Android：从第二个活动刷新游标加载程序

祝你今天愉快。我正在学习Android开发，所以我正在创建一个简单的CRUD应用程序，现在我的主要活动是listview（MarcaActivity），下面是代码：

package com.example.crudapp.activity;

import android.app.Activity;
import android.app.LoaderManager;
import android.content.CursorLoader;
import android.content.Intent;
import android.content.Loader;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;

import com.example.crudapp.MarcaCursorAdapter;
import com.example.crudapp.R;
import com.example.crudapp.cp.MarcaCP;

public class MarcaActivity extends Activity implements
    LoaderManager.LoaderCallbacks<Cursor> {

MarcaCursorAdapter crsAdap;
ListView lstMarcas;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_marca);

    lstMarcas = (ListView)findViewById(R.id.lstMarcas);
    lstMarcas.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
            Intent i = new Intent(MarcaActivity.this, MarcaDetailActivity.class);
            Uri todoUri = Uri.parse(MarcaCP.CONTENT_URI + "/" + arg3);
            i.putExtra("DET", todoUri);
            i.putExtra("ACTION", "EXISTING");

            startActivity(i);
        }

    });
    getLoaderManager().initLoader(0, null, this);

    fillData();
}

protected void onRestoreInstanceState(Bundle savedInstanceState) {
    getLoaderManager().restartLoader(0, null, this);
}

@Override
  public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    case R.id.insertMnu:
        Intent i = new Intent(this, MarcaDetailActivity.class);
        i.putExtra("ACTION", "NEW");
        startActivityForResult(i, 0);
        return true;
    }
    return super.onOptionsItemSelected(item);
  }

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

private void fillData() {
    crsAdap = new MarcaCursorAdapter(this, R.layout.template_marcas, null , 
            new String[]{MarcaCP.Marca.NOMBRE, MarcaCP.Marca.RANKING}, new int[]{R.id.nomMarca, R.id.rankMarca});

    lstMarcas.setAdapter(crsAdap);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.marca, menu);
    return true;
}

@Override
public Loader<Cursor> onCreateLoader(int arg0, Bundle arg1) {
    return new CursorLoader(this, MarcaCP.CONTENT_URI,
            new String[]{MarcaCP.Marca.ID, MarcaCP.Marca.NOMBRE, MarcaCP.Marca.CODIGO, MarcaCP.Marca.RANKING}, null, null, null);
}

@Override
public void onLoadFinished(Loader<Cursor> arg0, Cursor arg1) {
    crsAdap.swapCursor(arg1);
}

@Override
public void onLoaderReset(Loader<Cursor> arg0) {
    crsAdap.swapCursor(null);
} }

但在所有示例中，我发现所有内容（在数据库中插入数据并刷新列表）都在同一个活动中，但在本例中，我有一个带有列表的活动和第二个插入项目的活动，因此我认为我必须从我的详细活动调用restartLoader，但我不知道怎么做，也不知道这样做是否正确。当我创建调用细节活动的意图，并有一个调用restartLoader的公共方法时，我正在考虑将对列表活动的引用保存在extras中，但我不知道这是否是最好的方法。从“我的详细信息”活动中刷新光标加载程序的最佳方法是什么

还有我的内容提供商MarcaCP：

package com.example.crudapp.cp;

import android.content.ContentProvider;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteQueryBuilder;
import android.net.Uri;
import android.text.TextUtils;

import com.example.crudapp.util.ConnHandler;

public class MarcaCP extends ContentProvider {

private static final int TODOS = 10;
private static final int TODO_ID = 20;

public static final Uri CONTENT_URI = Uri.parse("content://provider.marcacp/marcas");
private static final UriMatcher sURIMatcher = new UriMatcher(UriMatcher.NO_MATCH);

static {
    sURIMatcher.addURI("provider.marcacp", "marcas", TODOS);
    sURIMatcher.addURI("provider.marcacp", "marcas" + "/#", TODO_ID);
}

public static class Marca {
    public static final String TABLA = "MARCA";
    public static final String ID = "_id";
    public static final String CODIGO = "codigo";
    public static final String NOMBRE = "nombre";
    public static final String CLASIFICACION = "clasificacion";
    public static final String RANKING = "ranking";
}

private ConnHandler conn;
SQLiteDatabase dbObj;

@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
    int uriType = sURIMatcher.match(uri);
    int rowsDeleted = 0;
    switch (uriType) {
    case TODOS:
      rowsDeleted = dbObj.delete(Marca.TABLA, selection, selectionArgs);
      break;
    case TODO_ID:
      String id = uri.getLastPathSegment();
      if (TextUtils.isEmpty(selection)) {
        rowsDeleted = dbObj.delete(Marca.TABLA,
            Marca.ID + " = " + id, 
            null);
      } else {
        rowsDeleted = dbObj.delete(Marca.TABLA,
           Marca.ID + " =" + id 
            + " and " + selection,
            selectionArgs);
      }
      break;
    default:
      throw new IllegalArgumentException("Unknown URI: " + uri);
    }
    getContext().getContentResolver().notifyChange(uri, null);
    return rowsDeleted;
}

@Override
public String getType(Uri uri) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public Uri insert(Uri uri, ContentValues values) {
    int uriType = sURIMatcher.match(uri);

    long id = 0;
    switch (uriType) {
    case TODOS:
      id = dbObj.insert(Marca.TABLA, null, values);
      break;
    default:
      throw new IllegalArgumentException("Unknown URI: " + uri);
    }
    getContext().getContentResolver().notifyChange(uri, null);
    return Uri.parse("marca/" + id);
}

@Override
public boolean onCreate() {
    conn = new ConnHandler(getContext());
    dbObj = conn.getDb();
    return true;
}

@Override
public Cursor query(Uri uri, String[] projection, String selection,
        String[] selectionArgs, String sortOrder) {
    // Uisng SQLiteQueryBuilder instead of query() method
    SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
    checkColumns(projection);
    queryBuilder.setTables(Marca.TABLA);

    int uriType = sURIMatcher.match(uri);

    switch (uriType) {
    case TODOS:
      break;
    case TODO_ID:
        // Digamos para ver el detalle de un registro
        queryBuilder.appendWhere(Marca.ID + " = "
            + uri.getLastPathSegment());
        break;
      default:
        throw new IllegalArgumentException("Unknown URIx: " + uri);
      }


    Cursor cur = queryBuilder.query(dbObj, projection, selection,
                    selectionArgs, null, null, sortOrder);
    return cur;
}

@Override
public int update(Uri uri, ContentValues values, String selection,
        String[] selectionArgs) {
    int uriType = sURIMatcher.match(uri);
    int rowsUpdated = 0;
    switch (uriType) {
    case TODOS:
      rowsUpdated = dbObj.update(Marca.TABLA, 
          values, 
          selection,
          selectionArgs);
      break;
    case TODO_ID:
      String id = uri.getLastPathSegment();
      if (TextUtils.isEmpty(selection)) {
        rowsUpdated = dbObj.update(Marca.TABLA, 
            values,
            Marca.ID + " =" + id, 
            null);
      } else {
        rowsUpdated = dbObj.update(Marca.TABLA, 
            values,
            Marca.ID + " =" + id 
            + " and " 
            + selection,
            selectionArgs);
      }
      break;
    default:
      throw new IllegalArgumentException("Unknown URI: " + uri);
    }
    getContext().getContentResolver().notifyChange(uri, null);
    return rowsUpdated;
}

private void checkColumns(String[] projection) {
    /*String[] available = { TodoTable.COLUMN_CATEGORY,
        TodoTable.COLUMN_SUMMARY, TodoTable.COLUMN_DESCRIPTION,
        TodoTable.COLUMN_ID };
    if (projection != null) {
      HashSet<String> requestedColumns = new HashSet<String>(Arrays.asList(projection));
      HashSet<String> availableColumns = new HashSet<String>(Arrays.asList(available));
      // Check if all columns which are requested are available
      if (!availableColumns.containsAll(requestedColumns)) {
        throw new IllegalArgumentException("Unknown columns in projection");
      }
    }*/
  }   }

package com.example.crudapp.cp；
导入android.content.ContentProvider；
导入android.content.ContentValues；
导入android.content.UriMatcher；
导入android.database.Cursor；
导入android.database.sqlite.SQLiteDatabase；
导入android.database.sqlite.SQLiteQueryBuilder；
导入android.net.Uri；
导入android.text.TextUtils；
导入com.example.crudapp.util.ConnHandler；
公共类MarcaCP扩展了ContentProvider{
专用静态最终int TODOS=10；
私有静态最终int TODO_ID=20；
公共静态最终Uri内容\u Uri=Uri.parse（“content://provider.marcacp/marcas");
私有静态最终UriMatcher sURIMatcher=新UriMatcher（UriMatcher.NO_匹配）；
静止的{
addURI（“provider.marcacp”、“marcas”、“TODOS”）；
addURI（“provider.marcacp”，“marcas”+“/#”，TODO_ID）；
}
公共静态类Marca{
公共静态最终字符串TABLA=“MARCA”；
公共静态最终字符串ID=“\u ID”；
公共静态最终字符串CODIGO=“CODIGO”；
公共静态最终字符串NOMBRE=“NOMBRE”；
公共静态最终字符串CLASIFICACION=“CLASIFICACION”；
公共静态最终字符串RANKING=“RANKING”；
}
私人康涅狄格州；
sqlitedbobj数据库；
@凌驾
public int delete（Uri、字符串选择、字符串[]selectionArgs）{
int-uriType=sURIMatcher.match（uri）；
int rowsDeleted=0；
开关（URI型）{
待办事项：
rowsDeleted=dbObj.delete（Marca.TABLA，selection，selectionArgs）；
打破
待办案件编号：
String id=uri.getLastPathSegment（）；
if（TextUtils.isEmpty（选择））{
rowsDeleted=dbObj.delete（Marca.TABLA，
Marca.ID+“=”+ID，
无效）；
}否则{
rowsDeleted=dbObj.delete（Marca.TABLA，
Marca.ID+“=”+ID
+"及"选择,，
选择；
}
打破
违约：
抛出新的IllegalArgumentException（“未知URI:+URI”）；
}
getContext（）.getContentResolver（）.notifyChange（uri，null）；
返回删除的行；
}
@凌驾
公共字符串getType（Uri）{
//TODO自动生成的方法存根
返回null；
}
@凌驾
公共Uri插入（Uri、ContentValues）{
int-uriType=sURIMatcher.match（uri）；
长id=0；
开关（URI型）{
待办事项：
id=dbObj.insert（Marca.TABLA，null，value）；
打破
违约：
抛出新的IllegalArgumentException（“未知URI:+URI”）；
}
getContext（）.getContentResolver（）.notifyChange（uri，null）；
返回Uri.parse（“marca/”+id）；
}
@凌驾
公共布尔onCreate（）{
conn=新的ConnHandler（getContext（））；
dbObj=conn.getDb（）；
返回true；
}
@凌驾
公共游标查询（Uri、字符串[]投影、字符串选择、，
字符串[]selectionArgs，字符串排序器）{
//使用SQLiteQueryBuilder代替query（）方法
SQLiteQueryBuilder queryBuilder=newsqlitequerybuilder（）；
检查列（投影）；
queryBuilder.setTables（Marca.TABLA）；
int-uriType=sURIMatcher.match（uri）；
开关（URI型）{
待办事项：
打破
待办案件编号：
//登记册上的数字图书馆
queryBuilder.appendWhere（Marca.ID+“=”
+getLastPathSegment（））；
打破
违约：
抛出新的IllegalArgumentException（“未知URIx:+uri”）；
}
Cursor cur=queryBuilder.query（dbObj、投影、选择、，
selectionArgs、null、null、sortOrder）；
返回电流；
}
@凌驾
公共int更新（Uri、ContentValues、字符串选择、，
字符串[]selectionArgs）{
int-uriType=sURIMatcher.match（uri）；
int rowsUpdated=0；
开关（URI型）{
待办事项：
rowsUpdated=dbObj.update（Marca.TABLA，
价值观
选择，
选择；
打破
待办案件编号：
String id=uri.getLastPathSegment（）；
if（TextUtils.isEmpty（选择））{
rowsUpdated=dbObj.update（Marca.TABLA，
价值观
Marca.ID+“=”+ID，
无效）；
}否则{
rowsUpdated=dbObj.update（Marca.TABLA，
价值观
Marca.ID+“=”+ID
+“和”
+选择，
选择；
}
打破
违约：
抛出新的IllegalArgumentException（“未知URI:+URI”）；
}
getContext（）.getContentResolver（）.notifyChange（uri，null）；
返回原始数据；
}
私有void检查列（字符串[]投影）{
/*String[]available={TodoTable.COLUMN_CATEGORY，
TodoTable.COLUMN\u摘要，TodoTable.COLUMN\u说明，
TodoTable.COLUMN_ID}；
if（投影！=null）{
HashSet requestedColumns=新的HashSet（Arrays.asList（projection））；
HashSet availableColumns=新的HashSet（Arrays.asList（available））；
//检查请求的所有列是否都可用
如果（！availableColumns.containsAll（requestedColumns））{
抛出新的IllegalArgumentException（“投影中的未知列”）；
getLoaderManager().restartLoader(LIST_ID, null, this);

package com.example.crudapp.cp;

import android.content.ContentProvider;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteQueryBuilder;
import android.net.Uri;
import android.text.TextUtils;

import com.example.crudapp.util.ConnHandler;

public class MarcaCP extends ContentProvider {

private static final int TODOS = 10;
private static final int TODO_ID = 20;

public static final Uri CONTENT_URI = Uri.parse("content://provider.marcacp/marcas");
private static final UriMatcher sURIMatcher = new UriMatcher(UriMatcher.NO_MATCH);

static {
    sURIMatcher.addURI("provider.marcacp", "marcas", TODOS);
    sURIMatcher.addURI("provider.marcacp", "marcas" + "/#", TODO_ID);
}

public static class Marca {
    public static final String TABLA = "MARCA";
    public static final String ID = "_id";
    public static final String CODIGO = "codigo";
    public static final String NOMBRE = "nombre";
    public static final String CLASIFICACION = "clasificacion";
    public static final String RANKING = "ranking";
}

private ConnHandler conn;
SQLiteDatabase dbObj;

@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
    int uriType = sURIMatcher.match(uri);
    int rowsDeleted = 0;
    switch (uriType) {
    case TODOS:
      rowsDeleted = dbObj.delete(Marca.TABLA, selection, selectionArgs);
      break;
    case TODO_ID:
      String id = uri.getLastPathSegment();
      if (TextUtils.isEmpty(selection)) {
        rowsDeleted = dbObj.delete(Marca.TABLA,
            Marca.ID + " = " + id, 
            null);
      } else {
        rowsDeleted = dbObj.delete(Marca.TABLA,
           Marca.ID + " =" + id 
            + " and " + selection,
            selectionArgs);
      }
      break;
    default:
      throw new IllegalArgumentException("Unknown URI: " + uri);
    }
    getContext().getContentResolver().notifyChange(uri, null);
    return rowsDeleted;
}

@Override
public String getType(Uri uri) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public Uri insert(Uri uri, ContentValues values) {
    int uriType = sURIMatcher.match(uri);

    long id = 0;
    switch (uriType) {
    case TODOS:
      id = dbObj.insert(Marca.TABLA, null, values);
      break;
    default:
      throw new IllegalArgumentException("Unknown URI: " + uri);
    }
    getContext().getContentResolver().notifyChange(uri, null);
    return Uri.parse("marca/" + id);
}

@Override
public boolean onCreate() {
    conn = new ConnHandler(getContext());
    dbObj = conn.getDb();
    return true;
}

@Override
public Cursor query(Uri uri, String[] projection, String selection,
        String[] selectionArgs, String sortOrder) {
    // Uisng SQLiteQueryBuilder instead of query() method
    SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
    checkColumns(projection);
    queryBuilder.setTables(Marca.TABLA);

    int uriType = sURIMatcher.match(uri);

    switch (uriType) {
    case TODOS:
      break;
    case TODO_ID:
        // Digamos para ver el detalle de un registro
        queryBuilder.appendWhere(Marca.ID + " = "
            + uri.getLastPathSegment());
        break;
      default:
        throw new IllegalArgumentException("Unknown URIx: " + uri);
      }


    Cursor cur = queryBuilder.query(dbObj, projection, selection,
                    selectionArgs, null, null, sortOrder);
    return cur;
}

@Override
public int update(Uri uri, ContentValues values, String selection,
        String[] selectionArgs) {
    int uriType = sURIMatcher.match(uri);
    int rowsUpdated = 0;
    switch (uriType) {
    case TODOS:
      rowsUpdated = dbObj.update(Marca.TABLA, 
          values, 
          selection,
          selectionArgs);
      break;
    case TODO_ID:
      String id = uri.getLastPathSegment();
      if (TextUtils.isEmpty(selection)) {
        rowsUpdated = dbObj.update(Marca.TABLA, 
            values,
            Marca.ID + " =" + id, 
            null);
      } else {
        rowsUpdated = dbObj.update(Marca.TABLA, 
            values,
            Marca.ID + " =" + id 
            + " and " 
            + selection,
            selectionArgs);
      }
      break;
    default:
      throw new IllegalArgumentException("Unknown URI: " + uri);
    }
    getContext().getContentResolver().notifyChange(uri, null);
    return rowsUpdated;
}

private void checkColumns(String[] projection) {
    /*String[] available = { TodoTable.COLUMN_CATEGORY,
        TodoTable.COLUMN_SUMMARY, TodoTable.COLUMN_DESCRIPTION,
        TodoTable.COLUMN_ID };
    if (projection != null) {
      HashSet<String> requestedColumns = new HashSet<String>(Arrays.asList(projection));
      HashSet<String> availableColumns = new HashSet<String>(Arrays.asList(available));
      // Check if all columns which are requested are available
      if (!availableColumns.containsAll(requestedColumns)) {
        throw new IllegalArgumentException("Unknown columns in projection");
      }
    }*/
  }   }

<provider android:name=".cp.MarcaCP" android:authorities="provider.marcacp" />