Android中ContentProvider和ContentResolver使用入门
<span style="border-collapse: separate; color: #000000; font-family: 'Times New Roman'; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-indent: 0px; white-space: normal; font-size: medium;" class="Apple-style-span"><span style="color: #4b4b4b; font-family: Verdana,Geneva,Arial,Helvetica,sans-serif; font-size: 13px; line-height: 19px;" class="Apple-style-span">在Android中，我们的应用有的时候需要对外提供数据接口，可以有如下几种方法：1）AIDL 2）Broadcast 3）ContentProvider。使用AIDL需要我们编写AIDL接口以及实现，而且对方也要有相应的接口描述，有点麻烦；使用Broadcast，我们不需要任何接口描述，只要协议文档就可以了，但是有点不好就是，这种方式不直接而且是异步的；使用ContentProvider我们不需要接口描述，只需要知道协议，同时这种方式是同步的，使用方便。下面是ContentProvider实现：
<div style="border: 1px solid #cccccc; padding: 4px 5px 4px 4px; background-color: #eeeeee; width: 1006px; font-size: 13px;">http://www.agoit.com/Images/OutliningIndicators/ExpandedBlockStart.gif/**
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif *
http://www.agoit.com/Images/OutliningIndicators/ExpandedBlockEnd.gif */
http://www.agoit.com/Images/OutliningIndicators/None.gifpackage com.backgroundservice;
http://www.agoit.com/Images/OutliningIndicators/None.gif
http://www.agoit.com/Images/OutliningIndicators/None.gifimport android.content.ContentProvider;
http://www.agoit.com/Images/OutliningIndicators/None.gifimport android.content.ContentValues;
http://www.agoit.com/Images/OutliningIndicators/None.gifimport android.content.UriMatcher;
http://www.agoit.com/Images/OutliningIndicators/None.gifimport android.database.Cursor;
http://www.agoit.com/Images/OutliningIndicators/None.gifimport android.database.sqlite.SQLiteDatabase;
http://www.agoit.com/Images/OutliningIndicators/None.gifimport android.database.sqlite.SQLiteQueryBuilder;
http://www.agoit.com/Images/OutliningIndicators/None.gifimport android.net.Uri;
http://www.agoit.com/Images/OutliningIndicators/None.gifimport android.util.Log;
http://www.agoit.com/Images/OutliningIndicators/None.gif
http://www.agoit.com/Images/OutliningIndicators/ExpandedBlockStart.gif/**
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * TODO
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif *
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * @author tianlu
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * @version 1.0 Create At : 2010-2-18 下午01:58:39
http://www.agoit.com/Images/OutliningIndicators/ExpandedBlockEnd.gif */
http://www.agoit.com/Images/OutliningIndicators/ExpandedBlockStart.gifpublic class TestContentProvider extends ContentProvider {
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif private SQLiteDatabase mDb;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif private DatabaseHelper mDbHelper = null;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif private static final String DATABASE_NAME = "rssitems.db";
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif private static final String DATABASE_TABLE_NAME = "rssItems";
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif private static final int DB_VERSION = 1;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif private static final int ALL_MESSAGES = 1;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif private static final int SPECIFIC_MESSAGE = 2;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // Set up our URL matchers to help us determine what an
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // incoming URI parameter is.
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif private static final UriMatcher URI_MATCHER;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif static {
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif URI_MATCHER = new UriMatcher(UriMatcher.NO_MATCH);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif URI_MATCHER.addURI("test", "item", ALL_MESSAGES);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif URI_MATCHER.addURI("test", "item/#", SPECIFIC_MESSAGE);
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // Here's the public URI used to query for RSS items.
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif public static final Uri CONTENT_URI = Uri
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif .parse("content://test/item");
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // Here are our column name constants, used to query for field values.
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif public static final String ID = "_id";
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif public static final String NAME = "NAME";
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif public static final String VALUE = "VALUE";
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif public static final String DEFAULT_SORT_ORDER = ID + " DESC";
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif private static class DatabaseHelper extends AbstractDatabaseHelper {
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif @Override
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif protected String[] createDBTables() {
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // TODO Auto-generated method stub
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif String sql = "CREATE TABLE " + DATABASE_TABLE_NAME + "(" + ID
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif + " INTEGER PRIMARY KEY AUTOINCREMENT, " + NAME + " TEXT,"
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif + VALUE + " TEXT);";
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif return new String[] { sql };
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif @Override
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif protected String[] dropDBTables() {
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // TODO Auto-generated method stub
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return null;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif @Override
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif protected String getDatabaseName() {
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // TODO Auto-generated method stub
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return DATABASE_NAME;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif @Override
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif protected int getDatabaseVersion() {
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // TODO Auto-generated method stub
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return DB_VERSION;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif @Override
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif protected String getTag() {
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // TODO Auto-generated method stub
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return TestContentProvider.class.getSimpleName();
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif /**
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif *
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif */
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif public TestContentProvider() {
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // TODO Auto-generated constructor stub
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif /*
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * (non-Javadoc)
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif *
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * @see android.content.ContentProvider#delete(android.net.Uri,
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * java.lang.String, java.lang.String[])
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif */
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif @Override
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif public int delete(Uri uri, String selection, String[] selectionArgs) {
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // NOTE Argument checking code omitted. Check your parameters!
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif int rowCount = mDb.delete(DATABASE_TABLE_NAME, selection, selectionArgs);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // Notify any listeners and return the deleted row count.
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif getContext().getContentResolver().notifyChange(uri, null);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return rowCount;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif /*
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * (non-Javadoc)
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif *
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * @see android.content.ContentProvider#getType(android.net.Uri)
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif */
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif @Override
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif public String getType(Uri uri) {
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif switch (URI_MATCHER.match(uri)) {
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif case ALL_MESSAGES:
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return "vnd.android.cursor.dir/rssitem"; // List of items.
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif case SPECIFIC_MESSAGE:
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return "vnd.android.cursor.item/rssitem"; // Specific item.
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif default:
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return null;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif /*
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * (non-Javadoc)
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif *
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * @see android.content.ContentProvider#insert(android.net.Uri,
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * android.content.ContentValues)
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif */
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif @Override
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif public Uri insert(Uri uri, ContentValues values) {
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // NOTE Argument checking code omitted. Check your parameters! Check that
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // your row addition request succeeded!
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif long rowId = -1;
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif rowId = mDb.insert(DATABASE_TABLE_NAME, NAME, values);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif Uri newUri = Uri.withAppendedPath(CONTENT_URI, ""+rowId);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif Log.i("TestContentProvider", "saved a record " + rowId + " " + newUri);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // Notify any listeners and return the URI of the new row.
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif getContext().getContentResolver().notifyChange(CONTENT_URI, null);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return newUri;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif /*
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * (non-Javadoc)
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif *
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * @see android.content.ContentProvider#onCreate()
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif */
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif @Override
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif public boolean onCreate() {
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // TODO Auto-generated method stub
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif try
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif {
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif mDbHelper = new DatabaseHelper();
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif mDbHelper.open(getContext());
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif mDb = mDbHelper.getMDb();
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif }catch(Exception e){
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif e.printStackTrace();
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return true;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif /*
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * (non-Javadoc)
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif *
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * @see android.content.ContentProvider#query(android.net.Uri,
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * java.lang.String[], java.lang.String, java.lang.String[],
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * java.lang.String)
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif */
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif public Cursor query(Uri uri, String[] projection, String selection,
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif String[] selectionArgs, String sortOrder) {
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // We won't bother checking the validity of params here, but you should!
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // SQLiteQueryBuilder is the helper class that creates the
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // proper SQL syntax for us.
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif SQLiteQueryBuilder qBuilder = new SQLiteQueryBuilder();
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // Set the table we're querying.
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif qBuilder.setTables(DATABASE_TABLE_NAME);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // If the query ends in a specific record number, we're
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // being asked for a specific record, so set the
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // WHERE clause in our query.
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif if((URI_MATCHER.match(uri)) == SPECIFIC_MESSAGE){
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif qBuilder.appendWhere("_id=" + uri.getLastPathSegment());
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif Log.i("TestContentProvider", "_id=" + uri.getLastPathSegment());
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // Make the query.
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif Cursor c = qBuilder.query(mDb,
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif projection,
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif selection,
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif selectionArgs,
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif null,
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif null,
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif sortOrder);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif Log.i("TestContentProvider", "get records");
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif c.setNotificationUri(getContext().getContentResolver(), uri);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return c;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif /*
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * (non-Javadoc)
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif *
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * @see android.content.ContentProvider#update(android.net.Uri,
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif * android.content.ContentValues, java.lang.String, java.lang.String[])
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif */
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif @Override
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif public int update(Uri uri, ContentValues values, String selection,
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockStart.gif String[] selectionArgs) {
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // NOTE Argument checking code omitted. Check your parameters!
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif int updateCount = mDb.update(DATABASE_TABLE_NAME, values, selection, selectionArgs);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif // Notify any listeners and return the updated row count.
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif getContext().getContentResolver().notifyChange(uri, null);
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif return updateCount;
http://www.agoit.com/Images/OutliningIndicators/ExpandedSubBlockEnd.gif }
http://www.agoit.com/Images/OutliningIndicators/InBlock.gif
http://www.agoit.com/Images/OutliningIndicators/ExpandedBlockEnd.gif}
http://www.agoit.com/Images/OutliningIndicators/None.gif
页:
[1]