private static final int DELETE_ID = Menu.FIRST + 1;
        private SimpleCursorAdapter adapter;
        private static int dividerHeight = 2; 

        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            fillData();
            registerForContextMenu(getListView());
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {             
                View rootView = inflater.inflate(R.layout.milage, container, false);
                ListView listView = (ListView) rootView.findViewById(R.id.list);
                return rootView;
        }

        public boolean onCreateOptionsMenu(Menu menu) {
            MenuInflater inflater = getActivity().getMenuInflater();
            inflater.inflate(R.menu.main, menu);
            return true;
        }

        @Override
        public boolean onOptionsItemSelected(MenuItem item) {
            switch (item.getItemId()) {
            case R.id.insert:
              createItem();
              return true;
            }
            return super.onOptionsItemSelected(item);
        }

        public boolean onContextItemSelected(MenuItem item, Context context) {
            switch (item.getItemId()) {
            case DELETE_ID:
              AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();
              Uri uri = Uri.parse(TT_MilageContentProvider.CONTENT_URI + "/" + info.id);
              context.getContentResolver().delete(uri, null, null);
              fillData();
              return true;
            }
            return super.onContextItemSelected(item);
        }




        // ***** IT'S TELLING ME TO REMOVE THE ARGUMENTS TO MATCH 'INTENT' ***** 
        //       new Intent(this, MilageDetailActivity.class);

        private void createItem() {
            Intent i = new Intent(this, MilageDetailActivity.class);
            startActivityForResult(i, ACTIVITY_CREATE);
        }






        // ***** IT'S TELLING ME TO REMOVE THE ARGUMENTS TO MATCH 'INTENT' ***** 
        //       new Intent(this, MilageDetailActivity.class);

        @Override
        public void onListItemClick(ListView l, View v, int position, long id) {
            super.onListItemClick(l, v, position, id);
            Intent i = new Intent(this, MilageDetailActivity.class);
            Uri todoUri = Uri.parse(TT_MilageContentProvider.CONTENT_URI + "/" + id);
            i.putExtra(TT_MilageContentProvider.CONTENT_ITEM_TYPE, todoUri);

            startActivityForResult(i, ACTIVITY_EDIT);
        }

        @Override
        public void onActivityResult(int requestCode, int resultCode, Intent intent) {
            super.onActivityResult(requestCode, resultCode, intent);
        }



          //  *******  The Error is.....
          // The constructor SimpleCursorAdapter(MilageFragment, int, null, String[], int[], int) is undefined on
          //    new SimpleCursorAdapter(this, R.layout.milage_row, null, from, to, 0);

        private void fillData() {
            String[] from = new String[] { TT_MilageTable.COLUMN_SUMMARY };
            int[] to = new int[] { R.id.label };

            getLoaderManager().initLoader(0, null, this);
            adapter = new SimpleCursorAdapter(this, R.layout.milage_row, null, from, to, 0);

            setListAdapter(adapter);
          }

        @Override
          public void onCreateContextMenu(ContextMenu menu, View v,
              ContextMenuInfo menuInfo) {
            super.onCreateContextMenu(menu, v, menuInfo);
            menu.add(0, DELETE_ID, 0, R.string.menu_delete);
          }




          //  *******  The Error is.....
          // The constructor CursorLoader(MilageFragment, Uri, String[], null, null, null) is undefined and to 
          // Remove Arguments to match 'CursorLoader(Context)'

        public Loader<Cursor> onCreateLoader(int id, Bundle args) {
            String[] projection = { TT_MilageTable.COLUMN_ID, TT_MilageTable.COLUMN_SUMMARY };
            CursorLoader cursorLoader = new CursorLoader(this, TT_MilageContentProvider.CONTENT_URI, projection, null, null, null);
            return cursorLoader;
        }

        public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
            adapter.swapCursor(data);
        }

        public void onLoaderReset(Loader<Cursor> loader) {
            adapter.swapCursor(null);
        }

        @Override
        public void onDestroy() {
              super.onDestroy();
              android.os.Process.killProcess(android.os.Process.myPid());
          }
        } 

Answer 1

改变

new Intent(this, MilageDetailActivity.class);

到

new Intent(getActivity(), MilageDetailActivity.class);

Intent 需要上下文， fragment 不是从上下文派生的。

关于其他错误的相同问题。用 getActivity() 替换“this”，以便传递正确的上下文。