diff --git a/MiNote/doc/孙祖凯-2023317168-小米便签泛读报告.docx b/MiNote/doc/孙祖凯-2023317168-小米便签泛读报告.docx new file mode 100644 index 0000000..5c3449e Binary files /dev/null and b/MiNote/doc/孙祖凯-2023317168-小米便签泛读报告.docx differ diff --git a/MiNote/src/net/micode/notes/data/Contact.java b/MiNote/src/net/micode/notes/data/Contact.java index d97ac5d..f5f2f12 100644 --- a/MiNote/src/net/micode/notes/data/Contact.java +++ b/MiNote/src/net/micode/notes/data/Contact.java @@ -25,28 +25,34 @@ import android.util.Log; import java.util.HashMap; -public class Contact { +public class Contact { //联系人 private static HashMap sContactCache; private static final String TAG = "Contact"; - private static final String CALLER_ID_SELECTION = "PHONE_NUMBERS_EQUAL(" + Phone.NUMBER - + ",?) AND " + Data.MIMETYPE + "='" + Phone.CONTENT_ITEM_TYPE + "'" - + " AND " + Data.RAW_CONTACT_ID + " IN " + // 定义字符串CALLER_ID_SELECTION + private static final String CALLER_ID_SELECTION = "PHONE_NUMBERS_EQUAL(" + + + Phone.NUMBER + + ",?) AND " + Data.MIMETYPE + "='" + Phone.CONTENT_ITEM_TYPE + "'" + + " AND " + Data.RAW_CONTACT_ID + " IN " + "(SELECT raw_contact_id " + " FROM phone_lookup" + " WHERE min_match = '+')"; + // 获取联系人 public static String getContact(Context context, String phoneNumber) { if(sContactCache == null) { sContactCache = new HashMap(); } + // 查找HashMap中是否已有phoneNumber信息 if(sContactCache.containsKey(phoneNumber)) { return sContactCache.get(phoneNumber); } String selection = CALLER_ID_SELECTION.replace("+", PhoneNumberUtils.toCallerIDMinMatch(phoneNumber)); + // 查找数据库中phoneNumber的信息 Cursor cursor = context.getContentResolver().query( Data.CONTENT_URI, new String [] { Phone.DISPLAY_NAME }, @@ -54,17 +60,22 @@ public class Contact { new String[] { phoneNumber }, null); + // 判定查询结果 + // moveToFirst()返回第一条 if (cursor != null && cursor.moveToFirst()) { try { + // 找到相关信息 String name = cursor.getString(0); sContactCache.put(phoneNumber, name); return name; + // 异常 } catch (IndexOutOfBoundsException e) { Log.e(TAG, " Cursor get string error " + e.toString()); return null; } finally { cursor.close(); } + // 未找到相关信息 } else { Log.d(TAG, "No contact matched with number:" + phoneNumber); return null; diff --git a/MiNote/src/net/micode/notes/data/Notes.java b/MiNote/src/net/micode/notes/data/Notes.java index f240604..0925b19 100644 --- a/MiNote/src/net/micode/notes/data/Notes.java +++ b/MiNote/src/net/micode/notes/data/Notes.java @@ -17,12 +17,19 @@ package net.micode.notes.data; import android.net.Uri; + +// Notes 类中定义了很多常量，这些常量大多是int型和string型 public class Notes { public static final String AUTHORITY = "micode_notes"; public static final String TAG = "Notes"; - public static final int TYPE_NOTE = 0; - public static final int TYPE_FOLDER = 1; - public static final int TYPE_SYSTEM = 2; + //以下三个常量对NoteColumns.TYPE的值进行设置时会用到 + /** + * 帖子类型常量 + */ + public static final int TYPE_NOTE = 0; // 笔记类型 + public static final int TYPE_FOLDER = 1; // 文件夹类型 + public static final int TYPE_SYSTEM = 2; // 系统类型 + /** * Following IDs are system folders' identifiers @@ -30,21 +37,28 @@ public class Notes { * {@link Notes#ID_TEMPARAY_FOLDER } is for notes belonging no folder * {@link Notes#ID_CALL_RECORD_FOLDER} is to store call records */ - public static final int ID_ROOT_FOLDER = 0; - public static final int ID_TEMPARAY_FOLDER = -1; - public static final int ID_CALL_RECORD_FOLDER = -2; - public static final int ID_TRASH_FOLER = -3; - - public static final String INTENT_EXTRA_ALERT_DATE = "net.micode.notes.alert_date"; - public static final String INTENT_EXTRA_BACKGROUND_ID = "net.micode.notes.background_color_id"; - public static final String INTENT_EXTRA_WIDGET_ID = "net.micode.notes.widget_id"; - public static final String INTENT_EXTRA_WIDGET_TYPE = "net.micode.notes.widget_type"; - public static final String INTENT_EXTRA_FOLDER_ID = "net.micode.notes.folder_id"; - public static final String INTENT_EXTRA_CALL_DATE = "net.micode.notes.call_date"; - - public static final int TYPE_WIDGET_INVALIDE = -1; - public static final int TYPE_WIDGET_2X = 0; - public static final int TYPE_WIDGET_4X = 1; + /** + * 笔记文件夹相关的常量 + */ + public static final int ID_ROOT_FOLDER = 0; // 根文件夹的ID + public static final int ID_TEMPARAY_FOLDER = -1; // 临时文件夹的ID + public static final int ID_CALL_RECORD_FOLDER = -2; // 通话记录文件夹的ID + public static final int ID_TRASH_FOLER = -3; // 垃圾箱文件夹的ID + + /** + * 其他常量 + */ + public static final String INTENT_EXTRA_ALERT_DATE = "net.micode.notes.alert_date"; // 通知日期的额外意图值 + public static final String INTENT_EXTRA_BACKGROUND_ID = "net.micode.notes.background_color_id"; // 背景颜色ID的额外意图值 + public static final String INTENT_EXTRA_WIDGET_ID = "net.micode.notes.widget_id"; // 小部件ID的额外意图值 + public static final String INTENT_EXTRA_WIDGET_TYPE = "net.micode.notes.widget_type"; // 小部件类型的额外意图值 + public static final String INTENT_EXTRA_FOLDER_ID = "net.micode.notes.folder_id"; // 文件夹ID的额外意图值 + public static final String INTENT_EXTRA_CALL_DATE = "net.micode.notes.call_date"; // 通话日期的额外意图值 + + public static final int TYPE_WIDGET_INVALIDE = -1; // 无效的控件类型 + public static final int TYPE_WIDGET_2X = 0; // 2倍尺寸控件 + public static final int TYPE_WIDGET_4X = 1; // 4倍尺寸控件 + public static class DataConstants { public static final String NOTE = TextNote.CONTENT_ITEM_TYPE; @@ -54,13 +68,16 @@ public class Notes { /** * Uri to query all notes and folders */ + //定义查询便签和文件夹的指针 public static final Uri CONTENT_NOTE_URI = Uri.parse("content://" + AUTHORITY + "/note"); + /** * Uri to query data */ + //定义查找数据的指针。 public static final Uri CONTENT_DATA_URI = Uri.parse("content://" + AUTHORITY + "/data"); - + // 定义NoteColumns的常量,用于后面创建数据库的表头 public interface NoteColumns { /** * The unique ID for a row @@ -165,8 +182,9 @@ public class Notes { *

Type : INTEGER (long)

*/ public static final String VERSION = "version"; + //这些常量主要是定义便签的属性的。 } - + // 定义DataColumns的常量,用于后面创建数据库的表头 public interface DataColumns { /** * The unique ID for a row @@ -239,6 +257,7 @@ public class Notes { *

Type: TEXT

*/ public static final String DATA5 = "data5"; + //主要是定义存储便签内容数据的 } public static final class TextNote implements DataColumns { @@ -255,6 +274,7 @@ public class Notes { public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/text_note"; public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/text_note"); + //文本内容的数据结构 } public static final class CallNote implements DataColumns { @@ -275,5 +295,6 @@ public class Notes { public static final String CONTENT_ITEM_TYPE = "vnd.android.cursor.item/call_note"; public static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/call_note"); + //电话内容的数据结构 } } diff --git a/MiNote/src/net/micode/notes/data/NotesDatabaseHelper.java b/MiNote/src/net/micode/notes/data/NotesDatabaseHelper.java index ffe5d57..adb427a 100644 --- a/MiNote/src/net/micode/notes/data/NotesDatabaseHelper.java +++ b/MiNote/src/net/micode/notes/data/NotesDatabaseHelper.java @@ -15,24 +15,35 @@ */ package net.micode.notes.data; - +//就是用于保存一些数据（string boolean byte double float int long short ...）信息，这些信息可以被数据库操作时使用。 import android.content.ContentValues; +//加载和访问资源。 import android.content.Context; +//主要提供了对应于添加、删除、更新、查询的操作方法： insert()、delete()、update()和query()。配合content.values import android.database.sqlite.SQLiteDatabase; +//用来管理数据的创建和版本更新 import android.database.sqlite.SQLiteOpenHelper; import android.util.Log; import net.micode.notes.data.Notes.DataColumns; import net.micode.notes.data.Notes.DataConstants; import net.micode.notes.data.Notes.NoteColumns; +//数据库操作，用SQLOpenhelper,对一些note和文件进行数据库的操作，比如删除文件后，将文件里的note也相应删除 + public class NotesDatabaseHelper extends SQLiteOpenHelper { - private static final String DB_NAME = "note.db"; + private static final String DB_NAME = "note.db"; + /** + * 数据库版本号 + */ private static final int DB_VERSION = 4; - public interface TABLE { + /** + * 表名常量 + */ + public interface TABLE { //接口，分成note和data，在后面的程序里分别使用过 public static final String NOTE = "note"; public static final String DATA = "data"; @@ -42,6 +53,9 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { private static NotesDatabaseHelper mInstance; + /** + * 创建NOTE表的SQL语句 + */ private static final String CREATE_NOTE_TABLE_SQL = "CREATE TABLE " + TABLE.NOTE + "(" + NoteColumns.ID + " INTEGER PRIMARY KEY," + @@ -61,7 +75,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { NoteColumns.ORIGIN_PARENT_ID + " INTEGER NOT NULL DEFAULT 0," + NoteColumns.GTASK_ID + " TEXT NOT NULL DEFAULT ''," + NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0" + - ")"; + ")"; //数据库中需要存储的项目的名称，就相当于创建一个表格的表头的内容。 private static final String CREATE_DATA_TABLE_SQL = "CREATE TABLE " + TABLE.DATA + "(" + @@ -76,7 +90,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { DataColumns.DATA3 + " TEXT NOT NULL DEFAULT ''," + DataColumns.DATA4 + " TEXT NOT NULL DEFAULT ''," + DataColumns.DATA5 + " TEXT NOT NULL DEFAULT ''" + - ")"; + ")"; //和上面的功能一样，主要是存储的项目不同 private static final String CREATE_DATA_NOTE_ID_INDEX_SQL = "CREATE INDEX IF NOT EXISTS note_id_index ON " + @@ -92,7 +106,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { " UPDATE " + TABLE.NOTE + " SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" + " WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" + - " END"; + " END"; //在文件夹中移入一个Note之后需要更改的数据的表格。 /** * Decrease folder's note count when move note from folder @@ -105,7 +119,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { " SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" + " WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID + " AND " + NoteColumns.NOTES_COUNT + ">0" + ";" + - " END"; + " END"; //在文件夹中移出一个Note之后需要更改的数据的表格。 /** * Increase folder's note count when insert new note to the folder @@ -117,7 +131,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { " UPDATE " + TABLE.NOTE + " SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + " + 1" + " WHERE " + NoteColumns.ID + "=new." + NoteColumns.PARENT_ID + ";" + - " END"; + " END"; //在文件夹中插入一个Note之后需要更改的数据的表格。 /** * Decrease folder's note count when delete note from the folder @@ -130,7 +144,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { " SET " + NoteColumns.NOTES_COUNT + "=" + NoteColumns.NOTES_COUNT + "-1" + " WHERE " + NoteColumns.ID + "=old." + NoteColumns.PARENT_ID + " AND " + NoteColumns.NOTES_COUNT + ">0;" + - " END"; + " END"; //在文件夹中删除一个Note之后需要更改的数据的表格。 /** * Update note's content when insert data with type {@link DataConstants#NOTE} @@ -143,7 +157,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { " UPDATE " + TABLE.NOTE + " SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT + " WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" + - " END"; + " END"; //在文件夹中对一个Note导入新的数据之后需要更改的数据的表格。 /** * Update note's content when data with {@link DataConstants#NOTE} type has changed @@ -156,7 +170,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { " UPDATE " + TABLE.NOTE + " SET " + NoteColumns.SNIPPET + "=new." + DataColumns.CONTENT + " WHERE " + NoteColumns.ID + "=new." + DataColumns.NOTE_ID + ";" + - " END"; + " END"; //Note数据被修改后需要更改的数据的表格。 /** * Update note's content when data with {@link DataConstants#NOTE} type has deleted @@ -169,7 +183,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { " UPDATE " + TABLE.NOTE + " SET " + NoteColumns.SNIPPET + "=''" + " WHERE " + NoteColumns.ID + "=old." + DataColumns.NOTE_ID + ";" + - " END"; + " END"; //Note数据被删除后需要更改的数据的表格。 /** * Delete datas belong to note which has been deleted @@ -180,7 +194,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { " BEGIN" + " DELETE FROM " + TABLE.DATA + " WHERE " + DataColumns.NOTE_ID + "=old." + NoteColumns.ID + ";" + - " END"; + " END"; //删除已删除的便签的数据后需要更改的数据的表格。 /** * Delete notes belong to folder which has been deleted @@ -191,7 +205,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { " BEGIN" + " DELETE FROM " + TABLE.NOTE + " WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" + - " END"; + " END"; //删除已删除的文件夹的便签后需要更改的数据的表格。 /** * Move notes belong to folder which has been moved to trash folder @@ -204,18 +218,18 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { " UPDATE " + TABLE.NOTE + " SET " + NoteColumns.PARENT_ID + "=" + Notes.ID_TRASH_FOLER + " WHERE " + NoteColumns.PARENT_ID + "=old." + NoteColumns.ID + ";" + - " END"; + " END"; //还原垃圾桶中便签后需要更改的数据的表格。 public NotesDatabaseHelper(Context context) { super(context, DB_NAME, null, DB_VERSION); } - + //构造函数，传入数据库的名称和版本 public void createNoteTable(SQLiteDatabase db) { db.execSQL(CREATE_NOTE_TABLE_SQL); reCreateNoteTableTriggers(db); createSystemFolder(db); Log.d(TAG, "note table has been created"); - } + } //创建表格（用来存储标签属性） private void reCreateNoteTableTriggers(SQLiteDatabase db) { db.execSQL("DROP TRIGGER IF EXISTS increase_folder_count_on_update"); @@ -234,6 +248,8 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { db.execSQL(FOLDER_DELETE_NOTES_ON_DELETE_TRIGGER); db.execSQL(FOLDER_MOVE_NOTES_ON_TRASH_TRIGGER); } + //execSQL是数据库操作的API，主要是更改行为的SQL语句。 + //在这里主要是用来重新创建上述定义的表格用的，先删除原来有的数据库的触发器再重新创建新的数据库 private void createSystemFolder(SQLiteDatabase db) { ContentValues values = new ContentValues(); @@ -268,14 +284,14 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER); values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM); db.insert(TABLE.NOTE, null, values); - } + }//创建几个系统文件夹 public void createDataTable(SQLiteDatabase db) { db.execSQL(CREATE_DATA_TABLE_SQL); reCreateDataTableTriggers(db); db.execSQL(CREATE_DATA_NOTE_ID_INDEX_SQL); Log.d(TAG, "data table has been created"); - } + }//创建表格（用来存储标签内容） private void reCreateDataTableTriggers(SQLiteDatabase db) { db.execSQL("DROP TRIGGER IF EXISTS update_note_content_on_insert"); @@ -285,20 +301,23 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_INSERT_TRIGGER); db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_UPDATE_TRIGGER); db.execSQL(DATA_UPDATE_NOTE_CONTENT_ON_DELETE_TRIGGER); - } + } //同上面的execSQL static synchronized NotesDatabaseHelper getInstance(Context context) { if (mInstance == null) { mInstance = new NotesDatabaseHelper(context); } return mInstance; - } + }//解决同一时刻只能有一个线程执行. + //在写程序库代码时，有时有一个类需要被所有的其它类使用， + //但又要求这个类只能被实例化一次，是个服务类，定义一次，其它类使用同一个这个类的实例 @Override public void onCreate(SQLiteDatabase db) { createNoteTable(db); createDataTable(db); } + //实现两个表格（上面创建的两个表格） @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { @@ -331,6 +350,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { throw new IllegalStateException("Upgrade notes database to version " + newVersion + "fails"); } + //数据库版本的更新（数据库内容的更改） } private void upgradeToV2(SQLiteDatabase db) { @@ -338,6 +358,7 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { db.execSQL("DROP TABLE IF EXISTS " + TABLE.DATA); createNoteTable(db); createDataTable(db); + //更新到V2版本 } private void upgradeToV3(SQLiteDatabase db) { @@ -353,10 +374,12 @@ public class NotesDatabaseHelper extends SQLiteOpenHelper { values.put(NoteColumns.ID, Notes.ID_TRASH_FOLER); values.put(NoteColumns.TYPE, Notes.TYPE_SYSTEM); db.insert(TABLE.NOTE, null, values); + //更新到V3版本 } private void upgradeToV4(SQLiteDatabase db) { db.execSQL("ALTER TABLE " + TABLE.NOTE + " ADD COLUMN " + NoteColumns.VERSION + " INTEGER NOT NULL DEFAULT 0"); } + //更新到V4版本 } diff --git a/MiNote/src/net/micode/notes/data/NotesProvider.java b/MiNote/src/net/micode/notes/data/NotesProvider.java index edb0a60..36a5241 100644 --- a/MiNote/src/net/micode/notes/data/NotesProvider.java +++ b/MiNote/src/net/micode/notes/data/NotesProvider.java @@ -33,9 +33,17 @@ import net.micode.notes.R; import net.micode.notes.data.Notes.DataColumns; import net.micode.notes.data.Notes.NoteColumns; import net.micode.notes.data.NotesDatabaseHelper.TABLE; +//为存储和获取数据提供接口。可以在不同的应用程序之间共享数据 +//ContentProvider提供的方法 +//query：查询 +//insert：插入 +//update：更新 +//delete：删除 +//getType：得到数据类型 public class NotesProvider extends ContentProvider { + // UriMatcher用于匹配Uri private static final UriMatcher mMatcher; private NotesDatabaseHelper mHelper; @@ -51,7 +59,10 @@ public class NotesProvider extends ContentProvider { private static final int URI_SEARCH_SUGGEST = 6; static { + // 创建UriMatcher时，调用UriMatcher(UriMatcher.NO_MATCH)表示不匹配任何路径的返回码 + mMatcher = new UriMatcher(UriMatcher.NO_MATCH); + // 把需要匹配Uri路径全部给注册上 mMatcher.addURI(Notes.AUTHORITY, "note", URI_NOTE); mMatcher.addURI(Notes.AUTHORITY, "note/#", URI_NOTE_ITEM); mMatcher.addURI(Notes.AUTHORITY, "data", URI_DATA); @@ -65,6 +76,7 @@ public class NotesProvider extends ContentProvider { * x'0A' represents the '\n' character in sqlite. For title and content in the search result, * we will trim '\n' and white space in order to show more information. */ + // 声明 NOTES_SEARCH_PROJECTION private static final String NOTES_SEARCH_PROJECTION = NoteColumns.ID + "," + NoteColumns.ID + " AS " + SearchManager.SUGGEST_COLUMN_INTENT_EXTRA_DATA + "," + "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_1 + "," @@ -72,7 +84,7 @@ public class NotesProvider extends ContentProvider { + R.drawable.search_result + " AS " + SearchManager.SUGGEST_COLUMN_ICON_1 + "," + "'" + Intent.ACTION_VIEW + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_ACTION + "," + "'" + Notes.TextNote.CONTENT_TYPE + "' AS " + SearchManager.SUGGEST_COLUMN_INTENT_DATA; - + // 声明NOTES_SNIPPET_SEARCH_QUERY private static String NOTES_SNIPPET_SEARCH_QUERY = "SELECT " + NOTES_SEARCH_PROJECTION + " FROM " + TABLE.NOTE + " WHERE " + NoteColumns.SNIPPET + " LIKE ?" @@ -80,18 +92,24 @@ public class NotesProvider extends ContentProvider { + " AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE; @Override + // Context只有在onCreate()中才被初始化 + // 对mHelper进行实例化 public boolean onCreate() { mHelper = NotesDatabaseHelper.getInstance(getContext()); return true; } @Override + // 查询uri在数据库中对应的位置 public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) { Cursor c = null; + // 获取可读数据库 SQLiteDatabase db = mHelper.getReadableDatabase(); String id = null; + // 匹配查找uri switch (mMatcher.match(uri)) { + // 对于不同的匹配值，在数据库中查找相应的条目 case URI_NOTE: c = db.query(TABLE.NOTE, projection, selection, selectionArgs, null, null, sortOrder); @@ -113,6 +131,7 @@ public class NotesProvider extends ContentProvider { case URI_SEARCH: case URI_SEARCH_SUGGEST: if (sortOrder != null || projection != null) { + // 不合法的参数异常 throw new IllegalArgumentException( "do not specify sortOrder, selection, selectionArgs, or projection" + "with this query"); } @@ -120,6 +139,8 @@ public class NotesProvider extends ContentProvider { String searchString = null; if (mMatcher.match(uri) == URI_SEARCH_SUGGEST) { if (uri.getPathSegments().size() > 1) { + // getPathSegments()方法得到一个String的List， + // 在uri.getPathSegments().get(1)为第2个元素 searchString = uri.getPathSegments().get(1); } } else { @@ -139,6 +160,7 @@ public class NotesProvider extends ContentProvider { } break; default: + // 抛出异常 throw new IllegalArgumentException("Unknown URI " + uri); } if (c != null) { @@ -148,13 +170,17 @@ public class NotesProvider extends ContentProvider { } @Override + // 插入一个uri public Uri insert(Uri uri, ContentValues values) { + // 获得可写的数据库 SQLiteDatabase db = mHelper.getWritableDatabase(); long dataId = 0, noteId = 0, insertedId = 0; switch (mMatcher.match(uri)) { + // 新增一个条目 case URI_NOTE: insertedId = noteId = db.insert(TABLE.NOTE, null, values); break; + // 如果存在，查找NOTE_ID case URI_DATA: if (values.containsKey(DataColumns.NOTE_ID)) { noteId = values.getAsLong(DataColumns.NOTE_ID); @@ -165,6 +191,8 @@ public class NotesProvider extends ContentProvider { break; default: throw new IllegalArgumentException("Unknown URI " + uri); + // Notify the note uri + // notifyChange获得一个ContextResolver对象并且更新里面的内容 } // Notify the note uri if (noteId > 0) { @@ -177,14 +205,19 @@ public class NotesProvider extends ContentProvider { getContext().getContentResolver().notifyChange( ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId), null); } - + // 返回插入的uri的路径 return ContentUris.withAppendedId(uri, insertedId); } @Override + // 删除一个uri public int delete(Uri uri, String selection, String[] selectionArgs) { + //Uri代表要操作的数据，Android上可用的每种资源 -包括 图像、视频片段、音频资源等都可以用Uri来表示。 + int count = 0; String id = null; + // 获得可写的数据库 + SQLiteDatabase db = mHelper.getWritableDatabase(); boolean deleteData = false; switch (mMatcher.match(uri)) { @@ -228,6 +261,8 @@ public class NotesProvider extends ContentProvider { } @Override + // 更新一个uri + public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) { int count = 0; String id = null; @@ -267,11 +302,13 @@ public class NotesProvider extends ContentProvider { return count; } - private String parseSelection(String selection) { + private String parseSelection(String selection) { // 将字符串解析成规定格式 + return (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : ""); } private void increaseNoteVersion(long id, String selection, String[] selectionArgs) { + //增加一个noteVersion StringBuilder sql = new StringBuilder(120); sql.append("UPDATE "); sql.append(TABLE.NOTE); @@ -292,12 +329,13 @@ public class NotesProvider extends ContentProvider { } sql.append(selectString); } - + // execSQL()方法可以执行insert、delete、update和CREATE TABLE之类有更改行为的SQL语句 mHelper.getWritableDatabase().execSQL(sql.toString()); } @Override public String getType(Uri uri) { + // TODO Auto-generated method stub return null; }