Api demo源码学习（8）--App/Activity/QuickContactsDemo --获取系统联系人信息

本节通过Content Provider机制获取系统中的联系人信息，注意这个Anctivity直接继承的是ListActivity，所以不再需要setContentView函数来加载布局文件了（我自己新建一个项目来跑这个anctivity时在这里卡了半天）。

在AndroidManifest.xml中需配置权限，以访问手机中的联系人信息，添加如下代码：
[align=left]<uses-permission android:name="android.permission.READ_CONTACTS"></uses-permission>[/align]

具体解释放入代码中。

public class QuickContactsDemo extends ListActivity {

//设置要从联系人数据库中要查找的数据
static final String[] CONTACTS_SUMMARY_PROJECTION = new String[] {
Contacts._ID, // 0
Contacts.DISPLAY_NAME, // 1
Contacts.STARRED, // 2
Contacts.TIMES_CONTACTED, // 3
Contacts.CONTACT_PRESENCE, // 4
Contacts.PHOTO_ID, // 5
Contacts.LOOKUP_KEY, // 6
Contacts.HAS_PHONE_NUMBER, // 7
};

static final int SUMMARY_ID_COLUMN_INDEX = 0;
static final int SUMMARY_NAME_COLUMN_INDEX = 1;
static final int SUMMARY_STARRED_COLUMN_INDEX = 2;
static final int SUMMARY_TIMES_CONTACTED_COLUMN_INDEX = 3;
static final int SUMMARY_PRESENCE_STATUS_COLUMN_INDEX = 4;
static final int SUMMARY_PHOTO_ID_COLUMN_INDEX = 5;
static final int SUMMARY_LOOKUP_KEY = 6;
static final int SUMMARY_HAS_PHONE_COLUMN_INDEX = 7;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

//设置通过uri要查询的语句
String select = "((" + Contacts.DISPLAY_NAME + " NOTNULL) AND ("
+ Contacts.HAS_PHONE_NUMBER + "=1) AND ("
+ Contacts.DISPLAY_NAME + " != '' ))";

//通过ContentResolver的query函数，传入联系人的URI ：Contacts.CONTENT_URI查询所需信息，最后一个参数决定按照联系人的姓名进行降序排列
Cursor c =
getContentResolver().query(Contacts.CONTENT_URI, CONTACTS_SUMMARY_PROJECTION, select,
null, Contacts.DISPLAY_NAME + " COLLATE LOCALIZED ASC");

//一个cursor使用完毕后需将其关闭，cursor.close()。如果不想自己管理cursor，
//可调用下面的startManagingCursor语句让系统自行管理，cursor会在程序结束时自动释放
startManagingCursor(c);

ContactListItemAdapter adapter = new ContactListItemAdapter(this, R.layout.quick_contacts, c);
setListAdapter(adapter);

}

private final class ContactListItemAdapter extends ResourceCursorAdapter {
public ContactListItemAdapter(Context context, int layout, Cursor c) {
super(context, layout, c);
}

//重写bindView方法，设置每个ListView内每一个view的值
@Override
public void bindView(View view, Context context, Cursor cursor) {
final ContactListItemCache cache = (ContactListItemCache) view.getTag();
TextView nameView = cache.nameView;
QuickContactBadge photoView = cache.photoView;
// Set the name
cursor.copyStringToBuffer(SUMMARY_NAME_COLUMN_INDEX, cache.nameBuffer);
int size = cache.nameBuffer.sizeCopied;
cache.nameView.setText(cache.nameBuffer.data, 0, size);
final long contactId = cursor.getLong(SUMMARY_ID_COLUMN_INDEX);
final String lookupKey = cursor.getString(SUMMARY_LOOKUP_KEY);
cache.photoView.assignContactUri(Contacts.getLookupUri(contactId, lookupKey));
}

@Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
View view = super.newView(context, cursor, parent);
ContactListItemCache cache = new ContactListItemCache();
cache.nameView = (TextView) view.findViewById(R.id.name);
cache.photoView = (QuickContactBadge) view.findViewById(R.id.badge);
view.setTag(cache);

return view;
}
}

final static class ContactListItemCache {
public TextView nameView;
public QuickContactBadge photoView;
public CharArrayBuffer nameBuffer = new CharArrayBuffer(128);
}
}

quick_contacts.xml布局文件：

<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:paddingLeft="0dip"
android:paddingRight="9dip"
android:layout_height= "wrap_content"
android:minHeight="48dip">

<QuickContactBadge
android:id="@+id/badge"
android:layout_marginLeft="2dip"
android:layout_marginRight="14dip"
android:layout_marginTop="4dip"
android:layout_marginBottom="3dip"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_height= "wrap_content"
android:layout_width= "wrap_content"
android:src="@drawable/ic_contact_picture"
style="?android:attr/quickContactBadgeStyleWindowSmall" />

<TextView
android:id="@+id/name"
android:textAppearance="?android:attr/textAppearanceMedium"
android:paddingLeft="2dip"
android:layout_centerVertical="true"
android:layout_toRightOf="@id/badge"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />

</RelativeLayout>

[align=left]以上即可。[/align]
[align=left]
[/align]
[align=left]下一节：Api demo源码学习（9）--App/Activity/Receive Result --Activity间传递数据[/align]