通讯录应用程序-@SuppressWarnings

Question

我正在使用Eclipse ADT构建通讯簿应用程序，并且某些代码有问题。 我收到@SuppressWarnings为SimpleCursorAdapter和deactivate 。

将@SuppressWarnings SuppressWarnings'depresiation'添加到onCreate()

将@SuppressWarnings SuppressWarnings'depresiation'添加到onStop()

我该如何解决？

// AddressBook.java
// Main activity for the Address Book app.
package com.deitel.addressbook;

import android.app.ListActivity;
import android.content.Intent;
import android.database.Cursor;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.CursorAdapter;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;

public class AddressBook extends ListActivity 
{
   public static final String ROW_ID = "row_id"; // Intent extra key
   private ListView contactListView; // the ListActivity's ListView
   private CursorAdapter contactAdapter; // adapter for ListView

   // called when the activity is first created
   @Override
   public void onCreate(Bundle savedInstanceState) >
   {
      super.onCreate(savedInstanceState); // call super's onCreate
      contactListView = getListView(); // get the built-in ListView
      contactListView.setOnItemClickListener(viewContactListener);      

      // map each contact's name to a TextView in the ListView layout
      String[] from = new String[] { "name" }; 
      int[] to = new int[] { R.id.contactTextView }; 
      contactAdapter = new SimpleCursorAdapter(AddressBook.this, R.layout.contact_list_item, null, from, to); 
      setListAdapter(contactAdapter); // set contactView's adapter
   } // end method onCreate

   @Override
   protected void onResume() 
   { 
      super.onResume(); // call super's onResume method

       // create new GetContactsTask and execute it 
       new GetContactsTask().execute((Object[]) null); 
    } // end method onResume

   @Override
   protected void onStop() 
   { 
      Cursor cursor = contactAdapter.getCursor(); // get current Cursor

      if (cursor != null) 
         cursor.deactivate(); // deactivate it

      contactAdapter.changeCursor(null); // adapted now has no Cursor
      super.onStop(); 
   } // end method onStop

   // performs database query outside GUI thread
   private class GetContactsTask extends AsyncTask<Object, Object, Cursor> 
   { 
      DatabaseConnector databaseConnector = 
         new DatabaseConnector(AddressBook.this); 

      // perform the database access
      @Override
      protected Cursor doInBackground(Object... params) 
      { 
         databaseConnector.open(); 

         // get a cursor containing call contacts
         return databaseConnector.getAllContacts(); 
      } // end method doInBackground

      // use the Cursor returned from the doInBackground method
      @Override
      protected void onPostExecute(Cursor result) 
      { 
         contactAdapter.changeCursor(result); // set the adapter's Cursor
         databaseConnector.close(); 
      } // end method onPostExecute
   } // end class GetContactsTask

   // create the Activity's menu from a menu resource XML file
   @Override
   public boolean onCreateOptionsMenu(Menu menu) 
   { 
      super.onCreateOptionsMenu(menu); 
      MenuInflater inflater = getMenuInflater(); 
      inflater.inflate(R.menu.addressbook_menu, menu); 
      return true; 
   } // end method onCreateOptionsMenu

   // handle choice from options menu
   @Override
   public boolean onOptionsItemSelected(MenuItem item) 
   { 
      // create a new Intent to launch the AddEditContact Activity
      Intent addNewContact = 
         new Intent(AddressBook.this, AddEditContact.class); 
      startActivity(addNewContact); // start the AddEditContact Activity
      return super.onOptionsItemSelected(item); // call super's method
   } // end method onOptionsItemSelected

   // event listener that responds to the user touching a contact's name
   // in the ListView
   OnItemClickListener viewContactListener = new OnItemClickListener() 
   { 
      @Override
      public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, 
         long arg3) 
      { 
         // create an Intent to launch the ViewContact Activity
         Intent viewContact = 
            new Intent(AddressBook.this, ViewContact.class); 

         // pass the selected contact's row ID as an extra with the Intent
         viewContact.putExtra(ROW_ID, arg3); 
         startActivity(viewContact); // start the ViewContact Activity
      } // end method onItemClick
   }; // end viewContactListener
} // end class AddressBook

Answer 1

请参阅此SO问题以获取所有提供的日食清单。

并回答您的问题。 您必须在该方法之前添加@SuppressWarnings 。

Java语言规范要求“未检查”和“弃用” ，因此对所有编译器都应有效。

Answer 2

deprecation警告表示您所使用的类，方法或变量已被库的作者标记为不适合将来使用，因此您应避免使用有问题的项。 该文档通常指定问题所在以及使用什么。 例如， SimpleCursorAdapter的文档说 ：

不建议在API级别11中使用此构造方法。不建议使用此选项，因为它会导致在应用程序的UI线程上执行游标查询，从而可能导致响应速度不佳甚至导致应用程序无响应错误。 或者，将LoaderManager与CursorLoader一起使用。

如果存在绝对必须使用不推荐使用的功能的情况，则可以简单地将@SuppressWarnings("deprecation")到带有警告的行中，但应尽可能避免这样做。