android中数据存储的ContentProvider的使用方法-白红宇

android中数据存储的ContentProvider的使用方法

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发布时间：2019-06-23

本文共 13726 字，大约阅读时间需要 45 分钟。

元数据接口

package com.example.contentproviderprojecrt;

import android.net.Uri;

import android.provider.BaseColumns;

public interface MLDNbatabaseMetaData {

//外部访问，content地址://com.example.contentproviderproject

public static final String AUTHORITY="com.example.contentproviderproject";

//数据库的名称

public static final String DATABASE_NAME="mldn.db";

//数据库的版本

public static final int VERSION=1;

//member表的元素定义，直接继承与_ID和_COUNT静态变量

public static interface MemberTableMetaData extends BaseColumns{

//数据表的名称

public static final String TABLE_NAME="member";

//外部访问的URI地址

public static final Uri CONTENT_URI=Uri.parse("content://"+

AUTHORITY+"/"+TABLE_NAME);

//取得member表中的所有数据

public static final String CONTACT_LIST="vnd.android.cursor.dir/vnd.contentproviderproject.member";

//取得一个member信息

public static final String CONTACT_ITEM="vnd.android.cursor.item/vnd.contentproviderproject.member";

//字段名称

public static final String MEMBER_NAME="name";

public static final String MEMBER_AGE="age";

public static final String MEMBER_BIRTHDAY="birthday";

//显示时候的排序字段

public static final String SORT_ORDER="_id DESC";

}

定义数据库操作类助手

package com.example.contentproviderprojecrt;

import android.content.Context;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteDatabase.CursorFactory;

import android.database.sqlite.SQLiteOpenHelper;

public class MyDatabaseHelper extends SQLiteOpenHelper {

public MyDatabaseHelper(Context context) {

//创建数据库

super(context, MLDNbatabaseMetaData.DATABASE_NAME, null, MLDNbatabaseMetaData.VERSION);

}

@Override

public void onCreate(SQLiteDatabase db) {

// 创建表

String sql="CREATE TABLE "+MLDNbatabaseMetaData.MemberTableMetaData.TABLE_NAME+" ("

+MLDNbatabaseMetaData.MemberTableMetaData._ID+" INTEGER PRIMARY KEY,"

+MLDNbatabaseMetaData.MemberTableMetaData.MEMBER_NAME+" VARCHAR(50) NOT NULL,"

+MLDNbatabaseMetaData.MemberTableMetaData.MEMBER_AGE+" INTEGER NOT NULL,"

+MLDNbatabaseMetaData.MemberTableMetaData.MEMBER_BIRTHDAY+" DATE NOT NULL"

+")";

db.execSQL(sql);//执行SQL语句

}

@Override

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

//更新表

String sql="DROP TABLE IF EXISTS "+MLDNbatabaseMetaData.MemberTableMetaData.TABLE_NAME;

db.execSQL(sql);//执行SQL语句

this.onCreate(db);//更新数据库

}

定义表操作contentProvider类

package com.example.contentproviderprojecrt;

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 MemberContentProvider extends ContentProvider {

private static UriMatcher uriMatcher=null; //定义UriMatcher对象

private static final int GET_MEMBER_LIST=1; //查询全部的常量标记

private static final int GET_MEMBER_ITEM=2; //根据ID查询的常量标记

private MyDatabaseHelper helper=null; //数据库操作类对象

static{

uriMatcher=new UriMatcher(uriMatcher.NO_MATCH); //实例化UriMatcher

uriMatcher.addURI(MLDNbatabaseMetaData.AUTHORITY,

MLDNbatabaseMetaData.MemberTableMetaData.TABLE_NAME, GET_MEMBER_LIST);//增加匹配项

uriMatcher.addURI(MLDNbatabaseMetaData.AUTHORITY,

MLDNbatabaseMetaData.MemberTableMetaData.TABLE_NAME+"/#", GET_MEMBER_ITEM);//增加匹配项

}

//删除数据操作

@Override

public int delete(Uri uri, String selection, String[] selectionArgs) {

SQLiteDatabase db=this.helper.getWritableDatabase(); //以写的方式打开

int result=0;//操作结果

switch(uriMatcher.match(uri)){//匹配传入的Uri

case GET_MEMBER_LIST:

result=db.delete(MLDNbatabaseMetaData.MemberTableMetaData.TABLE_NAME, selection, selectionArgs);

break;

case GET_MEMBER_ITEM:

long id=ContentUris.parseId(uri);

String where="_id="+id;

result=db.delete(MLDNbatabaseMetaData.MemberTableMetaData.TABLE_NAME, where, selectionArgs);

break;

default:

throw new UnsupportedOperationException("NOT SUPPORT OPERATION "+uri);

}

return result;

}

@Override

public String getType(Uri uri) {

switch(uriMatcher.match(uri)){//匹配传入的Uri

case GET_MEMBER_LIST:

return MLDNbatabaseMetaData.MemberTableMetaData.CONTACT_LIST;

case GET_MEMBER_ITEM:

return MLDNbatabaseMetaData.MemberTableMetaData.CONTACT_ITEM;

default:

throw new UnsupportedOperationException("NOT SUPPORT OPERATION "+uri);//抛出异常

}

@Override

public Uri insert(Uri uri, ContentValues values) {

SQLiteDatabase db=this.helper.getWritableDatabase();//以写的方式打开

long id=0; //增加之后的ID

switch(uriMatcher.match(uri)){//匹配传入的Uri

case GET_MEMBER_LIST:

id=db.insert(MLDNbatabaseMetaData.MemberTableMetaData.TABLE_NAME,

MLDNbatabaseMetaData.MemberTableMetaData._ID, values);

String uriPath=uri.toString();//取出地址

String path=uriPath+"/"+id; //建立新的URI地址

return Uri.parse(path);

case GET_MEMBER_ITEM:

return null;

default:

throw new UnsupportedOperationException("NOT SUPPORT OPERATION "+uri);

}

@Override

public boolean onCreate() {

this.helper=new MyDatabaseHelper(super.getContext()); //实例化DatabaseHelper

return true; //操作成功

}

@Override

public Cursor query(Uri uri, String[] projection, String selection,

String[] selectionArgs, String sortOrder) {

SQLiteDatabase db=this.helper.getReadableDatabase();//以读的方式打开

switch(uriMatcher.match(uri)){ //匹配传入的Uri

case GET_MEMBER_LIST:

return db.query(MLDNbatabaseMetaData.MemberTableMetaData.TABLE_NAME,

projection, selection, selectionArgs, null, null, sortOrder);

case GET_MEMBER_ITEM:

long id=ContentUris.parseId(uri);

String where="_id="+id;

return db.query(MLDNbatabaseMetaData.MemberTableMetaData.TABLE_NAME, projection, where, selectionArgs, null, null, sortOrder);

default:

throw new UnsupportedOperationException("NOT SUPPORT OPERATION "+uri);

}

@Override

public int update(Uri uri, ContentValues values, String selection,

String[] selectionArgs) {

SQLiteDatabase db=this.helper.getWritableDatabase();//以写的方式打开

int result=0; //操作结果

switch(uriMatcher.match(uri)){//匹配传入的Uri

case GET_MEMBER_LIST:

result=db.update(MLDNbatabaseMetaData.MemberTableMetaData.TABLE_NAME, values, null, null);

break;

case GET_MEMBER_ITEM:

long id=ContentUris.parseId(uri);

String where="_id="+id;

result=db.update(MLDNbatabaseMetaData.MemberTableMetaData.TABLE_NAME, values, where, selectionArgs);

break;

default:

throw new UnsupportedOperationException("NOT SUPPORT OPERATION "+uri);

}

return result;

}

Acitivity程序

package com.example.contentproviderprojecrt;

import java.text.SimpleDateFormat;

import java.util.ArrayList;

import java.util.Date;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import android.net.Uri;

import android.os.Bundle;

import android.app.Activity;

import android.content.ContentResolver;

import android.content.ContentUris;

import android.content.ContentValues;

import android.database.Cursor;

import android.view.Menu;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.ListView;

import android.widget.SimpleAdapter;

import android.widget.Toast;

public class MainActivity extends Activity {

private Button insertBut=null;

private Button updateBut=null;

private Button deleteBut=null;

private Button queryBut=null;

private ListView memberList=null;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

super.setContentView(R.layout.activity_main);

this.insertBut=(Button)super.findViewById(R.id.insertBut);//获取按钮

this.insertBut.setOnClickListener(new InsertOnClickListener());//设置按钮单击事件

this.updateBut=(Button)super.findViewById(R.id.updateBut);//获取按钮

this.updateBut.setOnClickListener(new UpdateOnClickListener());//设置按钮单击事件

this.deleteBut=(Button)super.findViewById(R.id.deleteBut);//获取按钮

this.deleteBut.setOnClickListener(new DeleteOnClickListener());//设置按钮单击事件

this.queryBut=(Button)super.findViewById(R.id.queryBut);//获取按钮

this.queryBut.setOnClickListener(new QueryOnClickListener());//设置按钮单击事件

this.memberList=(ListView)super.findViewById(R.id.memberList);//获取ListView

}

private class QueryOnClickListener implements OnClickListener{//查询按钮事件

@Override

public void onClick(View v) {

Cursor result=MainActivity.this.textQuery(null);//查询的结果集

List<Map<String, Object>> list=new ArrayList<Map<String,Object>>();//用于设置SimpleAdapter

for(result.moveToFirst();!result.isAfterLast();result.moveToNext()){//循环取出数据

Map<String,Object> map=new HashMap<String, Object>();

map.put("_id", result.getInt(0));

map.put("name", result.getString(1));

map.put("age", result.getInt(2));

map.put("birthday", result.getString(3));

list.add(map); //保存取出的数据

}

MainActivity.this.memberList.setAdapter(new SimpleAdapter(

MainActivity.this, //将数据包装

list, //数据集合

R.layout.member,//显示的布局文件

new String[]{"_id","name","age","birthday"}, //匹配的Map key

new int[]{R.id._id,R.id.name,R.id.age,R.id.birthday})); //布局文件里面对应的ID

}

private class DeleteOnClickListener implements OnClickListener{//删除按钮事件

@Override

public void onClick(View v) {

long result=0;//返回删除了多少条数据

result=MainActivity.this.textDelete(String.valueOf(2));

Toast.makeText(MainActivity.this, "result="+result, Toast.LENGTH_LONG).show();

}

private class UpdateOnClickListener implements OnClickListener{//更新按钮事件

@Override

public void onClick(View v) {

long result=0;//返回更新了多少条数据

result=MainActivity.this.textUpdate("1", "李元静", 18, "1998-01-01");

Toast.makeText(MainActivity.this, "result="+result, Toast.LENGTH_LONG).show();

}

private class InsertOnClickListener implements OnClickListener{//增加按钮事件

@Override

public void onClick(View v) {

long id=0;//保存接受ID

id=MainActivity.this.textInsert("李元静", 21, new SimpleDateFormat("yyyy-MM-dd").format(new Date()));

Toast.makeText(MainActivity.this, "id="+id, Toast.LENGTH_LONG).show();

}

private Cursor textQuery(String _id){

if(_id==null || "".equals(_id)){//查询全部数据

return super.getContentResolver().query(

MLDNbatabaseMetaData.MemberTableMetaData.CONTENT_URI

, null, null, null,

MLDNbatabaseMetaData.MemberTableMetaData.SORT_ORDER);

}else{//查询指定ID数据

return super.getContentResolver().query(

Uri.withAppendedPath(MLDNbatabaseMetaData.MemberTableMetaData.CONTENT_URI, _id)

, null, null, null,

MLDNbatabaseMetaData.MemberTableMetaData.SORT_ORDER);

}

private long textDelete(String _id){

ContentResolver contentSesolver=super.getContentResolver();//定义取得ContentResolver对象

int result=0;

if(_id==null || "".equals(_id)){//删除全部数据

result=contentSesolver.delete(MLDNbatabaseMetaData.MemberTableMetaData.CONTENT_URI, null, null);

}else{//删除指定数据

result=contentSesolver.delete(Uri.withAppendedPath(MLDNbatabaseMetaData.MemberTableMetaData.CONTENT_URI, _id), null, null);

}

return result;

}

private long textInsert(String name,int age,String birthday){

ContentResolver contentSesolver=null;//定义ContentResolver

contentSesolver=super.getContentResolver();//取得contentSesolver

ContentValues values=new ContentValues();//设置内容

values.put(MLDNbatabaseMetaData.MemberTableMetaData.MEMBER_NAME, name);

values.put(MLDNbatabaseMetaData.MemberTableMetaData.MEMBER_AGE, age);

values.put(MLDNbatabaseMetaData.MemberTableMetaData.MEMBER_BIRTHDAY, birthday);

Uri resultUri=contentSesolver.insert(MLDNbatabaseMetaData.MemberTableMetaData.CONTENT_URI, values);

return ContentUris.parseId(resultUri);//解析ID返回

}

private long textUpdate(String _id,String name,int age,String birthday){

long result=0;

ContentResolver contentSesolver=null; //定义ContentResolver

contentSesolver=super.getContentResolver();//取得contentSesolver

ContentValues values=new ContentValues();//设置内容

values.put(MLDNbatabaseMetaData.MemberTableMetaData.MEMBER_NAME, name);

values.put(MLDNbatabaseMetaData.MemberTableMetaData.MEMBER_AGE, age);

values.put(MLDNbatabaseMetaData.MemberTableMetaData.MEMBER_BIRTHDAY, birthday);

if(_id==null || "".equals(_id)){//更新全部

result=contentSesolver.update(MLDNbatabaseMetaData.MemberTableMetaData.CONTENT_URI, values, null, null);

}else{//更新制定数据

result=contentSesolver.update(

Uri.withAppendedPath(MLDNbatabaseMetaData.MemberTableMetaData.CONTENT_URI,

_id), values, null, null);

}

Uri resultUri=contentSesolver.insert(MLDNbatabaseMetaData.MemberTableMetaData.CONTENT_URI, values);

return result;

}

@Override

public boolean onCreateOptionsMenu(Menu menu) {

// Inflate the menu; this adds items to the action bar if it is present.

getMenuInflater().inflate(R.menu.main, menu);

return true;

}

Layout:activity_mail.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent" >

<LinearLayout

android:orientation="horizontal"

android:layout_width="fill_parent"

android:layout_height="wrap_content" >

<Button

android:id="@+id/insertBut"