怎样获取android手机联系人并按字母展示(一）

android提供了本地数据库的查询uri,能够查询出数据:

採用一个AsyncQueryHandler来进行查询, AsyncQueryHandler自己开启了线程来进行数据查询，非常方便

protected AsyncQueryHandler mQueryHandler;

protected final void queryPersonal() {
		mQueryHandler.startQuery(QUERY_TOKEN, null, ContactsContract.Contacts.CONTENT_URI, 
				Personal.CONTACTS_SUMMARY_PROJECTION, null, null, getSortOrder(ContactsContract.Contacts.DISPLAY_NAME));
	}

	
	protected static String getSortOrder(String fieldName) {
		//substr为截取函数。取第一个字母
		//COLLATE主要用于对字符进行排
		//COLLATE LOCALIZED 按本地语言进行排序
		return "CASE WHEN substr(UPPER(" + fieldName + "), 1, 1) BETWEEN 'A' AND 'Z' THEN 1 else 10 END," +
				fieldName + " COLLATE LOCALIZED ASC";
	}

protected final class MyHandler extends AsyncQueryHandler { 
		/**
		 * Asynchronous query handler constructor.
		 */
		public MyHandler(Context context) {
			super(context.getContentResolver());
		}
		
		/**
		 * On query completion.
		 */
		@Override
		<strong>protected void onQueryComplete(int token, Object cookie, Cursor cursor) </strong>{ //handler查询完的回调
			if (cursor == null || cursor.isClosed()) {
				return;
			}
			if (!isFinishing()) {
				setLoading(false);
				if (mAdapter != null) {
					mAdapter.setLoading(false);
					mAdapter.changeCursor(cursor);
				} 
				
				if (cursor.getCount() == 0) {
					mEmtytext.setVisibility(View.VISIBLE);
				} else {
					mEmtytext.setVisibility(View.INVISIBLE);
				}
			} else {
				if (cursor != null && !cursor.isClosed()) {
					cursor.close();
				}
			}
		}
	}

<?xml version="1.0" encoding="utf-8"?
>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:rcm="http://schemas.android.com/apk/res/com.ringcentral.android"
    android:id="@+id/contact_list_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/bgColorMain"
    android:orientation="vertical">


    <ListView
        android:id="@android:id/list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:cacheColorHint="@android:color/transparent"
        android:descendantFocusability="afterDescendants"
        android:divider="@null"
        android:fastScrollEnabled="true"
        android:listSelector="@drawable/bg_list_item_selector" />

    <RelativeLayout
        android:id="@+id/no_contact_indication"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <TextView
            android:id="@+id/emptyListText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:singleLine="true"
            android:text="No Contacts"
            android:textColor="@color/text_no_items"
            android:textSize="20sp" />

        <ProgressBar
            android:id="@+id/loading"
            style="@style/RCMProgressBar"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:visibility="gone" />
    </RelativeLayout>

</LinearLayout>

	protected static final class SectionedContactListItemCache {
		public TextView sectionHeader;
		public TextView nameView;
		public TextView typeView;
		public ImageView photoView;
		public ImageView detailItemIcon;
        <span style="white-space:pre">	</span>public View nameTypeWrapper;
	}
	
	
	protected final class ContactsAdapter extends ResourceCursorAdapter  {


		
		public ContactsAdapter(Context context) {
			super(context, R.layout.contacts_list_item_photo,null);
		}

		
		@Override
		public void changeCursor(Cursor c) {
			super.changeCursor(c);
		}
		
		protected String getTitle(String displayName) {
			String title;
			/** check if the first letter is English letter */
			Matcher matcher = mPattern.matcher(displayName);
			if (!matcher.find()) {
				title = NONE_ENGLISH_LETTER_TITLE;
			} else {
				title = displayName.trim().substring(0, 1).toUpperCase(Locale.US);
			}
			return title;
		}
		
		protected String getDisplayName(Cursor c) {
			
			String displayName =  c.getString(Personal.NAME_COLUMN_INDEX);
					
			if(TextUtils.isEmpty(displayName)) {
				return "";
			}
			
			return displayName;
		}
		


		@Override
		public void bindView(View view, Context context, Cursor cursor) {
			final SectionedContactListItemCache cache = (SectionedContactListItemCache) view.getTag();
			cache.typeView.setVisibility(View.GONE);
			cache.photoView.setVisibility(View.VISIBLE);
			String name = cursor.getString(Personal.NAME_COLUMN_INDEX);
			if (TextUtils.isEmpty(name)) {
				cache.nameView.setText(R.string.contact_no_name);
			} else {
				cache.nameView.setText(name);
			}
		}
		
		
		@Override
		public View newView(Context context, Cursor cursor, ViewGroup parent) {
			
			View view = super.newView(context, cursor, parent);
			final SectionedContactListItemCache cache = new SectionedContactListItemCache();
            cache.nameTypeWrapper = view.findViewById(R.id.name_type);
			cache.sectionHeader = (TextView) view.findViewById(R.id.txtSectionHeader);
			cache.nameView = (TextView) view.findViewById(R.id.name);
			cache.typeView = (TextView) view.findViewById(R.id.type);
			cache.photoView = (ImageView) view.findViewById(R.id.photo);
			cache.detailItemIcon = (ImageView) view.findViewById(R.id.contacts_detail_item_icon);
			view.setTag(cache);
			
			return view;
		}
		
		
	}//end of adapter

<?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="wrap_content"
    android:orientation="vertical">

    <TextView
        android:id="@+id/txtSectionHeader"
        android:layout_width="match_parent"
        android:layout_height="@dimen/list_item_section_height"
        android:background="@drawable/bg_contacts_section_header"
        android:gravity="center_vertical|left"
        android:paddingLeft="@dimen/default_padding_to_side"
        android:textColor="@color/contacts_text_separator_text_color"
        android:textSize="@dimen/font_size_medium" />

    <RelativeLayout
        android:id="@+id/contact_item"
        android:layout_width="match_parent"
        android:layout_height="@dimen/general_list_view_item_height">

        <ImageView
            android:id="@+id/photo"
            android:layout_width="@dimen/favorites_item_picture_width"
            android:layout_height="match_parent"
            android:layout_alignParentLeft="true"
            android:layout_alignWithParentIfMissing="true"
            android:paddingTop="6dp"
            android:paddingBottom="6dp"
            android:layout_marginLeft="@dimen/contact_photo_margin_left_right"
            android:scaleType="fitCenter"
            />

        <!-- this icon may be added in next version, and now it would be hidden -->

        <ImageView
            android:id="@+id/contacts_detail_item_icon"
            android:layout_width="50dip"
            android:layout_height="60dip"
            android:layout_alignParentRight="true"
            android:layout_marginRight="0dip"
            android:cropToPadding="true"
            android:duplicateParentState="false"
            android:paddingBottom="3dip"
            android:paddingTop="3dip"
            android:scaleType="fitCenter"
            android:src="@drawable/ic_list_link"
            android:visibility="gone" />

        <RelativeLayout
            android:id="@+id/name_type"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_alignWithParentIfMissing="true"
            android:layout_toLeftOf="@id/contacts_detail_item_icon"
            android:layout_marginLeft="@dimen/contact_photo_margin_left_right"
            android:layout_toRightOf="@id/photo"
            android:background="@drawable/bg_list_item_divider">

            <TextView
                android:id="@+id/type"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_alignBaseline="@+id/name"
                android:layout_alignParentRight="true"
                android:layout_marginRight="@dimen/contact_type_margin_left_right"
                android:ellipsize="marquee"
                android:gravity="center_vertical|right"
                android:singleLine="true"
                android:textColor="@color/refresh_control_text_color"
                android:textSize="@dimen/font_size_small" />

            <TextView
                android:id="@+id/name"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_centerVertical="true"
                android:layout_marginRight="@dimen/contact_name_margin_left_right"
                android:layout_toLeftOf="@id/type"
                android:ellipsize="marquee"
                android:gravity="center_vertical|left"
                android:singleLine="true"
                android:textColor="@color/text_color_main"
                android:textSize="@dimen/font_size_medium" />
        </RelativeLayout>
    </RelativeLayout>

</LinearLayout>