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data/NotesProvider.java注释

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何思源 4 months ago
parent 83e1d1c34a
commit c79ad0f2ea
1 changed files with 51 additions and 33 deletions
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app/src/main/java/net/micode/notes/data/NotesProvider.java
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@ -35,21 +35,24 @@ import net.micode.notes.data.Notes.NoteColumns;
import net.micode.notes.data.NotesDatabaseHelper.TABLE;
// 笔记内容提供者，继承ContentProvider，管理数据的增删改查
public class NotesProvider extends ContentProvider {
// URI匹配器，用于匹配不同的URI请求
private static final UriMatcher mMatcher;
// 数据库帮助类实例
private NotesDatabaseHelper mHelper;
// 日志标签
private static final String TAG = "NotesProvider";
private static final int URI_NOTE = 1;
private static final int URI_NOTE_ITEM = 2;
private static final int URI_DATA = 3;
private static final int URI_DATA_ITEM = 4;
private static final int URI_SEARCH = 5;
private static final int URI_SEARCH_SUGGEST = 6;
// URI匹配码定义
private static final int URI_NOTE = 1; // 笔记集合URI
private static final int URI_NOTE_ITEM = 2; // 单个笔记URI
private static final int URI_DATA = 3; // 数据集合URI
private static final int URI_DATA_ITEM = 4; // 单个数据URI
private static final int URI_SEARCH = 5; // 搜索URI
private static final int URI_SEARCH_SUGGEST = 6; // 搜索建议URI
// 静态代码块，初始化URI匹配器
static {
mMatcher = new UriMatcher(UriMatcher.NO_MATCH);
mMatcher.addURI(Notes.AUTHORITY, "note", URI_NOTE);
@ -62,39 +65,42 @@ 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.
* 搜索投影定义，用于搜索结果的列定义
* x'0A'代表SQLite中的换行符，搜索时会替换和修剪换行符
*/
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 + ","
+ "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_2 + ","
+ 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;
+ NoteColumns.ID + " AS " + SearchManager.SUGGEST_COLUMN_INTENT_EXTRA_DATA + ","
+ "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_1 + ","
+ "TRIM(REPLACE(" + NoteColumns.SNIPPET + ", x'0A','')) AS " + SearchManager.SUGGEST_COLUMN_TEXT_2 + ","
+ 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;
// 笔记内容搜索查询语句
private static String NOTES_SNIPPET_SEARCH_QUERY = "SELECT " + NOTES_SEARCH_PROJECTION
+ " FROM " + TABLE.NOTE
+ " WHERE " + NoteColumns.SNIPPET + " LIKE ?"
+ " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER
+ " AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE;
+ " FROM " + TABLE.NOTE
+ " WHERE " + NoteColumns.SNIPPET + " LIKE ?"
+ " AND " + NoteColumns.PARENT_ID + "<>" + Notes.ID_TRASH_FOLER
+ " AND " + NoteColumns.TYPE + "=" + Notes.TYPE_NOTE;
// 初始化内容提供者，获取数据库帮助类实例
@Override
public boolean onCreate() {
mHelper = NotesDatabaseHelper.getInstance(getContext());
return true;
}
// 处理数据查询请求
@Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
String sortOrder) {
String sortOrder) {
Cursor c = null;
SQLiteDatabase db = mHelper.getReadableDatabase();
String id = null;
// 根据URI匹配码执行不同的查询操作
switch (mMatcher.match(uri)) {
case URI_NOTE:
c = db.query(TABLE.NOTE, projection, selection, selectionArgs, null, null,
sortOrder);
c = db.query(TABLE.NOTE, projection, selection, selectionArgs, null, null, sortOrder);
break;
case URI_NOTE_ITEM:
id = uri.getPathSegments().get(1);
@ -102,8 +108,7 @@ public class NotesProvider extends ContentProvider {
+ parseSelection(selection), selectionArgs, null, null, sortOrder);
break;
case URI_DATA:
c = db.query(TABLE.DATA, projection, selection, selectionArgs, null, null,
sortOrder);
c = db.query(TABLE.DATA, projection, selection, selectionArgs, null, null, sortOrder);
break;
case URI_DATA_ITEM:
id = uri.getPathSegments().get(1);
@ -112,12 +117,14 @@ public class NotesProvider extends ContentProvider {
break;
case URI_SEARCH:
case URI_SEARCH_SUGGEST:
// 搜索请求不允许指定排序和投影
if (sortOrder != null || projection != null) {
throw new IllegalArgumentException(
"do not specify sortOrder, selection, selectionArgs, or projection" + "with this query");
}
String searchString = null;
// 从URI中获取搜索字符串
if (mMatcher.match(uri) == URI_SEARCH_SUGGEST) {
if (uri.getPathSegments().size() > 1) {
searchString = uri.getPathSegments().get(1);
@ -131,6 +138,7 @@ public class NotesProvider extends ContentProvider {
}
try {
// 构造模糊查询字符串
searchString = String.format("%%%s%%", searchString);
c = db.rawQuery(NOTES_SNIPPET_SEARCH_QUERY,
new String[] { searchString });
@ -141,21 +149,25 @@ public class NotesProvider extends ContentProvider {
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
// 设置查询结果的通知URI
if (c != null) {
c.setNotificationUri(getContext().getContentResolver(), uri);
}
return c;
}
// 处理数据插入请求
@Override
public Uri insert(Uri uri, ContentValues values) {
SQLiteDatabase db = mHelper.getWritableDatabase();
long dataId = 0, noteId = 0, insertedId = 0;
// 根据URI匹配码执行不同的插入操作
switch (mMatcher.match(uri)) {
case URI_NOTE:
insertedId = noteId = db.insert(TABLE.NOTE, null, values);
break;
case URI_DATA:
// 数据插入需要关联笔记ID
if (values.containsKey(DataColumns.NOTE_ID)) {
noteId = values.getAsLong(DataColumns.NOTE_ID);
} else {
@ -166,13 +178,12 @@ public class NotesProvider extends ContentProvider {
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
// Notify the note uri
// 通知内容变更
if (noteId > 0) {
getContext().getContentResolver().notifyChange(
ContentUris.withAppendedId(Notes.CONTENT_NOTE_URI, noteId), null);
}
// Notify the data uri
if (dataId > 0) {
getContext().getContentResolver().notifyChange(
ContentUris.withAppendedId(Notes.CONTENT_DATA_URI, dataId), null);
@ -181,12 +192,14 @@ public class NotesProvider extends ContentProvider {
return ContentUris.withAppendedId(uri, insertedId);
}
// 处理数据删除请求
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
int count = 0;
String id = null;
SQLiteDatabase db = mHelper.getWritableDatabase();
boolean deleteData = false;
// 根据URI匹配码执行不同的删除操作
switch (mMatcher.match(uri)) {
case URI_NOTE:
selection = "(" + selection + ") AND " + NoteColumns.ID + ">0 ";
@ -194,10 +207,7 @@ public class NotesProvider extends ContentProvider {
break;
case URI_NOTE_ITEM:
id = uri.getPathSegments().get(1);
/**
* ID that smaller than 0 is system folder which is not allowed to
* trash
*/
// 系统文件夹不允许删除
long noteId = Long.valueOf(id);
if (noteId <= 0) {
break;
@ -218,6 +228,7 @@ public class NotesProvider extends ContentProvider {
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
// 通知内容变更
if (count > 0) {
if (deleteData) {
getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
@ -227,12 +238,14 @@ public class NotesProvider extends ContentProvider {
return count;
}
// 处理数据更新请求
@Override
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
int count = 0;
String id = null;
SQLiteDatabase db = mHelper.getWritableDatabase();
boolean updateData = false;
// 根据URI匹配码执行不同的更新操作
switch (mMatcher.match(uri)) {
case URI_NOTE:
increaseNoteVersion(-1, selection, selectionArgs);
@ -258,6 +271,7 @@ public class NotesProvider extends ContentProvider {
throw new IllegalArgumentException("Unknown URI " + uri);
}
// 通知内容变更
if (count > 0) {
if (updateData) {
getContext().getContentResolver().notifyChange(Notes.CONTENT_NOTE_URI, null);
@ -267,10 +281,12 @@ public class NotesProvider extends ContentProvider {
return count;
}
// 解析查询条件，添加AND操作符
private String parseSelection(String selection) {
return (!TextUtils.isEmpty(selection) ? " AND (" + selection + ')' : "");
}
// 增加笔记版本号
private void increaseNoteVersion(long id, String selection, String[] selectionArgs) {
StringBuilder sql = new StringBuilder(120);
sql.append("UPDATE ");
@ -279,6 +295,7 @@ public class NotesProvider extends ContentProvider {
sql.append(NoteColumns.VERSION);
sql.append("=" + NoteColumns.VERSION + "+1 ");
// 构建更新条件
if (id > 0 || !TextUtils.isEmpty(selection)) {
sql.append(" WHERE ");
}
@ -296,10 +313,11 @@ public class NotesProvider extends ContentProvider {
mHelper.getWritableDatabase().execSQL(sql.toString());
}
// 获取URI对应的MIME类型（未实现）
@Override
public String getType(Uri uri) {
// TODO Auto-generated method stub
return null;
}
}
}
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