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);
        }
        
    }

    

}

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;
    }

}

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();
    }

}

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