一、NoteList中显示条目增加时间戳显示

过程及重要代码

要增加时间戳，首先要获取当前时间，北京时间要用GMT时间加八小时得到（这里是创建Note时获取的时间）

 Date date = new Date(now);     SimpleDateFormat format = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");     format.setTimeZone(TimeZone.getTimeZone("GMT+08:00"));     String formatDate = format.format(date); 

原程序已经在数据库SQLite定义好了时间变量，所以可以把获取到的时间赋值给时间变量

 if (values.containsKey(NotePad.Notes.COLUMN_NAME_CREATE_DATE) == false) {             values.put(NotePad.Notes.COLUMN_NAME_CREATE_DATE, formatDate); } if (values.containsKey(NotePad.Notes.COLUMN_NAME_MODIFICATION_DATE) == false) {         values.put(NotePad.Notes.COLUMN_NAME_MODIFICATION_DATE, formatDate); } 

时间戳是显示在每条Note的下面，所以在noteslist_item.xml添加一个用于显示时间戳的TextView

 <TextView         android:id="@+id/text1_date"         android:layout_width="match_parent"         android:layout_height="match_parent"         android:textSize="17dp"         android:paddingLeft="5dip" /> 

接着在它的java文件NoteList.java中关于显示Note的函数里加上时间的显示

 private static final String[] PROJECTION = new String[] {             NotePad.Notes._ID, // 0             NotePad.Notes.COLUMN_NAME_TITLE, // 1             NotePad.Notes.COLUMN_NAME_MODIFICATION_DATE //日期 }; private static final int COLUMN_INDEX_TITLE = 1; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setDefaultKeyMode(DEFAULT_KEYS_SHORTCUT);         Intent intent = getIntent(); if (intent.getData() == null) {             intent.setData(NotePad.Notes.CONTENT_URI); } getListView().setOnCreateContextMenuListener(this);         Cursor cursor = managedQuery( getIntent().getData(), // Use the default content URI for the provider.             PROJECTION, // Return the note ID and title for each note.             null, // No where clause, return all records.             null, // No where clause, therefore no where column values.             NotePad.Notes.DEFAULT_SORT_ORDER  // Use the default sort order. );         String[] dataColumns = {                 NotePad.Notes.COLUMN_NAME_TITLE,                 NotePad.Notes.COLUMN_NAME_MODIFICATION_DATE         } ; int[] viewIDs = {                 android.R.id.text1,                 R.id.text1_date         };         SimpleCursorAdapter adapter             = new SimpleCursorAdapter( this, // The Context for the ListView                       R.layout.noteslist_item, // Points to the XML for a list item                       cursor, // The cursor to get items from                       dataColumns,                       viewIDs               ); setListAdapter(adapter); } 

注意，还要在NoteEditor.java里也添加获取时间的功能（这里是编辑Note时获取的时间），不然无法正确显示编辑Note后的时间

效果截图

二、添加笔记查询功能（根据标题查询）

过程及重要代码

先在顶部的菜单栏中添加查找的图标,这里用的是Android Studio自带图标库里的ic_menu_search

代码：

 <item         android:id="@+id/menu_search"         android:icon="@android:drawable/ic_menu_search"         android:title="Search"         app:showAsAction="always" /> 

再新建一个Activity——NoteSearch,用于查找功能的布局和功能实现
布局样式：

代码：

 <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="https://schemas.android.com/apk/res/android"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:orientation="vertical"> <SearchView         android:id="@+id/search_view"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:iconifiedByDefault="false" /> <ListView         android:id="@+id/list_view"         android:layout_width="match_parent"         android:layout_height="wrap_content" /> </LinearLayout> 

接着在菜单栏java文件的switch选择中，添加查找功能的case

 case R.id.menu_search: /*                 查找功能              */             Intent intent = new Intent(this, NoteSearch.class); this.startActivity(intent); return true; 

然后在NoteSearch.java里完成查找功能的实现
原理：在用Cursor获取数据库的数据时，添加SearchView里的查找条件selection

 public boolean onQueryTextChange(String string) {     String selection1 = NotePad.Notes.COLUMN_NAME_TITLE+" like ? or "+NotePad.Notes.COLUMN_NAME_NOTE+" like ?";     String[] selection2 = {"%"+string+"%","%"+string+"%"};     Cursor cursor = sqLiteDatabase.query(                 NotePad.Notes.TABLE_NAME,                 PROJECTION, // The columns to return from the query                 selection1, // The columns for the where clause                 selection2, // The values for the where clause                 null, // don't group the rows                 null, // don't filter by row groups                 NotePad.Notes.DEFAULT_SORT_ORDER // The sort order ); 

剩下的显示功能，用原来NoteList的显示代码即可完成

 // The names of the cursor columns to display in the view, initialized to the title column         String[] dataColumns = {                 NotePad.Notes.COLUMN_NAME_TITLE,                 NotePad.Notes.COLUMN_NAME_MODIFICATION_DATE         } ; // The view IDs that will display the cursor columns, initialized to the TextView in // noteslist_item.xml int[] viewIDs = {                 android.R.id.text1,                 R.id.text1_date         }; // Creates the backing adapter for the ListView.         SimpleCursorAdapter adapter                 = new SimpleCursorAdapter( this, // The Context for the ListView                 R.layout.noteslist_item, // Points to the XML for a list item                 cursor, // The cursor to get items from                 dataColumns,                 viewIDs         ); // Sets the ListView's adapter to be the cursor adapter that was just created.         listView.setAdapter(adapter); return true; } 

onCreate也基本沿用了原来NoteList.java的实现代码

 ListView listView;     SQLiteDatabase sqLiteDatabase; /**      * The columns needed by the cursor adapter      */ private static final String[] PROJECTION = new String[]{             NotePad.Notes._ID, // 0             NotePad.Notes.COLUMN_NAME_TITLE, // 1             NotePad.Notes.COLUMN_NAME_MODIFICATION_DATE//时间 }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.note_search);         SearchView searchView = findViewById(R.id.search_view);         Intent intent = getIntent(); if (intent.getData() == null) {             intent.setData(NotePad.Notes.CONTENT_URI); }         listView = findViewById(R.id.list_view);         sqLiteDatabase = new NotePadProvider.DatabaseHelper(this).getReadableDatabase();         searchView.setOnQueryTextListener(this); } 

效果截图