http://blog.csdn.net/woshixuye/article/details/8280879
实例代码
当数据需要在应用程序间共享时，我们就可以利用ContentProvider为数据定义一个URI。之后其他应用程序对数据进行查询或者修改时，只需要从当前上下文对象获得一个ContentResolver(内容解析器)传入相应的URI就可以了。
contentProvider和Activity一样是Android的组件，故使用前需要在AndroidManifest.xml中注册，必须放在主应用所在包或其子包下。
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".MainActivity"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<intent-filter>
<data android:mimeType="vnd.android.cursor.dir/person" />
</intent-filter>
<intent-filter>
<data android:mimeType="vnd.android.cursor.item/person" />
</intent-filter>
</activity>
<!-- 配置内容提供者,android:authorities为该内容提供者取名作为在本应用中的唯一标识 -->
<provider android:name=".providers.PersonProvider"
android:authorities="cn.xyCompany.providers.personProvider"/>
</application> 内容提供者和测试代码
package cn.xy.cotentProvider.app.providers;
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;
import android.util.Log;
import cn.xy.cotentProvider.service.DBOpeningHelper; /**
* contentProvider作为一种组件必须放在应用所在包或其子包下，主要作用是对外共享数据
* 测试步骤1：将本项目先部署
* 测试步骤2：调用测试方法
* @author xy
*
*/
public class PersonProvider extends ContentProvider
{
private DBOpeningHelper dbHelper; // 若不匹配采用UriMatcher.NO_MATCH(-1)返回
private static final UriMatcher MATCHER = new UriMatcher(UriMatcher.NO_MATCH); // 匹配码
private static final int CODE_NOPARAM = 1;
private static final int CODE_PARAM = 2; static
{
// 对等待匹配的URI进行匹配操作，必须符合cn.xyCompany.providers.personProvider/person格式
// 匹配返回CODE_NOPARAM，不匹配返回-1
MATCHER.addURI("cn.xyCompany.providers.personProvider", "person", CODE_NOPARAM); // #表示数字 cn.xyCompany.providers.personProvider/person/10
// 匹配返回CODE_PARAM，不匹配返回-1
MATCHER.addURI("cn.xyCompany.providers.personProvider", "person/#", CODE_PARAM);
} @Override
public boolean onCreate()
{
dbHelper = new DBOpeningHelper(this.getContext());
return true;
} /**
* 外部应用向本应用插入数据
*/
@Override
public Uri insert(Uri uri, ContentValues values)
{
SQLiteDatabase db = dbHelper.getWritableDatabase();
switch (MATCHER.match(uri))
{
case CODE_NOPARAM:
// 若主键值是自增长的id值则返回值为主键值，否则为行号，但行号并不是RecNo列
long id = db.insert("person", "name", values);
Uri insertUri = ContentUris.withAppendedId(uri, id);
return insertUri;
default:
throw new IllegalArgumentException("this is unkown uri:" + uri);
}
} /**
* 外部应用向本应用删除数据
*/
@Override
public int delete(Uri uri, String selection, String[] selectionArgs)
{
SQLiteDatabase db = dbHelper.getWritableDatabase();
switch (MATCHER.match(uri))
{
case CODE_NOPARAM:
return db.delete("person", selection, selectionArgs); // 删除所有记录
case CODE_PARAM:
long id = ContentUris.parseId(uri); // 取得跟在URI后面的数字
Log.i("provider", String.valueOf(id));
String where = "id = " + id;
if (null != selection && !"".equals(selection.trim()))
{
where += " and " + selection;
}
return db.delete("person", where, selectionArgs);
default:
throw new IllegalArgumentException("this is unkown uri:" + uri);
}
} /**
* 外部应用向本应用更新数据
*/
@Override
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs)
{
SQLiteDatabase db = dbHelper.getWritableDatabase();
switch (MATCHER.match(uri))
{
case CODE_NOPARAM:
return db.update("person",values,selection, selectionArgs); // 更新所有记录
case CODE_PARAM:
long id = ContentUris.parseId(uri); // 取得跟在URI后面的数字
String where = "id = " + id;
if (null != selection && !"".equals(selection.trim()))
{
where += " and " + selection;
}
return db.update("person",values,where,selectionArgs);
default:
throw new IllegalArgumentException("this is unkown uri:" + uri);
}
} /**
* 返回对应的内容类型
* 如果返回集合的内容类型，必须以vnd.android.cursor.dir开头
* 如果是单个元素，必须以vnd.android.cursor.item开头
*/
@Override
public String getType(Uri uri)
{
switch(MATCHER.match(uri))
{
case CODE_NOPARAM:
return "vnd.android.cursor.dir/person";
case CODE_PARAM:
return "vnd.android.cursor.item/person";
default:
throw new IllegalArgumentException("this is unkown uri:" + uri);
}
} @Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)
{
SQLiteDatabase db = dbHelper.getReadableDatabase();
switch (MATCHER.match(uri))
{
case CODE_NOPARAM:
return db.query("person", projection, selection, selectionArgs, null, null, sortOrder);
case CODE_PARAM:
long id = ContentUris.parseId(uri); // 取得跟在URI后面的数字
String where = "id = " + id;
if (null != selection && !"".equals(selection.trim()))
{
where += " and " + selection;
}
return db.query("person", projection, where, selectionArgs, null, null, sortOrder);
default:
throw new IllegalArgumentException("this is unkown uri:" + uri);
}
} } 测试代码
package cn.xy.test.test;
import android.content.ContentResolver;
import android.content.ContentValues;
import android.database.Cursor;
import android.net.Uri;
import android.test.AndroidTestCase;
import android.util.Log; /**
* 测试代码
* @author xy
*
*/
public class TestProviders extends AndroidTestCase
{
// 在执行该测试方法时需要先将还有内容提供者的项目部署到Android中，否则无法找到内容提供者
public void testInsert()
{
Uri uri = Uri.parse("content://cn.xyCompany.providers.personProvider/person");
ContentResolver resolver = this.getContext().getContentResolver();
ContentValues values = new ContentValues();
values.put("name", "xy");
values.put("phone", "111");
resolver.insert(uri, values); // 内部调用内容提供者的insert方法
} // 不带id参数的删除
public void testDelete1()
{
Uri uri = Uri.parse("content://cn.xyCompany.providers.personProvider/person");
ContentResolver resolver = this.getContext().getContentResolver();
int rowAffect = resolver.delete(uri, null, null);
Log.i("rowAffect", String.valueOf(rowAffect));
} // 带参数的删除，通过URI传递了id至contentProvider并可追加其他条件
public void testDelete2()
{
Uri uri = Uri.parse("content://cn.xyCompany.providers.personProvider/person/18");
ContentResolver resolver = this.getContext().getContentResolver();
int rowAffect = resolver.delete(uri, "name = ?", new String[] { "XY2" }); // 在provider中手动进行了拼装
Log.i("rowAffect", String.valueOf(rowAffect));
} public void testUpdate()
{
Uri uri = Uri.parse("content://cn.xyCompany.providers.personProvider/person/19");
ContentResolver resolver = this.getContext().getContentResolver();
ContentValues values = new ContentValues();
values.put("name", "newxy");
values.put("phone", "new111");
int rowAffect = resolver.update(uri, values, null, null);
Log.i("rowAffect", String.valueOf(rowAffect));
} public void testQuery()
{
Uri uri = Uri.parse("content://cn.xyCompany.providers.personProvider/person/19");
ContentResolver resolver = this.getContext().getContentResolver();
Cursor cursor = resolver.query(uri, new String[]{"id","name","phone"}, null, null, "id asc");
if(cursor.moveToFirst())
{
Log.i("query", cursor.getString(cursor.getColumnIndex("name")));
}
cursor.close();
}
}