ContentProvider-------------自定义的内容提供者 然后去访问

自定义提供者

 import android.content.Context;
 import android.database.DatabaseErrorHandler;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteDatabase.CursorFactory;
 import android.database.sqlite.SQLiteOpenHelper;

 public class DBHelper extends SQLiteOpenHelper {

     public DBHelper(Context context) {
         super(context, "users.db", null, 1);
     }

     @Override
     public void onCreate(SQLiteDatabase db) {
         // TODO 初始化数据库
         db.execSQL("create table t_user(_id integer primary key,uname,upass,money)");

         db.execSQL("create table t_order(_id integer primary key,user_id,price,productname)");

         db.execSQL("insert into t_user(uname,upass,money) values('lisi','123',200)");

         db.execSQL("insert into t_user(uname,upass,money) values('zhangsi','1234',2000)");
     }

     @Override
     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
         // TODO 数据库升级时执行该方法
         if(newVersion>oldVersion)
         {
             db.execSQL("drop table if exists t_user");
             db.execSQL("drop table if exists t_order");
             //并且重新初始化数据库也可以不重新加载
             onCreate(db);
         }

     }

 }

DBHelper

 import com.qianfeng.gp08_day25_contentprovider1.tool.DBHelper;

 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 UserContentProvider extends ContentProvider {

     //声明该ContentProvider的唯一标识--通常使用包名+数据库名--必须小写
     public static final String AUTHORITY ="com.qianfeng.gp08_day25_contentprovider1.users";

     //为该组件中可以被外界访问的数据库中的资源定义Code标识
     public static final int CODE_USER = 1;
     public static final int CODE_ORDER = 8;

     //定义访问资源的Uri的匹配器对象--使用该类生成被访问的资源的Uri
     private static UriMatcher uriMatcher;

     static{
         uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
         //content://com.qianfeng.gp08_day25_contentprovider1.users/user
         uriMatcher.addURI(AUTHORITY, "user", CODE_USER);

         //content://com.qianfeng.gp08_day25_contentprovider1.users/order
         uriMatcher.addURI(AUTHORITY, "order", CODE_ORDER);
     }

     private DBHelper dbHelper;

     @Override
     public boolean onCreate() {
         // TODO 初始化 数据库操作的工具类
         dbHelper = new DBHelper(getContext());
         return false;
     }

     @Override
     public Cursor query(Uri uri, String[] projection, String selection,
             String[] selectionArgs, String sortOrder) {
         SQLiteDatabase  db = dbHelper.getReadableDatabase();
         Cursor cursor = null;

         int code = uriMatcher.match(uri);

         switch(code)
         {
         case CODE_USER:
             cursor = db.query("t_user", projection, selection, selectionArgs, null, null, sortOrder);
             break;
         case CODE_ORDER:
             cursor = db.query("t_order", projection, selection, selectionArgs, null, null, sortOrder);
             break;
         }
         return cursor;
     }

     @Override
     public Uri insert(Uri uri, ContentValues values) {
         // TODO 向数据库中插入数据
         SQLiteDatabase db =dbHelper.getWritableDatabase();
         if(uriMatcher.match(uri)==CODE_USER)
         {
             long id = db.insert("t_user", null, values);

             //返回新插入的记录的 Uri
             //content://com.qianfeng.gp08_day25_contentprovider1.users/user/6
             return ContentUris.withAppendedId(uri, id);
         }
         return null;
     }

     @Override
     public int delete(Uri uri, String selection, String[] selectionArgs) {
         // TODO 删除数据库中的数据
         SQLiteDatabase db = dbHelper.getWritableDatabase();
         int num = 0;
         if(uriMatcher.match(uri)==CODE_USER)
         {
             num = db.delete("t_user", selection, selectionArgs);
         }
         return num;
     }

     @Override
     public int update(Uri uri, ContentValues values, String selection,
             String[] selectionArgs) {
         // TODO 修改数据库中的数据
         SQLiteDatabase db = dbHelper.getWritableDatabase();
         if(uriMatcher.match(uri)==CODE_USER)
         {
             return db.update("t_user", values, selection, selectionArgs);
         }
         return 0;
     }

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

 }

usercontentprovider

查询

 package com.qianfeng.gp08_day25_contentresolver3;

 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;

 import entity.Person;
 import android.net.Uri;
 import android.os.Bundle;
 import android.app.Activity;
 import android.app.AlertDialog;
 import android.content.ContentResolver;
 import android.content.ContentUris;
 import android.content.ContentValues;
 import android.content.DialogInterface;
 import android.content.DialogInterface.OnClickListener;
 import android.database.Cursor;
 import android.view.ContextMenu;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
 import android.view.ContextMenu.ContextMenuInfo;
 import android.view.View.OnCreateContextMenuListener;
 import android.widget.AdapterView.AdapterContextMenuInfo;
 import android.widget.ArrayAdapter;
 import android.widget.EditText;
 import android.widget.ListView;
 import android.widget.Toast;

 /**
  * 访问自定义的ContentProvider---UserContentProvider
  *
  * @author qq
  *
  */
 public class MainActivity extends Activity {

     private ListView listView;
     private List<Person> datas;
     private ArrayAdapter adapter;

     private Uri userUri = Uri
             .parse("content://com.qianfeng.gp08_day25_contentprovider1.users/user");
     private String[] columns = { "_id", "uname", "upass", "money" };
     private int current;
     private boolean isAdd;
     private EditText edit_name, edit_pass, edit_money;
     private View view;
     private AlertDialog editDialog, deleteDialog;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         listView = (ListView) findViewById(R.id.listView);
         edit_name = (EditText) findViewById(R.id.edit_name);
         edit_pass = (EditText) findViewById(R.id.edit_pass);
         edit_money = (EditText) findViewById(R.id.edit_money);
         datas = new ArrayList<Person>();
         adapter = new ArrayAdapter<Person>(this,
                 android.R.layout.simple_list_item_1, datas);

         listView.setAdapter(adapter);
         registerForContextMenu(listView);

         loadData();
         initDialog();
     }

     private void loadData() {

         Cursor cursor = getContentResolver().query(userUri, columns, null,
                 null, null);

         while (cursor.moveToNext()) {
             long id = cursor.getLong(0);
             String name = cursor.getString(1);
             String pass = cursor.getString(2);
             int money = cursor.getInt(3);
             Person person = new Person();
             person.set_id(id);
             person.setMoney(money);
             person.setUname(name);
             datas.add(person);
         }
         cursor.close();//-------------------------
         adapter.notifyDataSetChanged();
     }

     @Override
     public void onCreateContextMenu(ContextMenu menu, View v,
             ContextMenuInfo menuInfo) {
         getMenuInflater().inflate(R.menu.item, menu);
         current = ((AdapterContextMenuInfo) menuInfo).position;
         super.onCreateContextMenu(menu, v, menuInfo);
     }

     @Override
     public boolean onContextItemSelected(MenuItem item) {
         switch (item.getItemId()) {
         case R.id.action_update:
             isAdd = false;
             edit_name.setText(datas.get(current).getUname());
             edit_pass.setText(datas.get(current).getPass());
             edit_money.setText("" + datas.get(current).getMoney());
             editDialog.show();
             break;
         case R.id.action_delete:
             deleteDialog.show();
             break;
         case R.id.action_add:
             isAdd = true;
             edit_name.setText("");
             edit_pass.setText("");
             edit_money.setText("");
             editDialog.show();
             break;
         }
         return super.onContextItemSelected(item);
     }

     private void showDatas() {
         datas.clear();
         ContentResolver resolver = getContentResolver();
         // 先从联系人表中查询所有人的信息
         Cursor cursor = resolver.query(userUri, columns, null, null, null);
         while (cursor.moveToNext()) {
             long id = cursor.getLong(0);
             String name = cursor.getString(1);
             String pass = cursor.getString(2);
             int money = cursor.getInt(3);
             Person person = new Person();
             person.set_id(id);
             person.setMoney(money);
             person.setUname(name);
             person.setPass(pass);
             datas.add(person);
         }
         cursor.close();//----------------------
         adapter.notifyDataSetChanged();
     }

     public void initDialog() {
         view = getLayoutInflater().inflate(R.layout.dialog, null);
         edit_name = (EditText) view.findViewById(R.id.edit_name);
         edit_pass = (EditText) view.findViewById(R.id.edit_pass);
         edit_money = (EditText) view.findViewById(R.id.edit_money);

         editDialog = new AlertDialog.Builder(this).setTitle("联系人添加对话框")
                 .setIcon(android.R.drawable.ic_menu_add).setView(view)
                 .setPositiveButton("确定", new OnClickListener() {
                     @Override
                     public void onClick(DialogInterface dialog, int which) {
                         String name = edit_name.getText().toString();
                         String pass = edit_pass.getText().toString();
                         String money = edit_money.getText().toString();

                         ContentValues value = new ContentValues();

                         if (isAdd) {
                             if(!name.equals(""))
                             {
                             value.put("uname", name);
                             value.put("upass", pass);
                             value.put("money", money);
                             getContentResolver().insert(userUri, value);
                             }
                             else Toast.makeText(MainActivity.this, "名字不能为空", Toast.LENGTH_SHORT).show();
                         } else {
                             value.put("uname", name);
                             value.put("upass", pass);
                             value.put("money", money);
                             long id = datas.get(current).get_id();
                             getContentResolver().update(userUri, value, "_id="+id, null);
                         }
                         showDatas();
                     }
                 }).setNegativeButton("取消", null).setCancelable(false).create();

         deleteDialog = new AlertDialog.Builder(this).setTitle("提示")
                 .setMessage("确实要删除吗?")
                 .setIcon(android.R.drawable.ic_menu_delete)
                 .setPositiveButton("确定", new OnClickListener() {

                     @Override
                     public void onClick(DialogInterface dialog, int which) {
                         long id = datas.get(current).get_id();
                         getContentResolver().delete(userUri, "_id=" + id, null);

                         showDatas();
                     }
                 }).setNegativeButton("取消", null).setCancelable(false).create();
     }

 }

MainActivity

查询结果放在listView中长按有上下文菜单选择增删改访问数据库操作数据库