Content Provider数据存储实例
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一、Content Provider基本概念
1、ContentProvider为存储和获取数据提供了统一的接口。ContentProvide对数据进行封装，不用关心数据存储的细节。使用表的形式来组织数据。
2、使用ContentProvider可以在不同的应用程序之间共享数据。3、Android为常见的一些数据提供了默认的ContentProvider（包括音频、视频、图片和通讯录等）。
ContentProvider所提供的函数：
query(),insert(),update(),delete(),getType(),onCreate()等。
为系统的每一个资源给其一个名字，比方说通话记录。
1、每一个ContentProvider都拥有一个公共的URI，这个URI用于表示这个ContentProvider所提供的数据。
2、Android所提供的ContentProvider都存放在android.provider包中。 将其分为A，B，C，D 4个部分：
A：标准前缀，用来说明一个Content Provider控制这些数据，无法改变的；"content://"
B：URI 的标识，它定义了是哪个Content Provider提供这些数据。对于第三方应用程序，为了保证URI标识的唯一性，它必须是一个完整的、小写的 类名。这个标识在 元素的 authorities属性中说明：一般是定义该ContentProvider的包.类的名称;"content://hx.android.text.myprovider"
C：路径，不知道是不是路径，通俗的讲就是你要操作的数据库中表的名字，或者你也可以自己定义，记得在使用的时候保持一致就ok了；"content://hx.android.text.myprovider/tablename"
D：如果URI中包含表示需要获取的记录的ID；则就返回该id对应的数据，如果没有ID，就表示返回全部； "content://hx.android.text.myprovider/tablename/#" #表示数据id
Content Provider增删改查实例（通过listview显示操作过的数据）
1，创建person库，person表
package com.example.contentproviderdemo2;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;public class DBOpenHelper extends SQLiteOpenHelper { private static final String DATABASE_NAME = "person.db"; //数据库名称private static final int DATABASE_VERSION = 1;//数据库版本public DBOpenHelper(Context context) {super(context, DATABASE_NAME, null, DATABASE_VERSION);// TODO Auto-generated constructor stub}@Overridepublic void onCreate(SQLiteDatabase db) { db.execSQL("CREATE TABLE person (_id integer primary key autoincrement, name varchar(20), age varchar(10))");}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {// TODO Auto-generated method stubdb.execSQL("DROP TABLE IF EXISTS person");onCreate(db);}}2，自定义Content Provider类，增删改查的方法
package com.example.contentproviderdemo2;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 PersonProvider extends ContentProvider {private DBOpenHelper dbOpenHelper;private static final UriMatcher MATCHER = new UriMatcher(UriMatcher.NO_MATCH);private static final int PERSONS = 1;private static final int PERSON = 2;static {MATCHER.addURI("cn.com.karl.personProvider", "person", PERSONS);MATCHER.addURI("cn.com.karl.personProvider", "person/#", PERSON);}@Overridepublic boolean onCreate() {// TODO Auto-generated method stubthis.dbOpenHelper = new DBOpenHelper(this.getContext());return false;}@Overridepublic Cursor query(Uri uri, String[] projection, String selection,String[] selectionArgs, String sortOrder) {// TODO Auto-generated method stubSQLiteDatabase db = dbOpenHelper.getReadableDatabase();switch (MATCHER.match(uri)) {case PERSONS://查询所有的return db.query("person", projection, selection, selectionArgs,null, null, sortOrder);case PERSON://查询某一id的人的信息long id = ContentUris.parseId(uri);String where = "_id=" + id;if (selection != null && !"".equals(selection)) {where = selection + " and " + where;}return db.query("person", projection, where, selectionArgs, null,null, sortOrder);default:throw new IllegalArgumentException("Unkwon Uri:" + uri.toString());}} //返回数据的MIME类型。@Overridepublic String getType(Uri uri) {// TODO Auto-generated method stubswitch (MATCHER.match(uri)) {case PERSONS:return "vnd.android.cursor.dir/person";case PERSON:return "vnd.android.cursor.item/person";default:throw new IllegalArgumentException("Unkwon Uri:" + uri.toString());}}// 插入person表中的所有记录 /person// 插入person表中指定id的记录 /person/10@Overridepublic Uri insert(Uri uri, ContentValues values) {// TODO Auto-generated method stubSQLiteDatabase db = dbOpenHelper.getWritableDatabase();switch (MATCHER.match(uri)) {case PERSONS:// 特别说一下第二个参数是当name字段为空时，将自动插入一个NULL。long rowid = db.insert("person", "name", values);Uri insertUri = ContentUris.withAppendedId(uri, rowid);// 得到代表新增记录的Urithis.getContext().getContentResolver().notifyChange(uri, null);return insertUri;default:throw new IllegalArgumentException("Unkwon Uri:" + uri.toString());}}@Overridepublic int delete(Uri uri, String selection, String[] selectionArgs) {// TODO Auto-generated method stubSQLiteDatabase db = dbOpenHelper.getWritableDatabase();int count = 0;switch (MATCHER.match(uri)) {case PERSONS:count = db.delete("person", selection, selectionArgs);return count;case PERSON:long id = ContentUris.parseId(uri);String where = "_id=" + id;if (selection != null && !"".equals(selection)) {where = selection + " and " + where;}count = db.delete("person", where, selectionArgs);return count;default:throw new IllegalArgumentException("Unkwon Uri:" + uri.toString());}}@Overridepublic int update(Uri uri, ContentValues values, String selection,String[] selectionArgs) {// TODO Auto-generated method stubSQLiteDatabase db = dbOpenHelper.getWritableDatabase();int count = 0;switch (MATCHER.match(uri)) {case PERSONS:count = db.update("person", values, selection, selectionArgs);return count;case PERSON:long id = ContentUris.parseId(uri);String where = "_id=" + id;if (selection != null && !"".equals(selection)) {where = selection + " and " + where;}count = db.update("person", values, where, selectionArgs);return count;default:throw new IllegalArgumentException("Unkwon Uri:" + uri.toString());}}} 3，activity
package com.example.contentproviderdemo2;import android.app.Activity;import android.content.ContentResolver;import android.content.ContentValues;import android.database.Cursor;import android.net.Uri;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.AdapterView;import android.widget.AdapterView.OnItemClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.ListView;import android.widget.SimpleCursorAdapter;import android.widget.Toast;public class ResolverDemoActivity extends Activity { /** Called when the activity is first created. */ private SimpleCursorAdapter adapter; private ListView listView; private Button button_insert; private Button button_query; private Button button_query_one; private EditText edittext_query; private Button button_update_one; private EditText edittext_update; private Button button_update; private Button button_delete; private Button button_delete_one; private EditText edittext_delete; @SuppressWarnings("deprecation")@Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); listView=(ListView) this.findViewById(R.id.listView); ContentResolver contentResolver = getContentResolver(); Uri selectUri = Uri.parse("content://cn.com.karl.personProvider/person"); Cursor cursor=contentResolver.query(selectUri, null, null, null, null); adapter = new SimpleCursorAdapter(this, R.layout.item, cursor, new String[]{"_id", "name", "age"}, new int[]{R.id.id, R.id.name, R.id.age}); listView.setAdapter(adapter); listView.setOnItemClickListener(new OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { ListView lView = (ListView)parent; Cursor data = (Cursor)lView.getItemAtPosition(position); int _id = data.getInt(data.getColumnIndex("_id")); Toast.makeText(ResolverDemoActivity.this, _id+"", 1).show(); } }); button_insert = (Button) this.findViewById(R.id.insertbutton); button_insert.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { ContentResolver contentResolver = getContentResolver(); Uri insertUri = Uri.parse("content://cn.com.karl.personProvider/person"); ContentValues values = new ContentValues(); values.put("name", "wangkuifeng"); values.put("age", 23); Uri uri = contentResolver.insert(insertUri, values); Toast.makeText(ResolverDemoActivity.this, "添加完成", 1).show(); } }); button_query = (Button)this.findViewById(R.id.querybutton); button_query.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stub ContentResolver contentResolver = getContentResolver(); Uri selectUri = Uri.parse("content://cn.com.karl.personProvider/person"); Cursor cursor=contentResolver.query(selectUri, null, null, null, null); SimpleCursorAdapter adapter= new SimpleCursorAdapter(ResolverDemoActivity.this, R.layout.item, cursor, new String[]{"_id", "name", "age"}, new int[]{R.id.id, R.id.name, R.id.age}); listView.setAdapter(adapter); Toast.makeText(ResolverDemoActivity.this, "查询完成", 1).show(); }}); button_query_one = (Button)this.findViewById(R.id.queryonebutton); edittext_query = (EditText)this.findViewById(R.id.queryone_et); button_query_one.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubString num = edittext_query.getText().toString();ContentResolver contentResolver = getContentResolver(); Uri selectUri = Uri.parse("content://cn.com.karl.personProvider/person"+"/"+num); Cursor cursor=contentResolver.query(selectUri, null, null, null, null); SimpleCursorAdapter adapter = new SimpleCursorAdapter(ResolverDemoActivity.this, R.layout.item, cursor, new String[]{"_id", "name", "age"}, new int[]{R.id.id, R.id.name, R.id.age}); listView.setAdapter(adapter); Toast.makeText(ResolverDemoActivity.this, "查询完成", 1).show(); }}); edittext_update = (EditText)this.findViewById(R.id.update_et); button_update_one = (Button)this.findViewById(R.id.updateonebutton); button_update_one.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubString num = edittext_update.getText().toString();ContentResolver contentResolver = getContentResolver(); Uri updateUri = Uri.parse("content://cn.com.karl.personProvider/person"+"/"+num); ContentValues values = new ContentValues(); values.put("name", "superjunjin"); values.put("age", 26); int count = contentResolver.update(updateUri, values, null, null); Toast.makeText(ResolverDemoActivity.this, "更新完成", 1).show(); }}); button_update = (Button)this.findViewById(R.id.updatebutton); button_update.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubContentResolver contentResolver = getContentResolver(); Uri updateUri = Uri.parse("content://cn.com.karl.personProvider/person"); ContentValues values = new ContentValues(); values.put("name", "superjunjin"); values.put("age", 26); int count = contentResolver.update(updateUri, values, null, null); Toast.makeText(ResolverDemoActivity.this, "更新完成", 1).show(); }}); button_delete = (Button)this.findViewById(R.id.deletebutton); button_delete.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubContentResolver contentResolver = getContentResolver(); Uri deleteUri = Uri.parse("content://cn.com.karl.personProvider/person");contentResolver.delete(deleteUri, null, null);Toast.makeText(ResolverDemoActivity.this, "删除完成", 1).show(); }}); edittext_delete = (EditText)this.findViewById(R.id.delete_et); button_delete_one = (Button)this.findViewById(R.id.deleteonebutton); button_delete_one.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubString num = edittext_delete.getText().toString();ContentResolver contentResolver = getContentResolver(); Uri deleteUri = Uri.parse("content://cn.com.karl.personProvider/person"+"/"+num); contentResolver.delete(deleteUri, null, null); Toast.makeText(ResolverDemoActivity.this, "删除完成", 1).show();}}); } } 参考 http://blog.csdn.net/wangkuifeng0118/article/details/7028953
http://blog.csdn.net/huangbiao86/article/details/6679823
实例下载 http://download.csdn.net/detail/superjunjin/7245993
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