ContentProvider跨程序访问数据(2)

A程序中继承ContentProvider的类:需在AndroidManifest.xml中注册

<provider android:name="MyContentProvider"
   android:authorities="cn.mrzhu.test24"></provider>

android:authorities="cn.mrzhu.test24"为程序B访问提供uri，只有通过此uri程序B才能访问到A程序中的数据

package cn.mrzhu.test24;

import android.content.ContentProvider;
import android.content.ContentValues;
import android.content.Context;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;

public class MyContentProvider extends ContentProvider{

//Uri过滤器，通过此过滤器可以取出uri最后一个字段
 UriMatcher um;
 static final String AUTHORITY = "cn.mrzhu.test24";
 @Override
 public int delete(Uri uri, String selection, String[] selectionArgs) {
 
  return 0;
 }

@Override
 public String getType(Uri uri) {
  // TODO Auto-generated method stub
  return null;
 }

@Override
 public Uri insert(Uri uri, ContentValues values) {
  // TODO Auto-generated method stub
  return null;
 }

@Override
 public boolean onCreate() {
  //初始化过滤器
  um = new UriMatcher(UriMatcher.NO_MATCH);
  //添加过滤内容，从其他程序传来的uri通过过滤器之后若其字段为test1，则其code为1
  um.addURI(AUTHORITY, "test1", 1);
  um.addURI(AUTHORITY, "test2", 2);
  return false;
 }

@Override
 public Cursor query(Uri uri, String[] projection, String selection,
   String[] selectionArgs, String sortOrder) {
  SQLiteDatabase db = getContext().openOrCreateDatabase("test24.db", Context.MODE_PRIVATE, null);
  Cursor cs = null;
  //将uri过滤，取得返回值
  int code = um.match(uri);
  //根据不同的返回值执行不同的查询语句
  switch(code){
  case 1:
   cs = db.rawQuery("select * from test1", null);
   break;
  case 2:
   cs = db.rawQuery("select * from test2", null);
   break;
  }
  //执行查询语句后将结果集返回
  return cs;
 }

@Override
 public int update(Uri uri, ContentValues values, String selection,
   String[] selectionArgs) {
  // TODO Auto-generated method stub
  return 0;
 }

}