android2.3 api demo 学习系列（9）--App/Activity/QuickContactsDemo

现在我们来学习如何使用Content Provider来访问android的contacts数据库。

1、布局配置

 

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:minHeight="48dip"
    android:paddingLeft="0dip"
    android:paddingRight="9dip" >

    <QuickContactBadge
        android:id="@+id/app_activity_quick_contacks_badge"
        style="?android:attr/quickContactBadgeStyleWindowSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginBottom="3dip"
        android:layout_marginLeft="2dip"
        android:layout_marginRight="14dip"
        android:layout_marginTop="4dip" 
        android:src="@drawable/phone"/>
    <TextView
        android:id="@+id/app_activity_quick_contacks_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:layout_toRightOf="@id/app_activity_quick_contacks_badge"
        android:paddingLeft="2dip"
        android:textAppearance="?android:attr/textAppearanceMedium" />

</RelativeLayout>

 

2、代码实现

 

//定义需要的列
	 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);
	     //定义查询条件
	     String select = "((" + Contacts.DISPLAY_NAME + " NOTNULL) AND ("
	             + Contacts.HAS_PHONE_NUMBER + "=1) AND ("
	             + Contacts.DISPLAY_NAME + " != '' ))";
	     //请求需要的数据
	     Cursor c =
	             getContentResolver().query(Contacts.CONTENT_URI, CONTACTS_SUMMARY_PROJECTION, select,
	             null, Contacts.DISPLAY_NAME + " COLLATE LOCALIZED ASC");
	     startManagingCursor(c);//Cursor生命周期交由activity负责管理
	     ContactListItemAdapter adapter = new ContactListItemAdapter(this, R.layout.app_activity_quick_contacts, c);
	     setListAdapter(adapter);
	
	 }

	private final class ContactListItemAdapter extends ResourceCursorAdapter {
		public ContactListItemAdapter(Context context, int layout, Cursor c) {
		    super(context, layout, c);
		}
		
		@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.app_activity_quick_contacks_name);
		    cache.photoView = (QuickContactBadge) view.findViewById(R.id.app_activity_quick_contacks_badge);
		    view.setTag(cache);
		
		    return view;
		}
	}

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

 3、在manifest中添加权限

 

<uses-permission android:name="android.permission.READ_CONTACTS" />
<uses-permission android:name="android.permission.WRITE_CONTACTS" />

 4、效果图：

知识扩展（源自sdk）

Content Provider 为不同应用之间共享数据提供了统一的接口，通过对底层数据源的抽象，Content Provider 实现了应用程序代码和数据层分离。Android 平台对大部分的数据库都提供了对应的Content Provider 接口：

 

1.  Browser： 读取和修改Bookmark，Browser history 或Web Searches。
2.  CallLog： 查看或是更新Call History（打入电话或是打出电话，未接电话等）
3.  Contacts： 检索，修改或存储通讯录。
4.  MediaStore： 访问媒体库（包括声音，视频，图像等）。
5.  Settings： 访问系统设置，查看或是修改蓝牙设置，铃声设置等。

Android 系统的每个Content Provider 都定义了一个CONTENT_URI，功能类似于数据库的名称。Android 中每个Context 对象（如Activity）都含有一个ContentResolver，ContentResolver 可以根据CONTENT_URI 获取对应的Content Provider。

 

具体使用时我们在spplication中获取到 call ContentResolver对象，调用其 ContentResolver.query()方法，该query方法接着调用具体ContentProvider提供者的ContentProvider.query()方法。

 

mCursor = getContentResolver().query(
    UserDictionary.Words.CONTENT_URI,   // The content URI 
    mProjection,                        // 列名
    mSelectionClause                    // 查询条件
    mSelectionArgs,                     // 查询参数
    mSortOrder);                        // 排序

 

 query的参数说明：

 1、读取数据

 

String[] mSelectionArgs = {"test"};
mSelectionClause = UserDictionary.Words.WORD + " = ?";

mCursor = getContentResolver().query(
    UserDictionary.Words.CONTENT_URI, 
    mProjection,                       
    mSelectionClause,                  
    mSelectionArgs,
    mSortOrder); 
//数据显示可以绑定到列表上
String[] mWordListColumns =
{
    UserDictionary.Words.WORD,   // Contract class constant containing the word column name
    UserDictionary.Words.LOCALE  // Contract class constant containing the locale column name
};

// Defines a list of View IDs
int[] mWordListItems = { R.id.dictWord, R.id.locale};

// Creates a new SimpleCursorAdapter
mCursorAdapter = new SimpleCursorAdapter(
    getApplicationContext(),               // The application's Context object
    R.layout.wordlistrow,                  // A layout in XML for one row in the ListView
    mCursor,                               // The result from the query
    mWordListColumns,                      // A string array of column names in the cursor
    mWordListItems,                        // An integer array of view IDs in the row layout
    0);                                    // Flags (usually none are needed)

// Sets the adapter for the ListView
mWordList.setAdapter(mCursorAdapter);

//或者自行处理数据

 

while (mCursor.moveToNext()) {

        // Gets the value from the column.
        newWord = mCursor.getString(index);

        // Insert code here to process the retrieved word.

        ...

        // end of while loop
    }

 

2、插入数据

 

// Defines a new Uri object that receives the result of the insertion
Uri mNewUri;

...

// Defines an object to contain the new values to insert
ContentValues mNewValues = new ContentValues();

/*
 * Sets the values of each column and inserts the word. The arguments to the "put"
 * method are "column name" and "value"
 */
mNewValues.put(UserDictionary.Words.APP_ID, "example.user");
mNewValues.put(UserDictionary.Words.LOCALE, "en_US");
mNewValues.put(UserDictionary.Words.WORD, "insert");
mNewValues.put(UserDictionary.Words.FREQUENCY, "100");

mNewUri = getContentResolver().insert(
    UserDictionary.Word.CONTENT_URI,   // the user dictionary content URI
    mNewValues                          // the values to insert
);

 3、更新数据

 

// Defines an object to contain the updated values
ContentValues mUpdateValues = new ContentValues();

// Defines selection criteria for the rows you want to update
String mSelectionClause = UserDictionary.Words.LOCALE +  "LIKE ?";
String[] mSelectionArgs = {"en_%"};

// Defines a variable to contain the number of updated rows
int mRowsUpdated = 0;

...

/*
 * Sets the updated value and updates the selected words.
 */
mUpdateValues.putNull(UserDictionary.Words.LOCALE);

mRowsUpdated = getContentResolver().update(
    UserDictionary.Words.CONTENT_URI,   // the user dictionary content URI
    mUpdateValues                       // the columns to update
    mSelectionClause                    // the column to select on
    mSelectionArgs                      // the value to compare to
);

 4、删除数据

 

// Defines selection criteria for the rows you want to delete
String mSelectionClause = UserDictionary.Words.APP_ID + " LIKE ?";
String[] mSelectionArgs = {"user"};

// Defines a variable to contain the number of rows deleted
int mRowsDeleted = 0;

...

// Deletes the words that match the selection criteria
mRowsDeleted = getContentResolver().delete(
    UserDictionary.Words.CONTENT_URI,   // the user dictionary content URI
    mSelectionClause                    // the column to select on
    mSelectionArgs                      // the value to compare to
);

 其中关于批量处理的请参看sdk

 

最后需要在manifest中加入需要的权限