Historical errata for Hello, Android

Type typing the word “android” in the Work With field and press. First part doesn’t make sense.

In page 63 the author asks the user to add the attribute \t\tandroid:theme=“@android:style/Theme.Dialog” to manifest.xml, but in fact this attribute was already declared on page 61. I think this attribute should not be in page 61.

Written “res/rawdirectory”, should be “res/raw directory”

“so we put a Music.start( ) call there” should be “so we put a Music.play( ) call there”

You forgot to include, comment and link TranslateTask,java source code:

“Finally, on line 31, we create an instance of TranslateTask…” but no code given.

LinearLayout xml is split between two pages (49 and 50), with a ‘Joe asks’ box between the two fragments. In addition, the positioning of the second fragment (as the layout stands right now) is crowding the text below and could/should be moved up slightly.

Hi,
when introducing the new Activity “.About” in the manifest for the first time, the code example already adds the theme “Theme.Dialog” attribute, although in the text it is described to first have the default theme (fullscreen).

Towards the end of the page the text refers to a method Canvas.setBackgroundResource(), which doesn’t exist. It should be View.setBackgroundResource().

I’m following your examples and creating all files by hand. When adding the menu function including all supporting files and directories, Elipse started showing an Problem/error. I had to find the Error log tab to get the detailed error message “gen [in Suduko] does not exist”. I could not run the project until this error was fixed. The fix for the error was to select Project>Clean from the Eclipse menu and tell it to clean the Suduko project. As a new Eclipse/Java developer it took me a while to find this fix. You may want to make note of this in your final book. In your explination it might be nice to tell readers how to find the error log. A person new to Eclipse, like me, may not know where to find it.

This book is excellent, so far. Exactly what I needed to get started.

Thanks!

Small Suggestion

Move Figure 3.11 after the code for the entry of the Prefs activity into the AndroidManifest. Since I’m walking through the code a step at a time the placement of the image, and caption, made me think I was ready to run the program. I was forced to find the bug myself and fix it. As someone new to Eclipse/Android degugging at this point is a bit daunting. Of course, when I continued reading I noticed the missing piece. I like to think I’m a “typical” user and wouldn’t be the only one to make such a foolish mistake.

The “android:name” of the “provider” tag should be set as “.EventsProvider” instead of “EventsProvider”

The resource directory name should be “res/drawable-nodpi” instead of “res/drawables-nodpi”

Chapter 7.3 “From Javascript to Java and Back”, p. 146

In res/layout/main.xml, the first TextView has its text set with a literal (“TextView”). To maintain consistency with the practices set in the rest of the book, the text should be set from from the strings.xml file the same way the Button widget in the same layout does.

1.4 Running on a Real Phone

You should mentionn that in addition to installing the driver, you need to activate SettingsApplications>Development->USB Debugging. Because the book told me to look for a USB driver by following footnote 7 (which it turns out I already had installed by following the directions in section 1.2), I clicked on “USB Driver for Windows” in the upper right hand corner when I got to the web page. It would have helped me if the book explicitly told me about the configuation that I needed to do on my droid in the main text.

This technique is simple can can
be used to handle most API differences, so we’ll use it here.

Should be “and can” not “can can”

I noticed line numbers on the example code on 103 and 104 pages for the calculateUsedTiles(int x, int y) function

Step 2: “See the sidebar the Joe Asks…” — extra “the”

Fixed vs. Floating Point inset, second paragraph: I think you meant 2^16.

Last sentence of the first paragraph, I think you meant “… by the compiler at build time.”

In the code example you use the attribute start without saying what it is. I had to look into the code to realize that you ment PointF.

You should add the attribute declaration to the Activity snippet above.

In the last paragraph on the page, “course” should be spelled “coarse.”

The book says “I do recommend you add the SDK’s bin directory to your PATH.”
There seems to be no “bin” directory. Do you mean the “tools” directory?

At the ‘Multi-Touch, Introducing Multi-Touch’ in mobi format book, ‘Figure1. Three common touch gestures…’ may be wrong figure. It’s OK in pdf format.

On the title page upper right corner it says “Antroid 1.5 to 2.1”. Since beta 6 the book also covers Froyo (Android 2.2)

Now that Eclipse 3.6 has been released the entire “32-bit vs. 64-bit” section can probably be dropped.

Is it really supposed to say “object to tickle” ?

The footnote (footnote 4) is cut off midsentence.

be passed an object that implements
the OnClickListener Java interface. We’re passing it the

should read

be implemented on an object that implements
the OnClickListener Java interface. We’re passing it the

Typo on first line of the page an “a” where the shouldn’t be one, i.e.
“Once you have a the basic program, change the layout file…”

Is it worth a comment that when you select a link in a webpage in the BrowserView example it opens up a new browser activity?

Not sure if this qualifies as a typo, but the title page notes that this book is for Android 1.5 to 2.1. However, the book does discuss Android 2.2. See PDF page 12, under What’s New in the Third Edition: “The third edition has been updated to support all versions of Android from 1.5 to 2.2 and beyond.” Perhaps the title page graphic is out of date?

The title of the Mobi/Kindle version says “Hello, Android! 2e”. Should it read “Hello, Android! 3e”?

On section 3.4, the first line, it says press CTRL+F11 to switch to landscape. On my computer (win7) I must press the left control + F11. Pressing the right-CTRL + F11 doesn’t switch.

Rotating the Emulator on a Mac is Fn-Ctrl-F12, not just Ctrl-F12 as it is on Windows computers.

Dear Hello Android 3e Support:

I clicked the hyperlinks for the Game.java (.PDF Pg 79) and PuzzelView.java (.PDF Pg 81) files and added them to the org\\example\\sudoku folder. The PuzzleView.java code contained a “R.animn.shake cannot be resolved” error and the Game.java code contained a “Keypad cannot be resolved to a type” error. I did not modify the code, but copied it directly from the server. How do I fix these errors? Am a asking in the proper place? If not, please direct me to the right venue. Thanks and kind regards,

David Bailey

in startGame() on page 66 we use intent.putExtra but it refers to .putExtra as extraData on page 67.

In the isValid function there is “for ( int t : useds)” and in the text it refers to the “used” array, without the “s”.

canvas.drawTextOnPath(QUOTE, circle, 0, 20, tPaint);

tPaint should be cPaint

The context class is used in a lot of code, but I don’t see any explanation of what it is and what it does. Maybe a short description of this would be good?

Third line in method onCreateOptionsMenu(Menu menu) is:

inflater.inflate(R.menu.menu, menu);

It should be:

inflater.inflate(R.layout.menu, menu);

Major Grid Lines part of the code

should it not be i % 3==0 (so two dark lines at 3 and 6 cell?)

when its i % 3 !=0 draws to many black lines.

In many places in the book (PDF version), there are references to pictures like “see something like Figure 3.8, on page 62.”. Many times, the picture itself is unrelated to the text that surrounds it, the best example I could find is Figure 3.8 on page 62, that happened to be inserted within the “3.6 Applying a Theme” section. Also, it requires the user to jump pages. It would be much nicer if the figures were as close to the text as possible.

On page 118, in the Music class, the stop() method takes a Context parameter that is never used. Maybe it would make sense to remove it from there?

The about window is an activity, so when it is shown, the music for the main activity stops playing. Maybe there is a way to create a more robust version of the player that doesn’t stop / start on these activities changes?

The “onRestoreInstanceState” method has an empty return statement that basically does nothing and serves no purpose. Maybe it could be removed?

The code at the bottom of the page, the one that starts the game, passes ‘Sudoku,this’ as the context parameter, whereas it is enough to pass ‘this’. This must be some remainder from when the startGame method was inside the click listener or something. Anyways, it doesn’t serve any purpose now and I think it can only confuse Java newbies. The same code is in the attached sources.

On page 80, in the Game.java class, there is no need to initialize the puzzle array as it will be overwritten anyways by the result of the call to getPuzzle() in onCreate().

The comments on lines 3 and 11 of the calculateUsedTiles method need to be swapped, and the paragraph on pages 100-101 explaining the code has them backwards. In the first ‘for’ loop x is constant, so we’re checking for used numbers in the vertical column as y changes instead of horizontal as the book explains. The second ‘for’ loop is checking horizontally.

Section 1.4, “Running on a Real Phone”, should state that you may need to adjust the SDK platform version of the Hello, Android application to match the one on the phone being used. You may also need to adjust the “Min SDK Version”. This chapter is using Android 2.2. A real phone may have an earlier version installed on it, and it may be useful to quickly cover how to check the phone for its installed version and how to quickly change the Eclipse Project properties to reflect what is on the phone.

The first sentence on page 58 is missing a word. It says “…view it in a couple ways.” instead of “…view it in a couple of ways.”

The download link for Sudoku.java on page 60 of the PDF appears to have been swapped with the one on page 65.

The link on page 60 includes code to support the Options menu but e.g. res/menu/menu.xml has not been created yet; will be by page 65.

Hope this makes sense.

throughout the book it references Sudokuv[0…]/src/org/example/sudoku/…

I take it the [0…] represents separate projects.

The problem is each version is built upon a continuation from the original project. Isn’t this an error?

Thanks.

The sentence in the first bullet point after 14.5 has ‘made’ when it should have ‘make’.

“You can make a paid app free, but you can’t made a free app paid.”

The sentence “We call the PuzzleView.setSelectedTile() method…” in page 98 should be “We call the puzzleView.setSelectedTile() method…”

In the grey highlight box the path to the file is given as:
Sudokuv1/src/org/example/sudoku/Prefs.java
it should be:
Sudokuv1/src/org.example.sudoku/Prefs.java

For developers using Ubuntu Linux, additional set up is required to allow the Eclipse ADK to talk to an attached Android device.

A .rules file is required (or must be edited) so that udev can make the Android device available to the Android Debug Bridge (adb). For instance, /etc/udev/rules.d/99-android.rules

Important to note that the official Android SDK website is out-of-date regarding this. Advise use of the lsusb command to identify the VendorID of the Android device.

Example .rules file record for NexusOne:
SUBSYSTEM"usb", ATTR{idVendor}“18d1”, MODE=“0666”

Some explanation of udev and adb would help readers understand the purpose this set up, such as the numbered prefix of the .rules file (how it affects the load order of rules by udev).

private static final String DATABASE_NAME = “events.db”;
The “events.db” may cause a SQLiteException,
when change it to “events”,it will pass.

Actually, the horizontal line should be x-axis in the screen, so I guess in calculateUsedTiles() method, what the codes do is to traverse from vertical to horizontal.

In two places on this page, I’m guessing you must have changed the keypad from being a separate activity (in a previous version of the book maybe) to being a dialog within the game activity, without completely updating the text to match this new approach.
Anyway, you say: “Now that we have the activity, let’s call it in the Game class…”. I think this should read: “Now that we have the dialog class implementation, let’s call it in the Game class…”.
And at the bottom of the page you say: “we pass the Keypad a string in the extraData area containing…”. But it isn’t a string and it isn’t in the extraData area. I think this should read: “we pass the Keypad an array containing…”.

Best regards, John

Hello, I am actually working with P3.0, November 2010, but there wasn’t an option in the pull down list on this page.

On page 74, the line that includes getTileString(i,j) causes a Force Close when the app is run. The problem is that that Chapter 4 is one big text entry fest (for those of us actually entering code as we go). There is no point where the reader is directed to try to run the code. So, when I got to the D-pad code, I was getting nervous and tried to run the app. Only then did I discover the Force Close error. I had no idea which part of the code caused the error, so I took your advice and used the LogCat window. I discovered that it was the canvas.drawText line and figured out that getTileString was causing the problem. I then saw the note about how getTileString is defined in Section 4.4 on page 81. Turns out getTileString is defined at the very end of 4.4 on page 90. After entering getTileString, I then had to enter other methods it depended on like getTile and then fromPuzzleString, getPuzzle and the 3 puzzle strings.

Up until Chapter 4, the book is paced well for a beginner. Chapter 4 is like the bronco that almost bucked me. It would have been nice to have given the reader the chance to run the code a few times throughout the chapter. That also implies that required code would be entered prior to running. I’ll admit that I felt good after figuring things out, but some readers might be put off by the scavenger hunt I had to go on. FYI.

The layout that is supposed to create a WebView with a button and textbox above it, does not work properly on my Droid X. Instead, all I get is the WebView. I am using the code from this web site. FYI.

pls include a or state to create a new class prefs

When the exit button doesn’t fit in landscape view it also doesn’t fit on low density screens in portrait view.
Although its easily fixed by copying the main.xml from layout-land into a layout-ldpi folder.Just thought you might wanna mention that in the book.

I would like to suggest the use of stub methods during the whole of Chapter 4, where a method call is introduced that calls functionality that has yet to be included. The use of the Eclipse “Quick Fix” feature can generate the skeleton of these methods. Some tweaking may be required to return a meaningful value, but it is fairly minimal. The great advantage would be that the reader can run the app at a number of points during Chapter 4.

Without this, the reader has a long slog to enter all the code before the app is runnable at the very end of the chapter. I realise that the app can be downloaded from the web, but some readers are using this as a learning exercise for Java coding and Eclipse, and will want to enter the code for themselves.

Up to the end of Chapter 3, there are several points at which the app can be run. It would be great if the use of stub methods could be included in the book for Chapter 4.

When drawing background color use
canvas.drawColor(getResources().getColor(R.color.puzzle_background)); as this uses one line of code(Method) instead of two and takes less arguments so its less confusing to a beginner.

In the second paragraph, the sentence, “We’re passing it the this variable, so we had better make the current class (Sudoku) implements that interface, or we’ll get a compiler error.” does not read correctly.

I suspect the word, “sure” is missing after “make”, as in “we had better make sure”.

The other possibility I can see is it was supposed to read “… better make the current class (Sudoku) implement that interface…” - in this case, the error would be that implements is the wrong verb agreement with the noun.

Running on Windows 7 required using Fn+Ctrl+F11 to cause emulator display to switch to alternate layout. Text would suggest that this is only applicable to Mac.

John Webster (hikect@sbcglobal.net)

Instead of “about_title”, needs to be “about_label”.

// AS SEEN IN PDF: android:label=“@string/about_title”>

The changes to AndroidManifest.xml incorrectly highlight (in bold) several lines which are not changed, while the new line of code to be added is not highlighted,
android:theme=“@android:style/Theme.NoTitleBar.Fullscreen” >

In the sentence before heading “Android SDK Components” it is recommended that the PATH be updated to include the “tools” folder of the installed Android SDK. The same recommendation should be made for the “platform-tools” folder, since this is required when running the adb tool, e.g. on page 101 where “adb push” is used in the Video example.

While working through the “Hello, Android” book I’ve taken the opportunity to gain experience with Ubuntu Linux. Coming from a Windows background, even little things like adding a folder to the PATH environment variable can be a challenge (or at least a distraction). In my case I needed to use the command “sudo gedit /etc/environment” and add the path to the colon-delimited list. If this would get in the way within the main line of the book, on page 5, perhaps an Appendix could be added, or a link to the book’s web page.
I know this may be outside the scope of the book, but I am probably not a unique case; adopting Ubuntu as a preferred dev platform seems a natural step in parallel to moving to Android development. Both are open platforms and complement each other. Also, tools such as Git are well suited to Ubuntu devs. Great book, btw :)

My mistake; Not A Problem. (sorry!) I’d missed putting in “about_title” as seen on page 58.

Try{
addEvent(“Hello, Andorid!”); // this should be addEvents
Cursor cursor = getEvents();
ShowEvents(cursor);
}

My title wasn’t properly centering; it was left adjusted. It appears that the TextView for @string/main_title has its layout_gravity set to centered; this (from what I’ve read) would seem to center the control rather than the text. Should you have android:gravity=“center” as well?

In the second to last para of section 7.1, “The next line creates a new Intent class with an action of ACTION_VIEW,
passing it the Uri class just created as the object we want to view.” the word “class” is used twice when referring to instances of those classes.

Page 38 lists the filename of the code block printed is main1.xml, shouldn’t it be main.xml?
Thanks!

Hi Ed, reading your “Helllo, Android”, 3rd edition, was mostly fun but still conveying lots of information — thanks a lot!
I’d just like to mention that the sample code for the Multi-Touch chapter better had not used the raw MotionEvent handling model but the more advanced GestureDetector (since API Level 1; for dragging via OnScroll()) and ScaleGestureDetector (since API level 8; for zooming) classes. I stumbled over these when I was adding (or, actually, had already added) a double-tap handling to restore the untransformed view.
On the other hand I appreciate your recommendations on the support of multiple API levels (pp. 256 ff.) which build upon the handling of exactly the MotionEvent … Anyway, your book was an excellent read and I’m now ready to dig somewhat deeper into the Android’s universe ;)
Kind regards, Manfred

In the code for drawing the major grid lines, there appears to be an error in the line:
if (i % 3 != 0)…
in this case, the heavy line will be drawn for the opposite of the intended case. by switching this to only draw the line when i mod 3 equals 0 (i % 3 == 0) then the issue seems to be resolved.

Thanks,

Brad

android:author=“+string/author" should just be android:author="string/author” without the ‘+’

There’s a semicolon after the closing brace of the onDestroy() method

Theme.Dialog

should be

Theme_Dialog

When I do the “correct” change to Theme_Dialog is get an error in Eclipse but when I used Theme.Dialog it works without a problem. Yes I do know that this is contradictory to the android documentation.

<TextView
………
android:layout_gravity=“center” should that be android:gravity=“center”

Also the web page for the errata “Version” gives an option of 2011-04-11 ….. P6.0
The book gives a different date for P6.0; 2011-3-24

What is the location of the /data folder containing the samplevideo.3gp file?
Thanks!
Receiving message ‘Cannot play video’

The text does not seem to explain why suddenly there are nested elements in the code displayed on pages 40-42. I edited the code gradually, putting the padding, color, and text size (and centering) modifications in the single default LinearLayout, and without adding the enclosing LinearLayout I could still see the results dsiaplyed in Figure 3.4.

I had trouble adapting the activity xml declaration for my own project, where it has “.About” in the sudoku example. I found I needed the whole string eg. “com.example.android.myapp.myActivity”. This was a pernicious error as it wasn’t caught by the spell checker (Eclipse Helios) and took me ages to hunt down!

I am using Eclipse Platform\t3.7.1.r37x_v20110729-9gF7UHOxFtniV7mI3T556iZN9AU8bEZ1lHMcVK. It gave me a compiler error when I typed in the onClick() member function in Sudoku.java. Apparently this version of the compiler is insistent on using the @Override in front of the function definition.

At the bottom of page 67 in the paper book, the “Defining the Game Class” section starts at the very bottom of the page in the space that is normally reserved for footnotes. Not sure if this was by design of if it was intentionally placed there.

The generated code for initial resources produced by Eclipse (Version 3.7.1) creates “res/drawable*/ic_launcher.png”, not “icon.png”. This is also a problem with the first line of the code snippet on pg. 59 (and possibly later in the book). The downloaded version of the code uses “icon.png”. Either change the .png file names to “icon.png” or else change the code listed in the book from “icon.png” to ic_launcher.png". I did the latter and eliminated the problem.

File name conflict for res/drawable*/icon.png. See my comment for this problem listed for page 35.

Chaper 7 The Connected World:

7.1 Browsing by Intent
line 14 “public class BrowserIntent extends Activity” must implement OnClickListner and OnKeyListner.

Audio — You have up to this point made the book standalone.
But I had to go to main.xml in your code to find the layout for the buttons. I think you should have included them by showing main.xml or said that you meant to omit them.
But that they should go in the main.xml and look somewhat like the buttons in Suduko keypad.xml by renaming keypad_1 to button_1. Thank you — an excellent book !!

On the bottom of the page it says “OK, that takes care of writing the program;” however the program was never written. We have just created a new and empty project. The HelloWorld code is nowhere and there was no further mention of the built-in example program mentioned on the top of the page

On page 52 in edition 3 the ID (settings)for the item does not register with the Eclipse ADT plug-in. I am not sure if this is a result of my fault or of the book’s fault, but I have checked over my work many times.

regarding the issue #4953 - that the Settings ID tag does not register in eclipse. I found that by taking out the … the id registers. The … apparently throws eclipse off.

The discussion thread on this book headlined Browser Intent and Browser View problems details my problem in that some code from the tutorial at Section 7.1 needs to be included into the projct at Section 7.2 in order for 7.2 to work. Specifically I beleive that it is the line of code: urlText = (EditText) findViewById(R.id.url_field); needs to be included.
An alternative to that would be to explicitly tell readers that most of the code should e recycled for the project at 7.2.
Hope that helps.

The 1st line in subchapter “6.1 Adding Options to Sudoku”:
“…we used the onCreateOp-tionsMenu()…”. Should be onCreateOptionsMenu() without ‘-’.

Lower part of the page: “the window.an-droid object.” should be without ‘-’.

Example from ch. 7.3 From JavaScript to Java and Back

This example does not work with 2.3 emulators. I tested it with emulator 2.3.3. Problem was reported, see discussion from book forum forums.pragprog.com/forums/152/topics/9720. I also tried it with emulator 3.1 and it works.

This is just a reminder to add some footnote if there is an update of the book.

The button tags in the new layout presented use different string ids than what was previously entered. strings.xml contains continue_label and the like, as does the original layout earlier in the chapter. However, the new layout refers to @string/continue_button, and so on, which is inconsistent.

You need to create res/layout-land/activity_main.xml, not res/layout-land/main.xml

The source code for the Translate Client seems to be missing from gz as well as zip archive.

I followed everything correctly but I keep getting the “translation error”, I also tried to find the source code, but had no luck with that. Could you tell me if this code is out of date or not??

Thanks in advance,
Greeting Christiano Bolla

With upgrade in ADT v22.1 the activity needs to be created separately instead of just new project. Also there is no option for NewAndroid>Andoid Project. You have sample project or new application project.
The default layout now is relative layout.

i have pdf version 2010-7-16
on this page under section 3.8(adding settings) there is a statement “You define
the preferences in a resource file called res/xml/settings.xml”
IAm using adt version 21.1.0. Also iam creating the sudoku app for 4.2.2 JB. Here in the directory structure there is no folder named ‘xml’. Where to create the setting.xml file? Iam Stuck here.. Iam i wrong somewhere??

addPreferencesFromResource method cannot be used as it is deprecated..
what is the alternative for this?plz help

in the section 6.1. The method name onCreateOptionMenu has a dash, I supose it comes from previous versions.

in the override of the OnCreate method for class Prefs you call a method addPreferencesFromResource which has been deprecated (in APIv11). It talks about a new “fragment based preference activity” in the developer reference. It would be lovely if you had an update for this section.

The “callAndroid” method needs a @JavascriptInterface annotation, or else the code won’t compile. More info about that annotation/error can be found on the Android docs. The specific error Eclipse cites is:

None of the methods in the added interface have been annotated with @android.webkit.JavascriptInterface; they will not be visible in API 17