基于Android的英文词典的实现方法

public class DictionaryAdapter extends CursorAdapter
{
  
}

 private SQLiteDatabase openDatabase()
 {
  try
  {
   // 获得dictionary.db文件的绝对路径
   String databaseFilename = DATABASE_PATH + "/" + DATABASE_FILENAME;
   File dir = new File(DATABASE_PATH);
   // 如果/sdcard/dictionary目录中存在，创建这个目录
   if (!dir.exists())
    dir.mkdir();
   // 如果在/sdcard/dictionary目录中不存在
   // dictionary.db文件，则从res\raw目录中复制这个文件到
   // SD卡的目录（/sdcard/dictionary）
   if (!(new File(databaseFilename)).exists())
   {
    // 获得封装dictionary.db文件的InputStream对象
    InputStream is = getResources().openRawResource(R.raw.dictionary);
    FileOutputStream fos = new FileOutputStream(databaseFilename);
    byte[] buffer = new byte[8192];
    int count = 0;
    // 开始复制dictionary.db文件
    while ((count = is.read(buffer)) > 0)
    {
     fos.write(buffer, 0, count);
    }

    fos.close();
    is.close();
   }
   // 打开/sdcard/dictionary目录中的dictionary.db文件
   SQLiteDatabase database = SQLiteDatabase.openOrCreateDatabase(
     databaseFilename, null);
   return database;
  }
  catch (Exception e)
  {
  }
  return null;
 }

public class Main extends Activity implements OnClickListener, TextWatcher
{
 private final String DATABASE_PATH = android.os.Environment
   .getExternalStorageDirectory().getAbsolutePath()
   + "/dictionary";
 private final String DATABASE_FILENAME = "dictionary.db";
}

public void onClick(View view)
 {
  String sql = "select chinese from t_words where english=?"; 
  Cursor cursor = database.rawQuery(sql, new String[]
  { actvWord.getText().toString() });
  String result = "未找到该单词.";
  // 如果查找单词，显示其中文信息
  if (cursor.getCount() > 0)
  {
   // 必须使用moveToFirst方法将记录指针移动到第1条记录的位置
   cursor.moveToFirst();
   result = cursor.getString(cursor.getColumnIndex("chinese"));
  }
  // 显示查询结果对话框
  new AlertDialog.Builder(this).setTitle("查询结果").setMessage(result)
    .setPositiveButton("关闭", null).show();

 }

 public class DictionaryAdapter extends CursorAdapter
 {
  private LayoutInflater layoutInflater;
  @Override
  public CharSequence convertToString(Cursor cursor)
  {
   return cursor == null ? "" : cursor.getString(cursor
     .getColumnIndex("_id"));
  }
  // 用于将_id字段（也就是english字段）的值设置TextView组件的文本
  // view参数表示用于显示列表项的TextView组件
  private void setView(View view, Cursor cursor)
  {
   TextView tvWordItem = (TextView) view;
 tvWordItem.setText(cursor.getString(cursor.getColumnIndex("_id")));
  }

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

  @Override
  public View newView(Context context, Cursor cursor, ViewGroup parent)
  {
   View view = layoutInflater.inflate(R.layout.word_list_item, null);
   setView(view, cursor);
   return view;
  }
  public DictionaryAdapter(Context context, Cursor c, boolean autoRequery)
  {
   super(context, c, autoRequery);
   // 通过系统服务获得LayoutInflater对象
 
   layoutInflater = (LayoutInflater) context
     .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
  }
 }

 public CharSequence convertToString(Cursor cursor)
 {
   // 如果cursor不为null，返回Cursor对象的地址（cursor.toString（））
  return cursor == null ? "" : cursor.toString();
 }
 

public CharSequence convertToString(Cursor cursor)
{
 return cursor == null ? "" : cursor.getString(cursor
     .getColumnIndex("_id"));
}

public void afterTextChanged(Editable s)
{
  // 必须将english字段的别名设为_id 
  Cursor cursor = database.rawQuery(
    "select english as _id from t_words where english like ?",
    new String[]{ s.toString() + "%" });
  DictionaryAdapter dictionaryAdapter = new DictionaryAdapter(this,cursor, true);
  // actvWord是在Main类中定义的AutoCompleteTextView类型的变量
  actvWord.setAdapter(dictionaryAdapter);
}

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
 android:id="@+id/tvWordItem"
 android:layout_width="fill_parent"
 android:layout_height="wrap_content"
 android:textAppearance="?android:attr/textAppearanceLarge"
 android:gravity="center_vertical"
 android:paddingLeft="6dip"
 android:textColor="#000" 
 android:minHeight="?android:attr/listPreferredItemHeight"
/>