Android 使用ContentProvider对外共享数据与监听ContentProvider数据的变化

package cn.itcast.db;import cn.itcast.service.DBOpenHelper;import android.content.ContentProvider;import android.content.ContentUris;import android.content.ContentValues;import android.content.UriMatcher;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.net.Uri;public class PersonProvider extends ContentProvider {private DBOpenHelper dbOpenHelper;private static final UriMatcher MATCHER = new UriMatcher(UriMatcher.NO_MATCH);private static final int PERSONS = 1;private static final int PERSON = 2;static{MATCHER.addURI("cn.itcast.providers.personprovider", "person", PERSONS);MATCHER.addURI("cn.itcast.providers.personprovider", "person/#", PERSON);}//删除person表中的所有记录   /person//删除person表中指定id的记录 /person/10@Overridepublic int delete(Uri uri, String selection, String[] selectionArgs) {SQLiteDatabase db = dbOpenHelper.getWritableDatabase();int count = 0;switch (MATCHER.match(uri)) {case PERSONS:count = db.delete("person", selection, selectionArgs);return count;case PERSON:long id = ContentUris.parseId(uri);String where = "personid="+ id;if(selection!=null && !"".equals(selection)){where = selection + " and " + where;}count = db.delete("person", where, selectionArgs);return count;default:throw new IllegalArgumentException("Unkwon Uri:"+ uri.toString());}}@Overridepublic String getType(Uri uri) {//返回当前操作的数据的mimeTypeswitch (MATCHER.match(uri)) {case PERSONS:return "vnd.android.cursor.dir/person";case PERSON:return "vnd.android.cursor.item/person";default:throw new IllegalArgumentException("Unkwon Uri:"+ uri.toString());}}@Overridepublic Uri insert(Uri uri, ContentValues values) {// /personSQLiteDatabase db = dbOpenHelper.getWritableDatabase();switch (MATCHER.match(uri)) {case PERSONS:long rowid = db.insert("person", "name", values); Uri insertUri = ContentUris.withAppendedId(uri, rowid);//得到代表新增记录的Urithis.getContext().getContentResolver().notifyChange(uri, null);return insertUri;default:throw new IllegalArgumentException("Unkwon Uri:"+ uri.toString());}}@Overridepublic boolean onCreate() {this.dbOpenHelper = new DBOpenHelper(this.getContext());return false;}//查询person表中的所有记录   /person//查询person表中指定id的记录 /person/10@Overridepublic Cursor query(Uri uri, String[] projection, String selection,String[] selectionArgs, String sortOrder) {SQLiteDatabase db = dbOpenHelper.getReadableDatabase();switch (MATCHER.match(uri)) {case PERSONS:return db.query("person", projection, selection, selectionArgs, null, null, sortOrder);case PERSON:long id = ContentUris.parseId(uri);String where = "personid="+ id;if(selection!=null && !"".equals(selection)){where = selection + " and " + where;}return db.query("person", projection, where, selectionArgs, null, null, sortOrder);default:throw new IllegalArgumentException("Unkwon Uri:"+ uri.toString());}}//更新person表中的所有记录   /person//更新person表中指定id的记录 /person/10@Overridepublic int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {SQLiteDatabase db = dbOpenHelper.getWritableDatabase();int count = 0;switch (MATCHER.match(uri)) {case PERSONS:count = db.update("person", values, selection, selectionArgs);return count;case PERSON:long id = ContentUris.parseId(uri);String where = "personid="+ id;if(selection!=null && !"".equals(selection)){where = selection + " and " + where;}count = db.update("person", values, where, selectionArgs);return count;default:throw new IllegalArgumentException("Unkwon Uri:"+ uri.toString());}}}

import android.content.ContentResolver;import android.content.ContentValues;import android.database.Cursor;import android.net.Uri;import android.test.AndroidTestCase;import android.util.Log;
public class AccessContentProviderTest extends AndroidTestCase { private static final String TAG = "AccessContentProviderTest";  /**  * 往内容提供者添加数据  * @throws Throwable  */ public void testInsert() throws Throwable{  ContentResolver contentResolver = this.getContext().getContentResolver();  Uri insertUri = Uri.parse("content://cn.itcast.providers.personprovider/person");  ContentValues values = new ContentValues();  values.put("name", "zhangxiaoxiao");  values.put("amount", 90);  Uri uri = contentResolver.insert(insertUri, values);  Log.i(TAG, uri.toString()); }
 /**  * 更新内容提供者中的数据  * @throws Throwable  */ public void testUpdate() throws Throwable{  ContentResolver contentResolver = this.getContext().getContentResolver();  Uri updateUri = Uri.parse("content://cn.itcast.providers.personprovider/person/1");  ContentValues values = new ContentValues();  values.put("name", "lili");  contentResolver.update(updateUri, values, null, null); }  /**  * 从内容提供者中删除数据  * @throws Throwable  */ public void testDelete() throws Throwable{  ContentResolver contentResolver = this.getContext().getContentResolver();  Uri deleteUri = Uri.parse("content://cn.itcast.providers.personprovider/person/1");  contentResolver.delete(deleteUri, null, null); }  /**  * 获取内容提供者中的数据  * @throws Throwable  */ public void testFind() throws Throwable{  ContentResolver contentResolver = this.getContext().getContentResolver();  Uri selectUri = Uri.parse("content://cn.itcast.providers.personprovider/person");  Cursor cursor = contentResolver.query(selectUri, null, null, null, "personid desc");  while(cursor.moveToNext()){   int id = cursor.getInt(cursor.getColumnIndex("personid"));   String name = cursor.getString(cursor.getColumnIndex("name"));   int amount = cursor.getInt(cursor.getColumnIndex("amount"));   Log.i(TAG, "id="+ id + ",name="+ name+ ",amount="+ amount);  } }}
 

package cn.itcast.other;import android.app.Activity;import android.content.ContentResolver;import android.database.ContentObserver;import android.database.Cursor;import android.net.Uri;import android.os.Bundle;import android.os.Handler;import android.util.Log;public class OtherActivity extends Activity {    private static final String TAG = "OtherActivity";        @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);                Uri insertUri = Uri.parse("content://cn.itcast.providers.personprovider/person");        ContentResolver contentResolver = this.getContentResolver();        //对指定uri进行监听，如果该uri代表的数据发生变化，就会调用PersonObserver中的onChange()        contentResolver.registerContentObserver(insertUri, true, new PersonObserver(new Handler()));    }        private final class PersonObserver extends ContentObserver{public PersonObserver(Handler handler) {super(handler);}@Overridepublic void onChange(boolean selfChange) {ContentResolver contentResolver = getContentResolver();Uri selectUri = Uri.parse("content://cn.itcast.providers.personprovider/person");Cursor cursor = contentResolver.query(selectUri, null, null, null, "personid desc");while(cursor.moveToNext()){int id = cursor.getInt(cursor.getColumnIndex("personid"));String name = cursor.getString(cursor.getColumnIndex("name"));int amount = cursor.getInt(cursor.getColumnIndex("amount"));Log.i(TAG, "id="+ id + ",name="+ name+ ",amount="+ amount);}}        }}