Android uses CursorLoader to read mobile phone address book

Use CursorLoader to read mobile phone address book

今天get到一个新技能，使用CursorLoader异步加载数据通讯录数据。

实现功能：通过读取手机通讯录所有联系人的名字及联系号码，将数据通过CursorLoader异步加载到ListView上。

This is the rendering. Because I only saved one contact on the emulator, the use effect is not obvious. I downloaded the apk to the phone and installed it to read the contact. There is no problem because the contact is related to some indescribable secrets, so I will not take a screenshot .

Project directory structure diagram:

Very simple, there are only one class and two layout files, one is the activity layout file, and the other is the custom adapter layout file. Okay, it's a custom adapter again. My principle is to write more and practice more when I study, so how come I get complicated.

Code on ——————————————

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.app.LoaderManager;
import android.app.LoaderManager.LoaderCallbacks;
import android.content.CursorLoader;
import android.content.Loader;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;

public class MainActivity extends Activity implements LoaderCallbacks<Cursor> {
    private ListView listView;
    private LoaderManager loaderManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView = (ListView) findViewById(R.id.listView1);
        loaderManager = getLoaderManager();
        loaderManager.initLoader(1111, null, this);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public Loader<Cursor> onCreateLoader(int id, Bundle args) {
        // TODO Auto-generated method stub
        Uri uri = ContactsContract.Contacts.CONTENT_URI;
        CursorLoader cursorLoader = new CursorLoader(this, uri, null, null,
                null, null);
        return cursorLoader;
    }

    @Override
    public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
        // TODO Auto-generated method stub
        List<List<String>> list = new ArrayList<List<String>>();
        //list存储整个联系人的数据
        while (data.moveToNext()) {
            String name = null;
            List<String> list_data = new ArrayList<String>();
            //list_data存储单个联系人的数据，我只读取了名字和电话号码。
            name = data.getString(data
                    .getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME));
            int id = data.getInt(data
            //android 内部通讯录并不是将电话和联系人存储在同一张表格中，而是通过一个ID将联系人和电话关联
                    .getColumnIndex(ContactsContract.Contacts._ID));
            Cursor cursor = getContentResolver().query( //通过ID获取对应的电话表格游标
                    ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
                    null,
                    ContactsContract.CommonDataKinds.Phone.CONTACT_ID + "="
                            + id, null, null);
            while (cursor.moveToNext()) {//遍历游标获取电话

                    list_data.add(name);
                    list_data.add(cursor
                            .getString(cursor
                                    .getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER)));
                                    //ContactsContract.CommonDataKinds下的常量可以去查找一下官方API太多了一两句解释不清，官网这一节有中文的的翻译

            }

            list.add(list_data);
        }
        myAdapter adapter = new myAdapter(list);
        listView.setAdapter(adapter);
    }
//自定义适配器
    class myAdapter extends BaseAdapter {
        List<List<String>> list = new ArrayList<List<String>>();

        public myAdapter(List<List<String>> list) {
            // TODO Auto-generated constructor stub
            this.list = list;
        }

        @Override
        public int getCount() {
            // TODO Auto-generated method stub
            return list.size();
        }

        @Override
        public Object getItem(int position) {
            // TODO Auto-generated method stub
            return list.get(position);
        }

        @Override
        public long getItemId(int position) {
            // TODO Auto-generated method stub
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            // TODO Auto-generated method stub
            View view = null;
            if (convertView == null) {
                view = LayoutInflater.from(MainActivity.this).inflate(
                        R.layout.list, null);

            } else {
                view = convertView;
            }
            TextView textView2 = (TextView) view
                    .findViewById(R.id.list_textView2);
            TextView textView3 = (TextView) view
                    .findViewById(R.id.list_textView3);
            List<String> list1 = new ArrayList<String>();
            list1 = list.get(position);
            textView2.setText(list1.get(0));
            textView3.setText(list1.get(1));
            return view;

        }
    }

    @Override
    public void onLoaderReset(Loader<Cursor> loader) {
        // TODO Auto-generated method stub

    }

}

Layout file:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="#cccccc"
        android:paddingBottom="10sp" >

        <TextView
            android:id="@+id/textView2"
            android:layout_width="0sp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:gravity="center_horizontal"
            android:paddingTop="10dp"
            android:text="姓名"
            android:textColor="#2828ff"
            android:textSize="20sp" />

        <TextView
            android:id="@+id/textView3"
            android:layout_width="0sp"
            android:layout_height="wrap_content"
            android:layout_weight="2"
            android:gravity="center_horizontal"
            android:paddingTop="10dp"
            android:text="电话"
            android:textColor="#2828ff"
            android:textSize="20sp" />
    </LinearLayout>

    <ListView
        android:id="@+id/listView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
    </ListView>

</LinearLayout>

list.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center_vertical|center_horizontal" >
        <TextView
            android:id="@+id/list_textView2"
            android:layout_width="0sp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:gravity="center"
            android:text="TextView"
            android:textSize="20sp" />

        <TextView
            android:id="@+id/list_textView3"
            android:layout_width="0sp"
            android:layout_height="wrap_content"
            android:layout_weight="2"
            android:gravity="center"
            android:text="TextView"
            android:textSize="20sp" />
    </LinearLayout>

</LinearLayout>