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：
- Browser： 读取和修改Bookmark，Browser history 或Web Searches。
- CallLog： 查看或是更新Call History（打入电话或是打出电话，未接电话等）
- Contacts： 检索，修改或存储通讯录。
- MediaStore： 访问媒体库（包括声音，视频，图像等）。
- 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