AutoCompleteTextView、ContentResolver、Contacts

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.example.android.apis.view;
import com.example.android.apis.R;
import android.app.Activity;
import android.content.ContentResolver;
import android.content.Context;
import android.database.Cursor;
import android.os.Bundle;
import android.provider.Contacts;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AutoCompleteTextView;
import android.widget.CursorAdapter;
import android.widget.Filterable;
import android.widget.TextView;
public class AutoComplete4 extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.autocomplete_4);
        //跨应用取数据
        ContentResolver content = getContentResolver();
        Cursor cursor = content.query(Contacts.People.CONTENT_URI,
                PEOPLE_PROJECTION, null, null, Contacts.People.DEFAULT_SORT_ORDER);
        
        ContactListAdapter adapter = new ContactListAdapter(this, cursor);
        //AutoCompleteTextView 用数据库中查询的Cursor直接设置Adapter.
        AutoCompleteTextView textView = (AutoCompleteTextView)
                findViewById(R.id.edit);
        textView.setAdapter(adapter);
    }
    // XXX compiler bug in javac 1.5.0_07-164, we need to implement Filterable
    // to make compilation work
    public static class ContactListAdapter extends CursorAdapter implements Filterable {
        public ContactListAdapter(Context context, Cursor c) {
            super(context, c);
            mContent = context.getContentResolver();
        }
        //CursorAdapter 
      //  Adapter that exposes data from a Cursor to a ListView widget. 
      //  The Cursor must include a column named "_id" or this class will not work.
       //_id 可定义为primary key autoincrement
        @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(5));
            return view;
        }
        @Override
        public void bindView(View view, Context context, Cursor cursor) {
            ((TextView) view).setText(cursor.getString(5));
        }
        @Override
        public String convertToString(Cursor cursor) {
            return cursor.getString(5);
        }
        @Override
        public Cursor runQueryOnBackgroundThread(CharSequence constraint) {
            if (getFilterQueryProvider() != null) {
                return getFilterQueryProvider().runQuery(constraint);
            }
//后台查询
            StringBuilder buffer = null;
            String[] args = null;
            if (constraint != null) {
                buffer = new StringBuilder();
                buffer.append("UPPER(");
                buffer.append(Contacts.ContactMethods.NAME);
                buffer.append(") GLOB ?");
                args = new String[] { constraint.toString().toUpperCase() + "*" };
            }
            return mContent.query(Contacts.People.CONTENT_URI, PEOPLE_PROJECTION,
                    buffer == null ? null : buffer.toString(), args,
                    Contacts.People.DEFAULT_SORT_ORDER);
        }
        private ContentResolver mContent;        
    }
//定义要获取的联系人表的列
    private static final String[] PEOPLE_PROJECTION = new String[] {
        Contacts.People._ID,
        Contacts.People.PRIMARY_PHONE_ID,
        Contacts.People.TYPE,
        Contacts.People.NUMBER,
        Contacts.People.LABEL,
        Contacts.People.NAME,
    };
}

<AutoCompleteTextView android:id="@+id/edit"
android:completionThreshold="1"
android:completionHint="@string/autocomplete_5_hint"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>

android:completionHint="@string/autocomplete_5_hint" 自动填充后，最底下的提示信息。

比如： <string name="autocomplete_5_hint">Typing * will show all of your contacts.</string>

android:completionThreshold="1" 输入多于一个字符才会自动填充