Android：从第二个活动刷新游标加载器

时间：2013-08-08 01:06:20

标签： android listview android-activity android-cursorloader

祝你有个美好的一天。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）和下一个代码：

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);
} }

然后，我有管理详细视图的活动，我可以更新或添加项目，名为MarcaDetailActivity：

package com.example.crudapp.activity;

import android.app.Activity;
import android.content.ContentValues;
import android.content.Intent;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;

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

public class MarcaDetailActivity extends Activity {

MarcaCursorAdapter crsAdap;
private Integer idReg;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.detalle_marca);

    Bundle extras = getIntent().getExtras();

    if(extras != null && extras.get("ACTION").equals("EXISTING"))  //Invocamos fillData
        fillData((Uri)extras.get("DET"));
    else
        cleanForm();

}

public void cleanForm() {
    ((Button)findViewById(R.id.todo_edit_button)).setVisibility(View.INVISIBLE);
    ((Button)findViewById(R.id.todo_insert_button)).setVisibility(View.VISIBLE);
}

public void fillData(Uri uri) {
    String[] projection = { MarcaCP.Marca.CODIGO,
            MarcaCP.Marca.CLASIFICACION, MarcaCP.Marca.NOMBRE, MarcaCP.Marca.RANKING};
    //builder.
    Cursor cur = getContentResolver().query(uri, projection, null, null, null);

    if(cur != null) {
        cur.moveToFirst();
        ((EditText)findViewById(R.id.detNombre)).setText(cur.getString(cur.getColumnIndex(MarcaCP.Marca.NOMBRE)));
        ((EditText)findViewById(R.id.detCodigo)).setText(cur.getString(cur.getColumnIndex(MarcaCP.Marca.CODIGO)));
        setIdReg(cur.getInt(cur.getColumnIndex(MarcaCP.Marca.ID)));
        ((EditText)findViewById(R.id.todo_edit_button)).setVisibility(View.VISIBLE);
        ((EditText)findViewById(R.id.todo_insert_button)).setVisibility(View.INVISIBLE);
        String clasif = cur.getString(cur.getColumnIndex(MarcaCP.Marca.CLASIFICACION));
        int rank = cur.getInt(cur.getColumnIndex(MarcaCP.Marca.RANKING));

        Spinner spRnk = ((Spinner)findViewById(R.id.detRanking));
        Spinner spClasf = ((Spinner)findViewById(R.id.detClasificacion));

        //Buscamos setear los spinners en sus valores
        for(short ps = 0; ps < spRnk.getCount(); ps++) {
            String tmpRnk = (String)spRnk.getItemAtPosition(ps);
            if(tmpRnk.equalsIgnoreCase("" + rank))
                spRnk.setSelection(ps);
        }

        //Buscamos setear los spinners en sus valores
        for(short ps = 0; ps < spClasf.getCount(); ps++) {
            String tmpClas = (String)spClasf.getItemAtPosition(ps);
            if(tmpClas.equalsIgnoreCase(clasif))
                spClasf.setSelection(ps);
        }

        cur.close();
    }
}

private boolean validate() {
    boolean res = true;

    return res;
}

public void guardar(View view) {
    if(validate()) {

        ContentValues cv = new ContentValues();
        cv.put(MarcaCP.Marca.CLASIFICACION, (String)((Spinner)findViewById(R.id.detClasificacion)).getSelectedItem() );
        cv.put(MarcaCP.Marca.CODIGO, ((TextView)findViewById(R.id.detCodigo)).getText().toString() );
        cv.put(MarcaCP.Marca.NOMBRE, ((TextView)findViewById(R.id.detNombre)).getText().toString() );
        cv.put(MarcaCP.Marca.RANKING, Integer.parseInt("" + ((Spinner)findViewById(R.id.detRanking)).getSelectedItem() ));

        getContentResolver().insert(MarcaCP.CONTENT_URI, cv);
    }

    Toast.makeText(MarcaDetailActivity.this, "Registro registrado",
            Toast.LENGTH_SHORT).show();
    //Refrescamos el grid y cerramos la actividad
    //((MarcaActivity)this.getCallingActivity()).refrescarLista()
    //getLoaderManager().restartLoader(0, null, MarcaActivity.class);

    this.finish();
}

public void regresar() {
    Intent i = new Intent(MarcaDetailActivity.this, MarcaActivity.class);
    i.putExtra("REFRESH", true);
    startActivity(i);
}

public void actualizar(View view) {
    if(validate()) {
        ContentValues cv = new ContentValues();
        cv.put(MarcaCP.Marca.CLASIFICACION, (String)((Spinner)findViewById(R.id.detClasificacion)).getSelectedItem() );
        cv.put(MarcaCP.Marca.CODIGO, (String)((TextView)findViewById(R.id.detCodigo)).getText() );
        cv.put(MarcaCP.Marca.NOMBRE, (String)((TextView)findViewById(R.id.detNombre)).getText() );
        cv.put(MarcaCP.Marca.ID, getIdReg() );
        cv.put(MarcaCP.Marca.RANKING, Integer.parseInt("" + ((Spinner)findViewById(R.id.detRanking)).getSelectedItem() ));

        getContentResolver().update(MarcaCP.CONTENT_URI, cv, null, null);
    }
}

@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;
}

public Integer getIdReg() {
    return idReg;
}

public void setIdReg(Integer idReg) {
    this.idReg = idReg;
} }

正如您在MarcaDetailActivity的方法保护中所看到的，首先我使用我的自定义内容提供商插入项目，然后我使用Toast显示确认消息，最后完成活动，但是当我这样做时，listview isn＆ ＃39; t通过cursorloader刷新。我在这里阅读（stackoverflow）和其他我必须打电话的页面

getLoaderManager().restartLoader(LIST_ID, null, this);

但在我发现所有内容（在数据库中插入数据并刷新列表）的所有示例都在同一个活动中，但在这种情况下，我有一个列表活动和插入项目的第二个活动，所以我认为我必须从我的详细活动中调用restartLoader，但我不知道如何做到这一点，或者这是否是正确的方法。当我创建调用详细活动的意图并且有一个调用restartLoader的公共方法但我不知道这是否是最佳方法时，我正考虑在附加内容中保存对列表活动的引用。从我的详细活动中刷新光标加载器的最佳方法是什么？

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");
      }
    }*/
  }   }

它已在AndroidManifest.xml中注册：

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

问候。

1 个答案:

答案 0 :(得分：0)

在完成第二项活动之前尝试getContentResolver().notifyChange(MarcaCP.CONTENT_URI, null, false)。

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