Support4Demos 源码

/* * Copyright (C) 2011 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.example.android.supportv4.app; //BEGIN_INCLUDE(complete) import android.content.ContentProvider; import android.content.ContentResolver; import android.content.ContentUris; import android.content.ContentValues; import android.content.Context; import android.content.UriMatcher; import android.database.Cursor; import android.database.SQLException; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; import android.database.sqlite.SQLiteQueryBuilder; import android.net.Uri; import android.os.AsyncTask; import android.os.Bundle; import android.provider.BaseColumns; import android.support.v4.app.FragmentActivity; import android.support.v4.app.FragmentManager; import android.support.v4.app.ListFragment; import android.support.v4.app.LoaderManager; import android.support.v4.content.CursorLoader; import android.support.v4.content.Loader; import android.support.v4.database.DatabaseUtilsCompat; import android.support.v4.view.MenuItemCompat; import android.support.v4.widget.SimpleCursorAdapter; import android.text.TextUtils; import android.util.Log; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.View; import android.widget.ListView; import java.util.HashMap; /** * Demonstration of bottom to top implementation of a content provider holding * structured data through displaying it in the UI, using throttling to reduce * the number of queries done when its data changes. */ public class LoaderThrottleSupport extends FragmentActivity { // Debugging. static final String TAG = "LoaderThrottle"; /** * The authority we use to get to our sample provider. */ public static final String AUTHORITY = "com.example.android.apis.supportv4.app.LoaderThrottle"; /** * Definition of the contract for the main table of our provider. */ public static final class MainTable implements BaseColumns { // This class cannot be instantiated private MainTable() {} /** * The table name offered by this provider */ public static final String TABLE_NAME = "main"; /** * The content:// style URL for this table */ public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/main"); /** * The content URI base for a single row of data. Callers must * append a numeric row id to this Uri to retrieve a row */ public static final Uri CONTENT_ID_URI_BASE = Uri.parse("content://" + AUTHORITY + "/main/"); /** * The MIME type of {@link #CONTENT_URI}. */ public static final String CONTENT_TYPE = "vnd.android.cursor.dir/vnd.example.api-demos-throttle"; /** * The MIME type of a {@link #CONTENT_URI} sub-directory of a single row. */ public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/vnd.example.api-demos-throttle"; /** * The default sort order for this table */ public static final String DEFAULT_SORT_ORDER = "data COLLATE LOCALIZED ASC"; /** * Column name for the single column holding our data. * <P>Type: TEXT</P> */ public static final String COLUMN_NAME_DATA = "data"; } /** * This class helps open, create, and upgrade the database file. */ static class DatabaseHelper extends SQLiteOpenHelper { private static final String DATABASE_NAME = "loader_throttle.db"; private static final int DATABASE_VERSION = 2; DatabaseHelper(Context context) { // calls the super constructor, requesting the default cursor factory. super(context, DATABASE_NAME, null, DATABASE_VERSION); } /** * * Creates the underlying database with table name and column names taken from the * NotePad class. */ @Override public void onCreate(SQLiteDatabase db) { db.execSQL("CREATE TABLE " + MainTable.TABLE_NAME + " (" + MainTable._ID + " INTEGER PRIMARY KEY," + MainTable.COLUMN_NAME_DATA + " TEXT" + ");"); } /** * * Demonstrates that the provider must consider what happens when the * underlying datastore is changed. In this sample, the database is upgraded the database * by destroying the existing data. * A real application should upgrade the database in place. */ @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { // Logs that the database is being upgraded Log.w(TAG, "Upgrading database from version " + oldVersion + " to " + newVersion + ", which will destroy all old data"); // Kills the table and existing data db.execSQL("DROP TABLE IF EXISTS notes"); // Recreates the database with a new version onCreate(db); } } /** * A very simple implementation of a content provider. */ public static class SimpleProvider extends ContentProvider { // A projection map used to select columns from the database private final HashMap<String, String> mNotesProjectionMap; // Uri matcher to decode incoming URIs. private final UriMatcher mUriMatcher; // The incoming URI matches the main table URI pattern private static final int MAIN = 1; // The incoming URI matches the main table row ID URI pattern private static final int MAIN_ID = 2; // Handle to a new DatabaseHelper. private DatabaseHelper mOpenHelper; /** * Global provider initialization. */ public SimpleProvider() { // Create and initialize URI matcher. mUriMatcher = new UriMatcher(UriMatcher.NO_MATCH); mUriMatcher.addURI(AUTHORITY, MainTable.TABLE_NAME, MAIN); mUriMatcher.addURI(AUTHORITY, MainTable.TABLE_NAME + "/#", MAIN_ID); // Create and initialize projection map for all columns. This is // simply an identity mapping. mNotesProjectionMap = new HashMap<String, String>(); mNotesProjectionMap.put(MainTable._ID, MainTable._ID); mNotesProjectionMap.put(MainTable.COLUMN_NAME_DATA, MainTable.COLUMN_NAME_DATA); } /** * Perform provider creation. */ @Override public boolean onCreate() { mOpenHelper = new DatabaseHelper(getContext()); // Assumes that any failures will be reported by a thrown exception. return true; } /** * Handle incoming queries. */ @Override public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) { // Constructs a new query builder and sets its table name SQLiteQueryBuilder qb = new SQLiteQueryBuilder(); qb.setTables(MainTable.TABLE_NAME); switch (mUriMatcher.match(uri)) { case MAIN: // If the incoming URI is for main table.