如何实现自动完成与CursorAdapter中 [英] How do I implement autocomplete with cursoradapter

问题描述

我有一个包含2个表4000+行，每行用于自动完成的SQLite数据库。我看到了使用字符串数组来提供自动完成，或他们使用联系人列表做同样非常简单的例子。显然，所有这些工作，在我的情况。我如何用我自己的SQLite数据库用我自己的自动完成数据，自动完成。我一定要创建内容提供商？怎么样？请给我一些例子，因为我找不到任何。我已成功地覆盖 SQLiteOpenHelper 从资产的文件夹中复制数据库备份到/数据/数据​​/ MY_PACKAGE /数据库/文件夹上的机器人。我创建了一个自定义的的CursorAdapter 使用我的自定义 SQLiteOpenHelper 并返回一个光标从 runQueryOnBackgroundThread 。我得到一些_id列缺奇怪的错误。我已经加入了_id列到我的表。我也搞不懂什么是过滤的界面做的，什么时候我的数据得到过滤。我需要什么样的方法/类重写？谢谢你。

I have an SQLite database containing 2 tables 4000+ rows each used for autocomplete. I saw very simple examples that use an array of strings to provide autocomplete or they use the list of contacts to do the same. Obviously none of these work in my case. How do I use my own SQLite database with my own autocomplete data, for the autocomplete. Do I have to create content providers? How? Please give me some examples because I couldn't find any. I have managed to override SQLiteOpenHelper to copy the database from the assets folder to the /data/data/MY_PACKAGE/databases/ folder on the android. I have created a custom CursorAdapter that uses my custom SQLiteOpenHelper and returns a cursor from runQueryOnBackgroundThread. I get strange errors about some _id column missing. I have added the _id column to my tables. I also don't understand what is the Filterable interface doing and when does my data get filtered. What methods/classes do I need to override? Thanks.

推荐答案

它的工作原理。

您需要从这里的SQLiteOpenHelper 。你基本上有你的数据库复制到从你的资产文件夹中的特定文件夹。然后您需要使用您的自定义SQLiteOpenHelper一个自定义的CursorAdapter。

You need the SQLiteOpenHelper from here. You basically have to copy your database into a specific folder from your assets folder. Then you need a custom CursorAdapter that uses your custom SQLiteOpenHelper.

下面是我的活动onCreate方法。

Here is the onCreate method for my activity.

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.search);

        KeywordsCursorAdapter kwadapter = new KeywordsCursorAdapter(this, null);

        txtKeyword = (AutoCompleteTextView)this.findViewById(R.id.txtKeyword);
        txtKeyword.setAdapter(kwadapter);
        txtCity = (AutoCompleteTextView)this.findViewById(R.id.txtCity);
        btnSearch = (Button)this.findViewById(R.id.btnSearch);
        btnSearch.setOnClickListener(this);
    }

下面是CursorAdapter的。施工时，您可以通过空的光标。

Here is the cursoradapter. You can pass null for cursor when constructing.

public class KeywordsCursorAdapter extends CursorAdapter {

    private Context context;

    public KeywordsCursorAdapter(Context context, Cursor c) {
        super(context, c);
        this.context = context;
    }

    //I store the autocomplete text view in a layout xml.
    @Override
    public View newView(Context context, Cursor cursor, ViewGroup parent) {
        LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View v = inflater.inflate(R.layout.keyword_autocomplete, null);
        return v;
    }

    @Override
    public void bindView(View view, Context context, Cursor cursor) {
        String keyword = cursor.getString(cursor.getColumnIndex("keyword"));
        TextView tv = (TextView)view.findViewById(R.id.txtAutocomplete);
        tv.setText(keyword);
    }

    //you need to override this to return the string value when
    //selecting an item from the autocomplete suggestions
    //just do cursor.getstring(whatevercolumn);
    @Override
    public CharSequence convertToString(Cursor cursor) {
        //return super.convertToString(cursor);
        String value = "";
        switch (type) {
        case Keywords:
            value = cursor.getString(DatabaseHelper.KEYWORD_COLUMN);
            break;
        case Cities:
            value = cursor.getString(DatabaseHelper.CITY_COLUMN);
            break;
        }
        return value;
    }

    @Override
    public Cursor runQueryOnBackgroundThread(CharSequence constraint) {
        //return super.runQueryOnBackgroundThread(constraint);
        String filter = "";
        if (constraint == null) filter = "";
        else
            filter = constraint.toString();
                //I have 2 DB-s and the one I use depends on user preference
        SharedPreferences prefs  = PreferenceManager.getDefaultSharedPreferences(context);
        //String selectedCountryCode = prefs.getString("selectedCountry", "GB");
        String selectedCountryCode = prefs.getString(context.getString(R.string.settings_selected_country), "GB");
        selectedCountryCode += "";

                //Here i have a static SQLiteOpenHelper instance that returns a cursor.
        Cursor cursor = MyApplication.getDbHelpers().get(selectedCountryCode.toLowerCase()).getKeywordsCursor(filter);
        return cursor;
    }
}

下面是返回游标的一部分：它只是一个以相同条件选择

Here is the part that returns the cursor: it's just a select with a like condition.

public class DatabaseHelper extends SQLiteOpenHelper {

...

    public synchronized Cursor getKeywordsCursor (String prefix) {
        if (database == null) database = this.getReadableDatabase();
        String[] columns = {"_id", "keyword"};
        String[] args = {prefix};

        Cursor cursor;
        cursor = database.query("keywords", columns, "keyword like '' || ? || '%'", args, null, null, "keyword", "40");

        int idcol = cursor.getColumnIndexOrThrow("_id");
        int kwcol = cursor.getColumnIndexOrThrow("keyword");

        while(cursor.moveToNext()) {
            int id = cursor.getInt(idcol);
            String kw = cursor.getString(kwcol);
            Log.i("keyword", kw);
        }

        cursor.moveToPosition(-1);
        return cursor;
    }

...

}

您还可以创建一个自定义的内容提供商，但在这种情况下，它只是你需要重写另一个无用的类。

You can also create a custom content provider but in this case it would be just another useless class you need to override.

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