Android--ContentProvider跨程序访问数据

两个程序A和B，

A程序中有两个类，一个继承Activity,一个继承ContentProvider

B程序中有一个类，继承 Activity

 

在A程序中创建一个数据库，数据库中创建两张表，

实现B程序访问A程序数据库中的数据

 

A程序中继承Activity的类：创建数据库，在数据库中创建表，在表中插入数据

 

package cn.mrzhu.test24;import android.app.Activity;import android.content.ContentValues;import android.database.sqlite.SQLiteDatabase;import android.os.Bundle;public class Provider extends Activity {    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);                //创建数据库        SQLiteDatabase db = openOrCreateDatabase("test24.db", MODE_PRIVATE, null);        //创建表        db.execSQL("create table test1 (_id integer, name varchar(20), age integer)");        db.execSQL("create table test2 (_id integer, name varchar(20), age integer)");                //给test1表添加数据        ContentValues values = new ContentValues();        values.put("name", "zhangsan");        values.put("age", 30);        db.insert("test1", "name", values);                values.clear();        values.put("name", "lisi");        values.put("age", 40);        db.insert("test1", "name", values);                //给test2表添加数据        values.clear();        values.put("name", "Peter");        values.put("age", 20);        db.insert("test2", "name", values);                values.clear();        values.put("name", "Mike");        values.put("age", 25);        db.insert("test2", "name", values);    }}

 

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";@Overridepublic int delete(Uri uri, String selection, String[] selectionArgs) {return 0;}@Overridepublic String getType(Uri uri) {// TODO Auto-generated method stubreturn null;}@Overridepublic Uri insert(Uri uri, ContentValues values) {// TODO Auto-generated method stubreturn null;}@Overridepublic 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1um.addURI(AUTHORITY, "test1", 1);um.addURI(AUTHORITY, "test2", 2);return false;}@Overridepublic 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;}@Overridepublic int update(Uri uri, ContentValues values, String selection,String[] selectionArgs) {// TODO Auto-generated method stubreturn 0;}}

 

B程序：通过A程序中继承ContentProvider的类提供的uri访问到A程序的数据

 

package cn.mrzhu.test24x;import android.app.Activity;import android.content.ContentResolver;import android.database.Cursor;import android.net.Uri;import android.os.Bundle;import android.util.Log;public class Main extends Activity {    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);                //取得ContentResolver对象        ContentResolver cr = getContentResolver();        //指定uri并指定操作哪个表        Uri uri = Uri.parse("content://cn.mrzhu.test24/test1");        //执行query方法返回一个结果集        Cursor cs = cr.query(uri, null, null, null, null);        //遍历结果集，取出数据        while(cs.moveToNext()){        Log.i("System.out", "_id" + cs.getInt(0) + "name" + cs.getString(1) + "age" + cs.getInt(2));        }    }}