1excludeFromSuggestions=true
2page.title=Notepad Exercise 1
3parent.title=Notepad Tutorial
4parent.link=index.html
5@jd:body
6
7
8<p><em>In this exercise, you will construct a simple notes list that lets the
9user add new notes but not edit them. The exercise demonstrates:</em></p>
10<ul>
11<li><em>The basics of <code>ListActivities</code> and creating and handling menu
12options. </em></li>
13<li><em>How to use a SQLite database to store the notes.</em></li>
14<li><em>How to bind data from a database cursor into a ListView using a
15SimpleCursorAdapter.</em></li>
16<li><em>The basics of screen layouts, including how to lay out a list view, how
17you can add items to the activity menu, and how the activity handles those menu
18selections. </em></li>
19</ul>
20
21<div style="float:right;white-space:nowrap">
22<span style="color:#BBB;">
23	[<a href="notepad-ex1.html" style="color:#BBB;">Exercise 1</a>]</span>
24	[<a href="notepad-ex2.html">Exercise 2</a>]
25	[<a href="notepad-ex3.html">Exercise 3</a>]
26	[<a href="notepad-extra-credit.html">Extra Credit</a>]
27</div>
28
29
30
31<h2>Step 1</h2>
32
33	<p>Open up the <code>Notepadv1</code> project in Eclipse.</p>
34
35    <p><code>Notepadv1</code> is a project that is provided as a starting point. It
36    takes care of some of the boilerplate work that you have already seen if you
37    followed the <a href="{@docRoot}training/basics/firstapp/index.html">Hello,
38    World</a> tutorial.</p>
39
40  <ol>
41    <li>
42      Start a new Android Project by clicking <strong>File</strong> >
43      <strong>New</strong> > <strong>Android Project</strong>.</li>
44    <li>
45      In the New Android Project dialog, select <strong>Create project from existing source</strong>.</li>
46    <li>
47      Click <strong>Browse</strong> and navigate to where you copied the <code>NotepadCodeLab</code>
48      (downloaded during <a href="{@docRoot}training/notepad/index.html#preparing">setup</a>)
49      and select <code>Notepadv1</code>.</li>
50    <li>
51      The Project Name and other properties should be automatically filled for you.
52      You must select the Build Target&mdash;we recommend selecting a target with the
53      lowest platform version available. Also add an integer to the Min SDK Version field
54      that matches the API Level of the selected Build Target.</li>
55    <li>
56      Click <strong>Finish</strong>. The <code>Notepadv1</code> project should open and be
57      visible in your Eclipse package explorer.</li>
58  </ol>
59
60    <p>If you see an error about <code>AndroidManifest.xml</code>, or some
61      problems related to an Android zip file, right click on the project and
62      select <strong>Android Tools</strong> > <strong>Fix Project Properties</strong>.
63      (The project is looking in the wrong location for the library file,
64      this will fix it for you.)</p>
65
66  <h2>Step 2</h2>
67
68  <div class="sidebox-wrapper">
69  <div class="sidebox">
70    <h2>Accessing and modifying data</h2>
71    <p>For this
72    exercise, we are using a SQLite database to store our data. This is useful
73    if only <em>your</em> application will need to access or modify the data. If you wish for
74    other activities to access or modify the data, you have to expose the data using a
75    {@link android.content.ContentProvider ContentProvider}.</p>
76    <p>If you are interested, you can find out more about
77    <a href="{@docRoot}guide/topics/providers/content-providers.html">content providers</a> or the
78whole
79    subject of <a href="{@docRoot}guide/topics/data/data-storage.html">Data Storage</a>.
80    The NotePad sample in the <code>samples/</code> folder of the SDK also has an example of how
81    to create a ContentProvider.</p>
82  </div>
83  </div>
84
85    <p>Take a look at the <code>NotesDbAdapter</code> class &mdash; this class is provided to
86    encapsulate data access to a SQLite database that will hold our notes data
87    and allow us to update it.</p>
88    <p>At the top of the class are some constant definitions that will be used in the application
89    to look up data from the proper field names in the database. There is also a database creation
90    string defined, which is used to create a new database schema if one doesn't exist already.</p>
91    <p>Our database will have the name <code>data</code>, and have a single table called
92    <code>notes</code>, which in turn has three fields: <code>_id</code>, <code>title</code> and
93    <code>body</code>. The <code>_id</code> is named with an underscore convention used in a number of
94    places inside the Android SDK and helps keep a track of state. The <code>_id</code>
95    usually has to be specified when querying or updating the database (in the column projections
96    and so on). The other two fields are simple text fields that will store data.
97    </p>
98    <p>The constructor for <code>NotesDbAdapter</code> takes a Context, which allows it to communicate with aspects
99    of the Android operating system. This is quite common for classes that need to touch the
100    Android system in some way. The Activity class implements the Context class, so usually you will just pass
101    <code>this</code> from your Activity, when needing a Context.</p>
102    <p>The <code>open()</code> method calls up an instance of DatabaseHelper, which is our local
103    implementation of the SQLiteOpenHelper class. It calls <code>getWritableDatabase()</code>,
104    which handles creating/opening a database for us.</p>
105    <p><code>close()</code> just closes the database, releasing resources related to the
106    connection.</p>
107    <p><code>createNote()</code> takes strings for the title and body of a new note,
108    then creates that note in the database. Assuming the new note is created successfully, the
109    method also returns the row <code>_id</code> value for the newly created note.</p>
110    <p><code>deleteNote()</code> takes a <var>rowId</var> for a particular note, and deletes that note from
111    the database.</p>
112
113    <p><code>fetchAllNotes()</code> issues a query to return a {@link android.database.Cursor} over all notes in the
114    database. The <code>query()</code> call is worth examination and understanding. The first field is the
115    name of the database table to query (in this case <code>DATABASE_TABLE</code> is "notes").
116    The next is the list of columns we want returned, in this case we want the <code>_id</code>,
117    <code>title</code> and <code>body</code> columns so these are specified in the String array.
118    The remaining fields are, in order: <code>selection</code>,
119    <code>selectionArgs</code>, <code>groupBy</code>, <code>having</code> and <code>orderBy</code>.
120    Having these all <code>null</code> means we want all data, need no grouping, and will take the default
121    order. See {@link android.database.sqlite.SQLiteDatabase SQLiteDatabase} for more details.</p>
122    <p class="note"><b>Note:</b> A Cursor is returned rather than a collection of rows. This allows
123    Android to use resources efficiently -- instead of putting lots of data straight into memory
124    the cursor will retrieve and release data as it is needed, which is much more efficient for
125    tables with lots of rows.</p>
126
127    <p><code>fetchNote()</code> is similar to <code>fetchAllNotes()</code> but just gets one note
128    with the <var>rowId</var> we specify. It uses a slightly different version of the
129    {@link android.database.sqlite.SQLiteDatabase} <code>query()</code> method.
130    The first parameter (set <em>true</em>) indicates that we are interested
131    in one distinct result. The <var>selection</var> parameter (the fourth parameter) has been specified to search
132    only for the row "where _id =" the <var>rowId</var> we passed in. So we are returned a Cursor on
133    the one row.</p>
134    <p>And finally, <code>updateNote()</code> takes a <var>rowId</var>, <var>title</var> and <var>body</var>, and uses a
135    {@link android.content.ContentValues ContentValues} instance to update the note of the given
136    <var>rowId</var>.</p>
137
138<h2 style="clear:right;">Step 3</h2>
139
140	<div class="sidebox-wrapper">
141  <div class="sidebox">
142    <h2>Layouts and activities</h2>
143      <p>Most Activity classes will have a layout associated with them. The layout
144    will be the "face" of the Activity to the user. In this case our layout will
145    take over the whole screen and provide a list of notes.</p>
146    <p>Full screen layouts are not the only option for an Activity however. You
147    might also want to use a <a
148href="{@docRoot}resources/faq/commontasks.html#floatingorfull">floating
149    layout</a> (for example, a <a
150href="{@docRoot}resources/faq/commontasks.html#dialogsandalerts">dialog
151    or alert</a>),
152    or perhaps you don't need a layout at all (the Activity will be invisible
153    to the user unless you specify some kind of layout for it to use).</p>
154  </div>
155  </div>
156
157    <p>Open the <code>notepad_list.xml</code> file in <code>res/layout</code>
158and
159    take a look at it. (You may have to
160    hit the <em>xml</em> tab, at the bottom, in order to view the XML markup.)</p>
161
162    <p>This is a mostly-empty layout definition file. Here are some
163    things you should know about a layout file:</p>
164
165
166  <ul>
167    <li>
168      All Android layout files must start with the XML header line:
169      <code>&lt;?xml version="1.0" encoding="utf-8"?&gt;</code>.    </li>
170    <li>
171      The next definition will often (but not always) be a layout
172      definition of some kind, in this case a <code>LinearLayout</code>.    </li>
173    <li>
174      The XML namespace of Android should always be defined in
175      the top level component or layout in the XML so that <code>android:</code> tags can
176      be used through the rest of the file:
177      <p><code>xmlns:android="http://schemas.android.com/apk/res/android"</code></p>
178    </li>
179  </ul>
180
181  <h2 style="clear:right;">Step 4</h2>
182    <p>We need to create the layout to hold our list. Add code inside
183    of the <code>LinearLayout</code> element so the whole file looks like this: </p>
184    <pre>
185&lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
186&lt;LinearLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
187    android:layout_width=&quot;wrap_content&quot;
188    android:layout_height=&quot;wrap_content&quot;&gt;
189
190  &lt;ListView android:id=&quot;@android:id/list&quot;
191        android:layout_width=&quot;wrap_content&quot;
192        android:layout_height=&quot;wrap_content&quot;/&gt;
193  &lt;TextView android:id=&quot;@android:id/empty&quot;
194        android:layout_width=&quot;wrap_content&quot;
195        android:layout_height=&quot;wrap_content&quot;
196        android:text=&quot;@string/no_notes&quot;/&gt;
197
198&lt;/LinearLayout&gt;
199</pre>
200  <ul>
201    <li>
202      The <strong>&#64;</strong> symbol in the id strings of the <code>ListView</code> and
203      <code>TextView</code> tags means
204      that the XML parser should parse and expand the rest of
205      the id string and use an ID resource.</li>
206    <li>
207      The <code>ListView</code> and <code>TextView</code> can be
208      thought as two alternative views, only one of which will be displayed at once.
209      ListView will be used when there are notes to be shown, while the TextView
210      (which has a default value of "No Notes Yet!" defined as a string
211      resource in <code>res/values/strings.xml</code>) will be displayed if there
212      aren't any notes to display.</li>
213    <li>The <code>list</code> and <code>empty</code> IDs are
214      provided for us by the Android platform, so, we must
215      prefix the <code>id</code> with <code>android:</code> (e.g., <code>@android:id/list</code>).</li>
216    <li>The View with the <code>empty</code> id is used
217      automatically when the {@link android.widget.ListAdapter} has no data for the ListView. The
218      ListAdapter knows to look for this name by default. Alternatively, you could change the
219      default empty view by using {@link android.widget.AdapterView#setEmptyView(View)}
220      on the ListView.
221      <p>
222      More broadly, the <code>android.R</code> class is a set of predefined
223      resources provided for you by the platform, while your project's
224      <code>R</code> class is the set of resources your project has defined.
225      Resources found in the <code>android.R</code> resource class can be
226      used in the XML files by using the <code>android:</code> name space prefix
227      (as we see here).</p>
228    </li>
229  </ul>
230
231  <h2 style="clear:right;">Step 5</h2>
232
233	<div class="sidebox-wrapper">
234  <div class="sidebox">
235    <h2>Resources and the R class</h2>
236    <p>The folders under res/ in the Eclipse project are for resources.
237     There is a <a href="{@docRoot}resources/faq/commontasks.html#filelist">specific structure</a>
238to the
239     folders and files under res/.</p>
240    <p>Resources defined in these folders and files will have
241    corresponding entries in the R class allowing them to be easily accessed
242    and used from your application. The R class is automatically generated using the contents
243    of the res/ folder by the eclipse plugin (or by aapt if you use the command line tools).
244    Furthermore, they will be bundled and deployed for you as part of the application.</p>
245    </p>
246  </div>
247  </div>
248
249    <p>To make the list of notes in the ListView, we also need to define a View for each row:</p>
250  <ol>
251    <li>
252      Create a new file under <code>res/layout</code> called
253      <code>notes_row.xml</code>.    </li>
254    <li>
255      Add the following contents (note: again the XML header is used, and the
256      first node defines the Android XML namespace)<br>
257      <pre style="overflow:auto">
258&lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
259&lt;TextView android:id=&quot;&#64;+id/text1&quot;
260    xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
261    android:layout_width=&quot;wrap_content&quot;
262    android:layout_height=&quot;wrap_content&quot;/&gt;</pre>
263    <p>
264      This is the View that will be used for each notes title row &mdash; it has only
265      one text field in it.    </p>
266    <p>In this case we create a new id called <code>text1</code>. The
267      <strong>+</strong> after the <strong>@</strong> in the id string indicates that the id should
268      be automatically created as a resource if it does not already exist, so we are defining
269      <code>text1</code> on the fly and then using it.</p>
270    </li>
271    <li>Save the file.</li>
272  </ol>
273      <p>Open the <code>R.java</code> class in the
274      project and look at it, you should see new definitions for
275      <code>notes_row</code> and <code>text1</code> (our new definitions)
276      meaning we can now gain access to these from the our code. </p>
277
278  <h2 style="clear:right;">Step 6</h2>
279<p>Next, open the <code>Notepadv1</code> class in the source. In the following steps, we are going to
280    alter this class to become a list adapter and display our notes, and also
281    allow us to add new notes.</p>
282
283<p><code>Notepadv1</code> will inherit from a subclass
284    of <code>Activity</code> called a <code>ListActivity</code>,
285    which has extra functionality to accommodate the kinds of
286    things you might want to do with a list, for
287    example: displaying an arbitrary number of list items in rows on the screen,
288    moving through the list items, and allowing them to be selected.</p>
289
290<p>Take a look through the existing code in <code>Notepadv1</code> class.
291    There is a currently an unused private field called <code>mNoteNumber</code> that
292    we will use to create numbered note titles.</p>
293    <p>There are also three override methods defined:
294    <code>onCreate</code>, <code>onCreateOptionsMenu</code> and
295    <code>onOptionsItemSelected</code>; we need to fill these
296    out:</p>
297    <ul>
298      <li><code>onCreate()</code> is called when the activity is
299      started &mdash; it is a little like the "main" method for an Activity. We use
300      this to set up resources and state for the activity when it is
301      running.</li>
302     <li><code>onCreateOptionsMenu()</code> is used to populate the
303      menu for the Activity. This is shown when the user hits the menu button,
304and
305      has a list of options they can select (like "Create
306      Note"). </li>
307     <li><code>onOptionsItemSelected()</code> is the other half of the
308      menu equation, it is used to handle events generated from the menu (e.g.,
309      when the user selects the "Create Note" item).
310      </li>
311    </ul>
312
313  <h2>Step 7</h2>
314    <p>Change the inheritance of <code>Notepadv1</code> from
315<code>Activity</code>
316    to <code>ListActivity</code>:</p>
317    <pre>public class Notepadv1 extends ListActivity</pre>
318    <p>Note: you will have to import <code>ListActivity</code> into the
319Notepadv1
320    class using Eclipse, <strong>ctrl-shift-O</strong> on Windows or Linux, or
321    <strong>cmd-shift-O</strong> on the Mac (organize imports) will do this for you
322    after you've written the above change.</p>
323
324  <h2>Step 8</h2>
325    <p>Fill out the body of the <code>onCreate()</code> method.</p>
326    <p>Here we will set the title for the Activity (shown at the top of the
327    screen), use the <code>notepad_list</code> layout we created in XML,
328    set up the <code>NotesDbAdapter</code> instance that will
329    access notes data, and populate the list with the available note
330    titles:</p>
331    <ol>
332    <li>
333      In the <code>onCreate</code> method, call <code>super.onCreate()</code> with the
334      <code>savedInstanceState</code> parameter that's passed in.</li>
335    <li>
336      Call <code>setContentView()</code> and pass <code>R.layout.notepad_list</code>.</li>
337    <li>
338      At the top of the class, create a new private class field called <code>mDbHelper</code> of class
339      <code>NotesDbAdapter</code>.
340    </li>
341    <li>
342      Back in the <code>onCreate</code> method, construct a new
343<code>NotesDbAdapter</code>
344      instance and assign it to the <code>mDbHelper</code> field (pass
345      <code>this</code> into the constructor for <code>DBHelper</code>)
346    </li>
347    <li>
348      Call the <code>open()</code> method on <code>mDbHelper</code> to open (or create) the
349      database.
350    </li>
351    <li>
352      Finally, call a new method <code>fillData()</code>, which will get the data and
353      populate the ListView using the helper &mdash; we haven't defined this method yet.    </li>
354  </ol>
355    <p>
356      <code>onCreate()</code> should now look like this:</p>
357      <pre>
358    &#64;Override
359    public void onCreate(Bundle savedInstanceState) {
360        super.onCreate(savedInstanceState);
361        setContentView(R.layout.notepad_list);
362        mDbHelper = new NotesDbAdapter(this);
363        mDbHelper.open();
364        fillData();
365    }</pre>
366      <p>And be sure you have the <code>mDbHelper</code> field definition (right
367      under the mNoteNumber definition): </p>
368      <pre>    private NotesDbAdapter mDbHelper;</pre>
369
370  <h2>Step 9</h2>
371
372  <div class="sidebox-wrapper">
373  <div class="sidebox">
374    <h2>More about menus</h2>
375    <p>The notepad application we are constructing only scratches the
376     surface with <a href="{@docRoot}resources/faq/commontasks.html#addmenuitems">menus</a>. </p>
377    <p>You can also <a href="{@docRoot}resources/faq/commontasks.html#menukeyshortcuts">add
378shortcut keys for menu items</a>, <a
379href="{@docRoot}resources/faq/commontasks.html#menukeyshortcuts">create
380submenus</a> and even <a href="{@docRoot}resources/faq/commontasks.html#addingtoothermenus">add
381menu items to other applications!</a>. </p>
382  </div>
383  </div>
384
385<p>Fill out the body of the <code>onCreateOptionsMenu()</code> method.</p>
386
387<p>We will now create the "Add Item" button that can be accessed by pressing the menu
388button on the device. We'll specify that it occupy the first position in the menu.</p>
389
390  <ol>
391    <li>
392      In <code>strings.xml</code> resource (under <code>res/values</code>), add
393      a new string named "menu_insert" with its value set to <code>Add Item</code>:
394     <pre>&lt;string name="menu_insert"&gt;Add Item&lt;/string&gt;</pre>
395      <p>Then save the file and return to <code>Notepadv1</code>.</p>
396    </li>
397    <li>Create a menu position constant at the top of the  class:
398      <pre>public static final int INSERT_ID = Menu.FIRST;</pre>
399    </li>
400    <li>In the <code>onCreateOptionsMenu()</code> method, change the
401    <code>super</code> call so we capture the boolean return as <code>result</code>. We'll return this value at the end.</li>
402    <li>Then add the menu item with <code>menu.add()</code>.</li>
403  </ol>
404  <p>The whole method should now look like this:
405      <pre>
406    &#64;Override
407    public boolean onCreateOptionsMenu(Menu menu) {
408        boolean result = super.onCreateOptionsMenu(menu);
409        menu.add(0, INSERT_ID, 0, R.string.menu_insert);
410        return result;
411    }</pre>
412  <p>The arguments passed to <code>add()</code> indicate: a group identifier for this menu (none,
413  in this case), a unique ID (defined above), the order of the item (zero indicates no preference),
414  and the resource of the string to use for the item.</p>
415
416<h2 style="clear:right;">Step 10</h2>
417    <p>Fill out the body of the <code>onOptionsItemSelected()</code> method:</p>
418    <p>This is going
419    to handle our new "Add Note" menu item.  When this is selected, the
420    <code>onOptionsItemSelected()</code> method will be called with the
421    <code>item.getId()</code> set to <code>INSERT_ID</code> (the constant we
422    used to identify the menu item). We can detect this, and take the
423    appropriate actions:</p>
424  <ol>
425    <li>
426      The <code>super.onOptionsItemSelected(item)</code> method call goes at the
427      end of this method &mdash; we want to catch our events first!    </li>
428    <li>
429      Write a switch statement on <code>item.getItemId()</code>.
430      <p>In the case of <var>INSERT_ID</var>, call a new method, <code>createNote()</code>,
431      and return true, because we have handled this event and do not want to
432      propagate it through the system.</p>
433    </li>
434    <li>Return the result of the superclass' <code>onOptionsItemSelected()</code>
435    method at the end.</li>
436   </ol>
437    <p>
438      The whole <code>onOptionsItemSelect()</code> method should now look like
439      this:</p>
440      <pre>
441    &#64;Override
442    public boolean onOptionsItemSelected(MenuItem item) {
443        switch (item.getItemId()) {
444        case INSERT_ID:
445            createNote();
446            return true;
447        }
448
449        return super.onOptionsItemSelected(item);
450    }</pre>
451
452<h2>Step 11</h2>
453    <p>Add a new <code>createNote()</code> method:</p>
454    <p>In this first version of
455    our application, <code>createNote()</code> is not going to be very useful.
456We will simply
457    create a new note with a title assigned to it based on a counter ("Note 1",
458    "Note 2"...) and with an empty body. At present we have no way of editing
459    the contents of a note, so for now we will have to be content making one
460    with some default values:</p>
461  <ol>
462    <li>Construct the name using "Note" and the counter we defined in the class: <code>
463      String noteName = "Note " + mNoteNumber++</code></li>
464    <li>
465      Call <code>mDbHelper.createNote()</code> using <code>noteName</code> as the
466      title and <code>""</code> for the body
467    </li>
468    <li>
469      Call <code>fillData()</code> to populate the list of notes (inefficient but
470      simple) &mdash; we'll create this method next.</li>
471  </ol>
472    <p>
473      The whole <code>createNote()</code> method should look like this: </p>
474      <pre>
475    private void createNote() {
476        String noteName = &quot;Note &quot; + mNoteNumber++;
477        mDbHelper.createNote(noteName, &quot;&quot;);
478        fillData();
479    }</pre>
480
481
482<h2>Step 12</h2>
483  <div class="sidebox-wrapper">
484  <div class="sidebox">
485    <h2>List adapters</h2>
486    <p>Our example uses a {@link android.widget.SimpleCursorAdapter
487     SimpleCursorAdapter} to bind a database {@link android.database.Cursor Cursor}
488     into a ListView, and this is a common way to use a {@link android.widget.ListAdapter
489     ListAdapter}. Other options exist like {@link android.widget.ArrayAdapter ArrayAdapter} which
490     can be used to take a List or Array of in-memory data and bind it in to
491     a list as well.</p>
492  </div>
493  </div>
494
495  <p>Define the <code>fillData()</code> method:</p>
496   <p>This
497    method uses <code>SimpleCursorAdapter,</code> which takes a database <code>Cursor</code>
498    and binds it to fields provided in the layout. These fields define the row elements of our list
499    (in this case we use the <code>text1</code> field in our
500    <code>notes_row.xml</code> layout), so this allows us to easily populate the list with
501    entries from our database.</p>
502    <p>To do this we have to provide a mapping from the <code>title</code> field in the returned Cursor, to
503    our <code>text1</code> TextView, which is done by defining two arrays: the first a string array
504    with the list of columns to map <em>from</em> (just "title" in this case, from the constant
505    <code>NotesDbAdapter.KEY_TITLE</code>) and, the second, an int array
506    containing references to the views that we'll bind the data <em>into</em>
507    (the <code>R.id.text1</code> TextView).</p>
508    <p>This is a bigger chunk of code, so let's first take a look at it:</p>
509
510    <pre>
511    private void fillData() {
512        // Get all of the notes from the database and create the item list
513        Cursor c = mDbHelper.fetchAllNotes();
514        startManagingCursor(c);
515
516        String[] from = new String[] { NotesDbAdapter.KEY_TITLE };
517        int[] to = new int[] { R.id.text1 };
518
519        // Now create an array adapter and set it to display using our row
520        SimpleCursorAdapter notes =
521            new SimpleCursorAdapter(this, R.layout.notes_row, c, from, to);
522        setListAdapter(notes);
523    }</pre>
524
525  <p>Here's what we've done:</p>
526  <ol>
527    <li>
528      After obtaining the Cursor from <code>mDbHelper.fetchAllNotes()</code>, we
529      use an Activity method called
530      <code>startManagingCursor()</code> that allows Android to take care of the
531      Cursor lifecycle instead of us needing to worry about it. (We will cover the implications
532      of the lifecycle in exercise 3, but for now just know that this allows Android to do some
533      of our resource management work for us.)</li>
534    <li>
535      Then we create a string array in which we declare the column(s) we want
536      (just the title, in this case), and an int array that defines the View(s)
537      to which we'd like to bind the columns (these should be in order, respective to
538      the string array, but here we only have one for each).</li>
539    <li>
540      Next is the SimpleCursorAdapter instantiation.
541      Like many classes in Android, the SimpleCursorAdapter needs a Context in order to do its
542      work, so we pass in <code>this</code> for the context (since subclasses of Activity
543      implement Context). We pass the <code>notes_row</code> View we created as the receptacle
544      for the data, the Cursor we just created, and then our arrays.</li>
545   </ol>
546    <p>
547      In the future, remember that the mapping between the <strong>from</strong> columns and <strong>to</strong> resources
548      is done using the respective ordering of the two arrays. If we had more columns we wanted
549      to bind, and more Views to bind them in to, we would specify them in order, for example we
550      might use <code>{ NotesDbAdapter.KEY_TITLE, NotesDbAdapter.KEY_BODY }</code> and
551      <code>{ R.id.text1, R.id.text2 }</code> to bind two fields into the row (and we would also need
552      to define text2 in the notes_row.xml, for the body text). This is how you can bind multiple fields
553      into a single row (and get a custom row layout as well).</p>
554    <p>
555      If you get compiler errors about classes not being found, ctrl-shift-O or
556      (cmd-shift-O on the mac) to organize imports.
557    </p>
558
559<h2 style="clear:right;">Step 13</h2>
560    <p>Run it!
561  <ol>
562    <li>
563      Right click on the <code>Notepadv1</code> project.</li>
564    <li>
565      From the popup menu, select <strong>Run As</strong> &gt;
566      <strong>Android Application</strong>.</li>
567    <li>
568      If you see a dialog come up, select Android Launcher as the way of running
569      the application (you can also use the link near the top of the dialog to
570      set this as your default for the workspace; this is recommended as it will
571      stop the plugin from asking you this every time).</li>
572    <li>Add new notes by hitting the menu button and selecting <em>Add
573    Item</em> from the menu.</li>
574  </ol>
575
576<h2 style="clear:right;">Solution and Next Steps</h2>
577    <p>You can see the solution to this class in <code>Notepadv1Solution</code>
578from
579the zip file to compare with your own.</p>
580
581<p>Once you are ready, move on to <a href="notepad-ex2.html">Tutorial
582Exercise 2</a> to add the ability to create, edit and delete notes.</p>
583
584