建立ContentProvider_20130223

package com.example.booksystem_20130219;

import android.content.ContentProvider;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.net.Uri;

//在含有資料庫的App中建立一個class繼承ContentProvider
public class BookDBContentProvider extends ContentProvider{
 //建立獨一無二的域名
 private final static String AUTHORITY="tw.com.jimbo.FindBook";
 //供查詢資料表名稱
 private final static String DB_TABLE_NAME="BooksInfo";
 //建立連此資料庫的路徑(URI物件)，注意是public
 public final static Uri CONTENT_URI=Uri.parse("content://"+AUTHORITY+"/"+DB_TABLE_NAME);
 //建立URI根目錄及資料表的子目錄(節點)
 private final static int URI_ROOT=0,DB_TABLE_BOOKS=1;
 //建立URI比對物件，建構式放入URI根目錄(節點)的int值
 private final static UriMatcher myUriMatcher=new UriMatcher(URI_ROOT);
 private BookHelper myBookHelper;
 //預先載入區塊加入URI到這個比對物件
 static{
  myUriMatcher.addURI(AUTHORITY, DB_TABLE_NAME, DB_TABLE_BOOKS);
 }
 
 @Override
 public int delete(Uri uri, String selection, String[] selectionArgs) {
  // TODO Auto-generated method stub
  return 0;
 }

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

 @Override
 public Uri insert(Uri uri, ContentValues values) {
  // TODO Auto-generated method stub
  return null;
 }

 //於onCreate()時期產生BookHelper的物件，產生後回傳true
 @Override
 public boolean onCreate() {
  // TODO Auto-generated method stub
  myBookHelper=new BookHelper(getContext());
  return true;
 }

 //覆寫query方法
 @Override
 public Cursor query(Uri uri, String[] projection, String selection,
   String[] selectionArgs, String sortOrder) {
  // TODO Auto-generated method stub
  //檢查是否為查詢的節點，不是則回傳null
  if(myUriMatcher.match(uri) != DB_TABLE_BOOKS){
   return null;
  }
  Cursor myCursor=myBookHelper.query();  
  return myCursor;
 }

 @Override
 public int update(Uri uri, ContentValues values, String selection,
   String[] selectionArgs) {
  // TODO Auto-generated method stub
  return 0;
 }

}

記得在manifest的application中加入

<provider 

android:name="com.example.booksystem_20130219.BookDBContentProvider"

 android:authorities="tw.com.jimbo.FindBook">            
</provider>