android - 访问用户字典android

Question

您好，这是我从用户词典中获取单词的代码。这是我的代码，但我无法运行它...

private String getwordlist() {

        String[] mSelectionArgs={""};


    String[] mProjection ={UserDictionary.Words._ID, UserDictionary.Words.WORD, UserDictionary.Words.FREQUENCY};
    String mSelectionClause = null;

    String mSortOrder = null;

     mCursor = getContentResolver().query(
            UserDictionary.Words.CONTENT_URI,  // The content URI of the words table
            mProjection,                       // The columns to return for each row
            mSelectionClause,                // Either null, or the word the user entered
            mSelectionArgs,                    // Either empty, or the string the user entered
            mSortOrder);                      // The sort order for the returned rows


     if (mCursor.moveToFirst()) {            
            do {             
               String id = mCursor.getString(mCursor.getColumnIndex(UserDictionary.Words._ID));          
               String word = mCursor.getString(mCursor.getColumnIndex(UserDictionary.Words.WORD));
               String freq= mCursor.getString(mCursor.getColumnIndex(UserDictionary.Words.FREQUENCY));
               str=str+" id: "+id+"  word: "+"  frequency: "+freq+"\n";
               System.out.println(str);
            } while(mCursor.moveToNext());
            return str;
     }
     return null;        
}

我遇到了错误

12-06 18:49:58.586: E/AndroidRuntime(17174): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myfirstapp/com.example.myfirstapp.ScrollView}: java.lang.IllegalArgumentException: Cannot bind argument at index 1 because the index is out of range.  The statement has 0 parameters.

这是什么错误..

Answer 1

似乎当 mSelectionClause 为 null 时，mSelectionArgs 也需要为 null。

// If the word is the empty string, gets everything
if (TextUtils.isEmpty(searchWord)) {
    // Setting the selection clause to null will return all words
    mSelectionClause = null;
    mSelectionArgs = null;
} else {
    // Constructs a selection clause that matches the word that the user entered
    mSelectionClause = UserDictionary.Words.WORD + " = ?";
    // Moves the user's input to the selection arguments
    mSelectionArgs = new String[] {searchWord};
}

// Does a query against the table and returns a Cursor object
Cursor cursor = getContentResolver().query(
    UserDictionary.Words.CONTENT_URI, // The content URI of the words table
    mProjection,                      // The columns to return for each row
    mSelectionClause,                 // Either null, or the word the user entered
    mSelectionArgs,                   // Either empty, or the string the user entered
    null);