android contentProvider 小例子

服务端：

import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteDatabase.CursorFactory;import android.database.sqlite.SQLiteOpenHelper;public class MyHelper extends SQLiteOpenHelper {public MyHelper(Context context, String name, CursorFactory factory,int version) {super(context, name, factory, version);}@Overridepublic void onCreate(SQLiteDatabase db) {//初始化数据库信息。   创建表，插入几条数据。db.execSQL("create table sister(_id integer primary key autoincrement,name text,age integer)");db.execSQL("insert into sister(name,age) values('小乔',1000)");db.execSQL("insert into sister(name,age) values('陈圆圆',300)");db.execSQL("insert into sister(name,age) values('陈汤圆',400)");db.execSQL("insert into sister(name,age) values('美玲',150)");}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {// TODO Auto-generated method stub}}

import com.example.tz_contentprovider_server.util.MyHelper;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;import android.util.Log;public class MySisterProvider extends ContentProvider {// Activity子类 onCreate()private static final String TAG = "TZ";private static final int ALL = 1;private static final int SINGLE = 2;private static final int CONDITION = 3;private static final int INSERT = 4;private static final String DB_NAME = "TZ_SISTER.db";// UriMatcher 可以匹配特定的uri，并且返回一个结果。private UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH);private MyHelper helper;private SQLiteDatabase db;@Overridepublic boolean onCreate() {Log.i(TAG, "执行CP.onCreate()");initURI();initDB();return true;}private void initDB() {// 得到MyHelperhelper = new MyHelper(getContext(), DB_NAME, null, 1);// 初始化dbdb = helper.getWritableDatabase();}private void initURI() {/* * 将三类特定的uri添加到matcher中。 查询所有 content://com.tz.provider/sisters */matcher.addURI("com.tz.provider", "sisters", ALL);matcher.addURI("com.tz.provider", "sister/#", SINGLE);matcher.addURI("com.tz.provider", "sisterWithCondition", CONDITION);matcher.addURI("com.tz.provider", "insertSister", INSERT);}@Overridepublic String getType(Uri uri) {// TODO Auto-generated method stubreturn null;}@Overridepublic Cursor query(Uri uri, String[] projection, String selection,String[] selectionArgs, String sortOrder) {/* *  * 查询所有 content://com.tz.provider/sisters *  * 查询特定id content://com.tz.provider/sister/4 *  * 查询特定条件 content://com.tz.provider/sisterWithCondition *  *  * Log.i(TAG, "执行CP.query()  "+uri.toString()); */Cursor c = null;int result = matcher.match(uri);switch (result) {case ALL:c = db.rawQuery("select * from sister", null);break;case SINGLE:// uri---content://com.tz.provider/sister/2long id = ContentUris.parseId(uri);c = db.rawQuery("select * from sister where _id=?",new String[] { id + "" });break;case CONDITION:String sql = "select * from sister";if (selection != null) {sql += " where " + selection;}// sql- select * from sister where name like %？%// selectionArgs -- new String[]{ "%圆%" }c = db.rawQuery(sql, selectionArgs);break;case UriMatcher.NO_MATCH:// 抛出异常break;}return c;}@Overridepublic Uri insert(Uri uri, ContentValues values) {// TODO Auto-generated method stubLog.i(TAG, "执行CP.insert()");int result=matcher.match(uri);if(result==INSERT){//  uri-- content://com.tz.provider/insertSisterlong id=db.insert("sister", "_id", values);// newUri --  content://com.tz.provider/insertSister/5Uri newUri=ContentUris.withAppendedId(uri, id);return newUri;}return null;}@Overridepublic int delete(Uri uri, String selection, String[] selectionArgs) {// TODO Auto-generated method stubLog.i(TAG, "执行CP.delete()");return 0;}@Overridepublic int update(Uri uri, ContentValues values, String selection,String[] selectionArgs) {// Log.i(TAG, "执行CP.update()");int rowAffected = 0;int result = matcher.match(uri);switch (result) {case ALL://更新所有。rowAffected=db.update("sister", values, null, null);break;case SINGLE:long id= ContentUris.parseId(uri);rowAffected=db.update("sister", values, "_id=?", new String[]{id+""});break;case CONDITION:rowAffected=db.update("sister", values, selection, selectionArgs);break;case UriMatcher.NO_MATCH:break;}return rowAffected;}}

客户端：

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.widget.Toast;public class MainActivity extends Activity {private ContentResolver cr;private static final String CP_PATH="content://com.tz.provider"; @Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);//利用上下文可以直接获得  内容获得者ContentResolver  的对象。cr=getContentResolver();}//查询所有public void queryAll(View v){Cursor c=cr.query(Uri.parse(CP_PATH+"/sisters"), null, null, null, null);handleCursor(c);}//查询id为2的妹纸。public void querySisterById(View v){//content://com.tz.provider/sister/2Cursor c=cr.query(Uri.parse("content://com.tz.provider/sister/2"), null, null, null, null);handleCursor(c);}//查询名字里面带圆的妹纸public void querySistersWithCondition(View v){//查询特定条件// content://com.tz.provider/sisterWithConditionCursor c=cr.query(Uri.parse("content://com.tz.provider/sisterWithCondition"), null, "name like ?", new String[]{ "%圆%" }, null);handleCursor(c);}private void handleCursor(Cursor c) {//取出所有数据，并且吐司。StringBuffer sb=new StringBuffer();while(c.moveToNext()){sb.append("_id:"+ c.getInt(  c.getColumnIndex("_id")   ) +"    name:"+ c.getString( c.getColumnIndex("name") )  +"   age:"+c.getInt(  c.getColumnIndex("age") )+"\n");}Toast.makeText(MainActivity.this, sb.toString(), 1).show();c.close();}// 查询public void query(View v) {//根据内容获得者以及内容提供者的Authority访问内容提供者的 query()方法/* * projection 列名---字符串数组   * selection 条件                             "_id = ? or name like ?" * selectionArgs 条件值               new String[]{"3","%美%"}; * sortOrder  排序的列 *  * uri -- 统一资源标志 * */// CP_PATH:"content://com.tz.provider"//  content://com.tz.provider/+路径//  content://com.tz.provider/sister  /* *  * 查询所有 * content://com.tz.provider/sisters *  * 查询特定id * content://com.tz.provider/sister/4 *  * 查询特定条件 * content://com.tz.provider/sisterWithCondition *  * */cr.query(Uri.parse(CP_PATH+"/sister/4"), null, null, null, null);}//更新所有妹纸年龄为18岁    public void updateAll(View v){ContentValues values=new ContentValues();values.put("age", 18);int rowAffected=cr.update(Uri.parse(CP_PATH+"/sisters"), values, null, null);Toast.makeText(this, "更新了" + rowAffected + "行", 1).show();}//更新id为2的妹纸 年龄为16岁。public void updateSisterById(View v){ContentValues values=new ContentValues();values.put("age", 16);int rowAffected=cr.update(Uri.parse(CP_PATH+"/sister/2"), values, null, null);Toast.makeText(this, "更新了" + rowAffected + "行", 1).show();}//更新带圆的妹纸的年龄为20岁public void updateSisterWithCondition(View v){ContentValues values=new ContentValues();values.put("age", 20);int rowAffected=cr.update(Uri.parse(CP_PATH+"/sisterWithCondition"), values, "name  like ?", new String[]{"%圆%"});Toast.makeText(this, "更新了" + rowAffected + "行", 1).show();}// 更新public void update(View v) {/* * ContentValues * key-value *      "age" --- 2000 * */cr.update(Uri.parse(CP_PATH), new ContentValues(), null, null);}// 删除public void delete(View v) {cr.delete(Uri.parse(CP_PATH),null, null);}// 增加public void insert(View v) {/*cr.insert(Uri.parse(CP_PATH), new ContentValues());*//* * 增加一条妹纸记录: * name:呵呵 * age:30 * */ContentValues values=new ContentValues();values.put("name", "呵呵");values.put("age", 30);// uri  --  content://com.tz.provider/insertSister/5Uri uri=cr.insert(Uri.parse(CP_PATH+"/insertSister"), values);long id=ContentUris.parseId(uri);Toast.makeText(this, "新增加记录的id:"+id, 1).show();}}

整理自教程

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