如何把AutoCompleteTextView连接到数据库

      AutoCompleteTextView可以根据输入的文字来显示提示, 它的Adapter可以是一个list, 也可以动态的提取数据库数据. 
写了一个例子来展示, 建立一个数据库来储存人名, 只要在AutoCompleteTextView里面输入2个字母就会显示匹配下拉单.
这是一个定制的CursorAdapter, newView会返回一个包含cursor里文字的view, bindView把cursor的数据绑定在view里, convertToString会把view的数据转换为AutoCompleteTextView显示的文字, runQueryOnBackgroundThread方法会查询数据库.

 

private class MyCursorAdpter extends CursorAdapter { private int columnIndex; public MyCursorAdpter(Context context, Cursor c, int col) { super(context, c); this.columnIndex = col; } @Override public View newView(Context context, Cursor cursor, ViewGroup parent) { final LayoutInflater inflater = LayoutInflater.from(context); final TextView view = (TextView) inflater.inflate( android.R.layout.simple_dropdown_item_1line, parent, false); view.setText(cursor.getString(columnIndex)); return view; } @Override public void bindView(View view, Context context, Cursor cursor) { ((TextView) view).setText(cursor.getString(columnIndex)); } @Override public String convertToString(Cursor cursor) { return cursor.getString(columnIndex); } @Override public Cursor runQueryOnBackgroundThread(CharSequence constraint) { if (constraint != null) { String selection = "name like /'" + constraint.toString() +"%/'"; return sqlite.query("test", columns, selection, null, null, null, null); } else { return null; } } } 

 

建立数据库, 以及添加数据, 使用CursorAdapter的数据库必须包含_id项.

private void createDatas() { String createTable = "create table test (name varchar(255), _id varchar(255))"; sqlite.execSQL(createTable); ContentValues values = new ContentValues(); values.put("name", "nicole"); values.put("_id", "0"); sqlite.insert("test", null, values); values.put("name", "nicolas"); values.put("_id", "1"); sqlite.insert("test", null, values); values.put("name", "jean"); values.put("_id", "2"); sqlite.insert("test", null, values); values.put("name", "jennyfer"); values.put("_id", "3"); sqlite.insert("test", null, values); }